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-rw-r--r--arch/x86/Kbuild3
-rw-r--r--arch/x86/Kconfig2
-rw-r--r--arch/x86/include/asm/lguest.h91
-rw-r--r--arch/x86/include/asm/lguest_hcall.h74
-rw-r--r--arch/x86/include/asm/processor.h2
-rw-r--r--arch/x86/include/uapi/asm/bootparam.h2
-rw-r--r--arch/x86/kernel/asm-offsets_32.c20
-rw-r--r--arch/x86/kernel/head_32.S2
-rw-r--r--arch/x86/kernel/platform-quirks.c1
-rw-r--r--arch/x86/kvm/Kconfig1
-rw-r--r--arch/x86/lguest/Kconfig14
-rw-r--r--arch/x86/lguest/Makefile2
-rw-r--r--arch/x86/lguest/boot.c1558
-rw-r--r--arch/x86/lguest/head_32.S192
14 files changed, 2 insertions, 1962 deletions
diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild
index 586b786b3edf..f65a804b86f0 100644
--- a/arch/x86/Kbuild
+++ b/arch/x86/Kbuild
@@ -10,9 +10,6 @@ obj-$(CONFIG_XEN) += xen/
# Hyper-V paravirtualization support
obj-$(CONFIG_HYPERVISOR_GUEST) += hyperv/
-# lguest paravirtualization support
-obj-$(CONFIG_LGUEST_GUEST) += lguest/
-
obj-y += realmode/
obj-y += kernel/
obj-y += mm/
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 9b302121584d..651021713385 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -777,8 +777,6 @@ config KVM_DEBUG_FS
Statistics are displayed in debugfs filesystem. Enabling this option
may incur significant overhead.
-source "arch/x86/lguest/Kconfig"
-
config PARAVIRT_TIME_ACCOUNTING
bool "Paravirtual steal time accounting"
depends on PARAVIRT
diff --git a/arch/x86/include/asm/lguest.h b/arch/x86/include/asm/lguest.h
deleted file mode 100644
index 73d0c9b92087..000000000000
--- a/arch/x86/include/asm/lguest.h
+++ /dev/null
@@ -1,91 +0,0 @@
-#ifndef _ASM_X86_LGUEST_H
-#define _ASM_X86_LGUEST_H
-
-#define GDT_ENTRY_LGUEST_CS 10
-#define GDT_ENTRY_LGUEST_DS 11
-#define LGUEST_CS (GDT_ENTRY_LGUEST_CS * 8)
-#define LGUEST_DS (GDT_ENTRY_LGUEST_DS * 8)
-
-#ifndef __ASSEMBLY__
-#include <asm/desc.h>
-
-#define GUEST_PL 1
-
-/* Page for Switcher text itself, then two pages per cpu */
-#define SWITCHER_TEXT_PAGES (1)
-#define SWITCHER_STACK_PAGES (2 * nr_cpu_ids)
-#define TOTAL_SWITCHER_PAGES (SWITCHER_TEXT_PAGES + SWITCHER_STACK_PAGES)
-
-/* Where we map the Switcher, in both Host and Guest. */
-extern unsigned long switcher_addr;
-
-/* Found in switcher.S */
-extern unsigned long default_idt_entries[];
-
-/* Declarations for definitions in arch/x86/lguest/head_32.S */
-extern char lguest_noirq_iret[];
-extern const char lgstart_cli[], lgend_cli[];
-extern const char lgstart_pushf[], lgend_pushf[];
-
-extern void lguest_iret(void);
-extern void lguest_init(void);
-
-struct lguest_regs {
- /* Manually saved part. */
- unsigned long eax, ebx, ecx, edx;
- unsigned long esi, edi, ebp;
- unsigned long gs;
- unsigned long fs, ds, es;
- unsigned long trapnum, errcode;
- /* Trap pushed part */
- unsigned long eip;
- unsigned long cs;
- unsigned long eflags;
- unsigned long esp;
- unsigned long ss;
-};
-
-/* This is a guest-specific page (mapped ro) into the guest. */
-struct lguest_ro_state {
- /* Host information we need to restore when we switch back. */
- u32 host_cr3;
- struct desc_ptr host_idt_desc;
- struct desc_ptr host_gdt_desc;
- u32 host_sp;
-
- /* Fields which are used when guest is running. */
- struct desc_ptr guest_idt_desc;
- struct desc_ptr guest_gdt_desc;
- struct x86_hw_tss guest_tss;
- struct desc_struct guest_idt[IDT_ENTRIES];
- struct desc_struct guest_gdt[GDT_ENTRIES];
-};
-
-struct lg_cpu_arch {
- /* The GDT entries copied into lguest_ro_state when running. */
- struct desc_struct gdt[GDT_ENTRIES];
-
- /* The IDT entries: some copied into lguest_ro_state when running. */
- struct desc_struct idt[IDT_ENTRIES];
-
- /* The address of the last guest-visible pagefault (ie. cr2). */
- unsigned long last_pagefault;
-};
-
-static inline void lguest_set_ts(void)
-{
- u32 cr0;
-
- cr0 = read_cr0();
- if (!(cr0 & 8))
- write_cr0(cr0 | 8);
-}
-
-/* Full 4G segment descriptors, suitable for CS and DS. */
-#define FULL_EXEC_SEGMENT \
- ((struct desc_struct)GDT_ENTRY_INIT(0xc09b, 0, 0xfffff))
-#define FULL_SEGMENT ((struct desc_struct)GDT_ENTRY_INIT(0xc093, 0, 0xfffff))
-
-#endif /* __ASSEMBLY__ */
-
-#endif /* _ASM_X86_LGUEST_H */
diff --git a/arch/x86/include/asm/lguest_hcall.h b/arch/x86/include/asm/lguest_hcall.h
deleted file mode 100644
index 6c119cfae218..000000000000
--- a/arch/x86/include/asm/lguest_hcall.h
+++ /dev/null
@@ -1,74 +0,0 @@
-/* Architecture specific portion of the lguest hypercalls */
-#ifndef _ASM_X86_LGUEST_HCALL_H
-#define _ASM_X86_LGUEST_HCALL_H
-
-#define LHCALL_FLUSH_ASYNC 0
-#define LHCALL_LGUEST_INIT 1
-#define LHCALL_SHUTDOWN 2
-#define LHCALL_NEW_PGTABLE 4
-#define LHCALL_FLUSH_TLB 5
-#define LHCALL_LOAD_IDT_ENTRY 6
-#define LHCALL_SET_STACK 7
-#define LHCALL_SET_CLOCKEVENT 9
-#define LHCALL_HALT 10
-#define LHCALL_SET_PMD 13
-#define LHCALL_SET_PTE 14
-#define LHCALL_SET_PGD 15
-#define LHCALL_LOAD_TLS 16
-#define LHCALL_LOAD_GDT_ENTRY 18
-#define LHCALL_SEND_INTERRUPTS 19
-
-#define LGUEST_TRAP_ENTRY 0x1F
-
-/* Argument number 3 to LHCALL_LGUEST_SHUTDOWN */
-#define LGUEST_SHUTDOWN_POWEROFF 1
-#define LGUEST_SHUTDOWN_RESTART 2
-
-#ifndef __ASSEMBLY__
-#include <asm/hw_irq.h>
-
-/*G:030
- * But first, how does our Guest contact the Host to ask for privileged
- * operations? There are two ways: the direct way is to make a "hypercall",
- * to make requests of the Host Itself.
- *
- * Our hypercall mechanism uses the highest unused trap code (traps 32 and
- * above are used by real hardware interrupts). Seventeen hypercalls are
- * available: the hypercall number is put in the %eax register, and the
- * arguments (when required) are placed in %ebx, %ecx, %edx and %esi.
- * If a return value makes sense, it's returned in %eax.
- *
- * Grossly invalid calls result in Sudden Death at the hands of the vengeful
- * Host, rather than returning failure. This reflects Winston Churchill's
- * definition of a gentleman: "someone who is only rude intentionally".
- */
-static inline unsigned long
-hcall(unsigned long call,
- unsigned long arg1, unsigned long arg2, unsigned long arg3,
- unsigned long arg4)
-{
- /* "int" is the Intel instruction to trigger a trap. */
- asm volatile("int $" __stringify(LGUEST_TRAP_ENTRY)
- /* The call in %eax (aka "a") might be overwritten */
- : "=a"(call)
- /* The arguments are in %eax, %ebx, %ecx, %edx & %esi */
- : "a"(call), "b"(arg1), "c"(arg2), "d"(arg3), "S"(arg4)
- /* "memory" means this might write somewhere in memory.
- * This isn't true for all calls, but it's safe to tell
- * gcc that it might happen so it doesn't get clever. */
- : "memory");
- return call;
-}
-/*:*/
-
-/* Can't use our min() macro here: needs to be a constant */
-#define LGUEST_IRQS (NR_IRQS < 32 ? NR_IRQS: 32)
-
-#define LHCALL_RING_SIZE 64
-struct hcall_args {
- /* These map directly onto eax/ebx/ecx/edx/esi in struct lguest_regs */
- unsigned long arg0, arg1, arg2, arg3, arg4;
-};
-
-#endif /* !__ASSEMBLY__ */
-#endif /* _ASM_X86_LGUEST_HCALL_H */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 0b03d655db7c..abc99b9c7ffd 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -662,7 +662,7 @@ static inline void sync_core(void)
* In case NMI unmasking or performance ever becomes a problem,
* the next best option appears to be MOV-to-CR2 and an
* unconditional jump. That sequence also works on all CPUs,
- * but it will fault at CPL3 (i.e. Xen PV and lguest).
+ * but it will fault at CPL3 (i.e. Xen PV).
*
* CPUID is the conventional way, but it's nasty: it doesn't
* exist on some 486-like CPUs, and it usually exits to a
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index ddef37b16af2..66b8f93333d1 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -201,7 +201,7 @@ struct boot_params {
*
* @X86_SUBARCH_PC: Should be used if the hardware is enumerable using standard
* PC mechanisms (PCI, ACPI) and doesn't need a special boot flow.
- * @X86_SUBARCH_LGUEST: Used for x86 hypervisor demo, lguest
+ * @X86_SUBARCH_LGUEST: Used for x86 hypervisor demo, lguest, deprecated
* @X86_SUBARCH_XEN: Used for Xen guest types which follow the PV boot path,
* which start at asm startup_xen() entry point and later jump to the C
* xen_start_kernel() entry point. Both domU and dom0 type of guests are
diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c
index 880aa093268d..710edab9e644 100644
--- a/arch/x86/kernel/asm-offsets_32.c
+++ b/arch/x86/kernel/asm-offsets_32.c
@@ -4,9 +4,6 @@
#include <asm/ucontext.h>
-#include <linux/lguest.h>
-#include "../../../drivers/lguest/lg.h"
-
#define __SYSCALL_I386(nr, sym, qual) [nr] = 1,
static char syscalls[] = {
#include <asm/syscalls_32.h>
@@ -62,23 +59,6 @@ void foo(void)
OFFSET(stack_canary_offset, stack_canary, canary);
#endif
-#if defined(CONFIG_LGUEST) || defined(CONFIG_LGUEST_GUEST) || defined(CONFIG_LGUEST_MODULE)
- BLANK();
- OFFSET(LGUEST_DATA_irq_enabled, lguest_data, irq_enabled);
- OFFSET(LGUEST_DATA_irq_pending, lguest_data, irq_pending);
-
- BLANK();
- OFFSET(LGUEST_PAGES_host_gdt_desc, lguest_pages, state.host_gdt_desc);
- OFFSET(LGUEST_PAGES_host_idt_desc, lguest_pages, state.host_idt_desc);
- OFFSET(LGUEST_PAGES_host_cr3, lguest_pages, state.host_cr3);
- OFFSET(LGUEST_PAGES_host_sp, lguest_pages, state.host_sp);
- OFFSET(LGUEST_PAGES_guest_gdt_desc, lguest_pages,state.guest_gdt_desc);
- OFFSET(LGUEST_PAGES_guest_idt_desc, lguest_pages,state.guest_idt_desc);
- OFFSET(LGUEST_PAGES_guest_gdt, lguest_pages, state.guest_gdt);
- OFFSET(LGUEST_PAGES_regs_trapnum, lguest_pages, regs.trapnum);
- OFFSET(LGUEST_PAGES_regs_errcode, lguest_pages, regs.errcode);
- OFFSET(LGUEST_PAGES_regs, lguest_pages, regs);
-#endif
BLANK();
DEFINE(__NR_syscall_max, sizeof(syscalls) - 1);
DEFINE(NR_syscalls, sizeof(syscalls));
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 0332664eb158..29da9599fec0 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -155,7 +155,6 @@ ENTRY(startup_32)
jmp *%eax
.Lbad_subarch:
-WEAK(lguest_entry)
WEAK(xen_entry)
/* Unknown implementation; there's really
nothing we can do at this point. */
@@ -165,7 +164,6 @@ WEAK(xen_entry)
subarch_entries:
.long .Ldefault_entry /* normal x86/PC */
- .long lguest_entry /* lguest hypervisor */
.long xen_entry /* Xen hypervisor */
.long .Ldefault_entry /* Moorestown MID */
num_subarch_entries = (. - subarch_entries) / 4
diff --git a/arch/x86/kernel/platform-quirks.c b/arch/x86/kernel/platform-quirks.c
index 91271122f0df..502a77d0adb0 100644
--- a/arch/x86/kernel/platform-quirks.c
+++ b/arch/x86/kernel/platform-quirks.c
@@ -16,7 +16,6 @@ void __init x86_early_init_platform_quirks(void)
x86_platform.legacy.reserve_bios_regions = 1;
break;
case X86_SUBARCH_XEN:
- case X86_SUBARCH_LGUEST:
x86_platform.legacy.devices.pnpbios = 0;
x86_platform.legacy.rtc = 0;
break;
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 2688c7dc5323..3ea624452f93 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -89,6 +89,5 @@ config KVM_MMU_AUDIT
# OK, it's a little counter-intuitive to do this, but it puts it neatly under
# the virtualization menu.
source drivers/vhost/Kconfig
-source drivers/lguest/Kconfig
endif # VIRTUALIZATION
diff --git a/arch/x86/lguest/Kconfig b/arch/x86/lguest/Kconfig
deleted file mode 100644
index 08f41caada45..000000000000
--- a/arch/x86/lguest/Kconfig
+++ /dev/null
@@ -1,14 +0,0 @@
-config LGUEST_GUEST
- bool "Lguest guest support"
- depends on X86_32 && PARAVIRT && PCI
- select TTY
- select VIRTUALIZATION
- select VIRTIO
- select VIRTIO_CONSOLE
- help
- Lguest is a tiny in-kernel hypervisor. Selecting this will
- allow your kernel to boot under lguest. This option will increase
- your kernel size by about 10k. If in doubt, say N.
-
- If you say Y here, make sure you say Y (or M) to the virtio block
- and net drivers which lguest needs.
diff --git a/arch/x86/lguest/Makefile b/arch/x86/lguest/Makefile
deleted file mode 100644
index 8f38d577a2fa..000000000000
--- a/arch/x86/lguest/Makefile
+++ /dev/null
@@ -1,2 +0,0 @@
-obj-y := head_32.o boot.o
-CFLAGS_boot.o := $(call cc-option, -fno-stack-protector)
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
deleted file mode 100644
index 99472698c931..000000000000
--- a/arch/x86/lguest/boot.c
+++ /dev/null
@@ -1,1558 +0,0 @@
-/*P:010
- * A hypervisor allows multiple Operating Systems to run on a single machine.
- * To quote David Wheeler: "Any problem in computer science can be solved with
- * another layer of indirection."
- *
- * We keep things simple in two ways. First, we start with a normal Linux
- * kernel and insert a module (lg.ko) which allows us to run other Linux
- * kernels the same way we'd run processes. We call the first kernel the Host,
- * and the others the Guests. The program which sets up and configures Guests
- * (such as the example in tools/lguest/lguest.c) is called the Launcher.
- *
- * Secondly, we only run specially modified Guests, not normal kernels: setting
- * CONFIG_LGUEST_GUEST to "y" compiles this file into the kernel so it knows
- * how to be a Guest at boot time. This means that you can use the same kernel
- * you boot normally (ie. as a Host) as a Guest.
- *
- * These Guests know that they cannot do privileged operations, such as disable
- * interrupts, and that they have to ask the Host to do such things explicitly.
- * This file consists of all the replacements for such low-level native
- * hardware operations: these special Guest versions call the Host.
- *
- * So how does the kernel know it's a Guest? We'll see that later, but let's
- * just say that we end up here where we replace the native functions various
- * "paravirt" structures with our Guest versions, then boot like normal.
-:*/
-
-/*
- * Copyright (C) 2006, Rusty Russell <rusty@rustcorp.com.au> IBM Corporation.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- * NON INFRINGEMENT. See the GNU General Public License for more
- * details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-#include <linux/kernel.h>
-#include <linux/start_kernel.h>
-#include <linux/string.h>
-#include <linux/console.h>
-#include <linux/screen_info.h>
-#include <linux/irq.h>
-#include <linux/interrupt.h>
-#include <linux/clocksource.h>
-#include <linux/clockchips.h>
-#include <linux/lguest.h>
-#include <linux/lguest_launcher.h>
-#include <linux/virtio_console.h>
-#include <linux/pm.h>
-#include <linux/export.h>
-#include <linux/pci.h>
-#include <linux/virtio_pci.h>
-#include <asm/acpi.h>
-#include <asm/apic.h>
-#include <asm/lguest.h>
-#include <asm/paravirt.h>
-#include <asm/param.h>
-#include <asm/page.h>
-#include <asm/pgtable.h>
-#include <asm/desc.h>
-#include <asm/setup.h>
-#include <asm/e820/api.h>
-#include <asm/mce.h>
-#include <asm/io.h>
-#include <asm/fpu/api.h>
-#include <asm/stackprotector.h>
-#include <asm/reboot.h> /* for struct machine_ops */
-#include <asm/kvm_para.h>
-#include <asm/pci_x86.h>
-#include <asm/pci-direct.h>
-
-/*G:010
- * Welcome to the Guest!
- *
- * The Guest in our tale is a simple creature: identical to the Host but
- * behaving in simplified but equivalent ways. In particular, the Guest is the
- * same kernel as the Host (or at least, built from the same source code).
-:*/
-
-struct lguest_data lguest_data = {
- .hcall_status = { [0 ... LHCALL_RING_SIZE-1] = 0xFF },
- .noirq_iret = (u32)lguest_noirq_iret,
- .kernel_address = PAGE_OFFSET,
- .blocked_interrupts = { 1 }, /* Block timer interrupts */
- .syscall_vec = IA32_SYSCALL_VECTOR,
-};
-
-/*G:037
- * async_hcall() is pretty simple: I'm quite proud of it really. We have a
- * ring buffer of stored hypercalls which the Host will run though next time we
- * do a normal hypercall. Each entry in the ring has 5 slots for the hypercall
- * arguments, and a "hcall_status" word which is 0 if the call is ready to go,
- * and 255 once the Host has finished with it.
- *
- * If we come around to a slot which hasn't been finished, then the table is
- * full and we just make the hypercall directly. This has the nice side
- * effect of causing the Host to run all the stored calls in the ring buffer
- * which empties it for next time!
- */
-static void async_hcall(unsigned long call, unsigned long arg1,
- unsigned long arg2, unsigned long arg3,
- unsigned long arg4)
-{
- /* Note: This code assumes we're uniprocessor. */
- static unsigned int next_call;
- unsigned long flags;
-
- /*
- * Disable interrupts if not already disabled: we don't want an
- * interrupt handler making a hypercall while we're already doing
- * one!
- */
- local_irq_save(flags);
- if (lguest_data.hcall_status[next_call] != 0xFF) {
- /* Table full, so do normal hcall which will flush table. */
- hcall(call, arg1, arg2, arg3, arg4);
- } else {
- lguest_data.hcalls[next_call].arg0 = call;
- lguest_data.hcalls[next_call].arg1 = arg1;
- lguest_data.hcalls[next_call].arg2 = arg2;
- lguest_data.hcalls[next_call].arg3 = arg3;
- lguest_data.hcalls[next_call].arg4 = arg4;
- /* Arguments must all be written before we mark it to go */
- wmb();
- lguest_data.hcall_status[next_call] = 0;
- if (++next_call == LHCALL_RING_SIZE)
- next_call = 0;
- }
- local_irq_restore(flags);
-}
-
-/*G:035
- * Notice the lazy_hcall() above, rather than hcall(). This is our first real
- * optimization trick!
- *
- * When lazy_mode is set, it means we're allowed to defer all hypercalls and do
- * them as a batch when lazy_mode is eventually turned off. Because hypercalls
- * are reasonably expensive, batching them up makes sense. For example, a
- * large munmap might update dozens of page table entries: that code calls
- * paravirt_enter_lazy_mmu(), does the dozen updates, then calls
- * lguest_leave_lazy_mode().
- *
- * So, when we're in lazy mode, we call async_hcall() to store the call for
- * future processing:
- */
-static void lazy_hcall1(unsigned long call, unsigned long arg1)
-{
- if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE)
- hcall(call, arg1, 0, 0, 0);
- else
- async_hcall(call, arg1, 0, 0, 0);
-}
-
-/* You can imagine what lazy_hcall2, 3 and 4 look like. :*/
-static void lazy_hcall2(unsigned long call,
- unsigned long arg1,
- unsigned long arg2)
-{
- if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE)
- hcall(call, arg1, arg2, 0, 0);
- else
- async_hcall(call, arg1, arg2, 0, 0);
-}
-
-static void lazy_hcall3(unsigned long call,
- unsigned long arg1,
- unsigned long arg2,
- unsigned long arg3)
-{
- if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE)
- hcall(call, arg1, arg2, arg3, 0);
- else
- async_hcall(call, arg1, arg2, arg3, 0);
-}
-
-#ifdef CONFIG_X86_PAE
-static void lazy_hcall4(unsigned long call,
- unsigned long arg1,
- unsigned long arg2,
- unsigned long arg3,
- unsigned long arg4)
-{
- if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE)
- hcall(call, arg1, arg2, arg3, arg4);
- else
- async_hcall(call, arg1, arg2, arg3, arg4);
-}
-#endif
-
-/*G:036
- * When lazy mode is turned off, we issue the do-nothing hypercall to
- * flush any stored calls, and call the generic helper to reset the
- * per-cpu lazy mode variable.
- */
-static void lguest_leave_lazy_mmu_mode(void)
-{
- hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0, 0);
- paravirt_leave_lazy_mmu();
-}
-
-/*
- * We also catch the end of context switch; we enter lazy mode for much of
- * that too, so again we need to flush here.
- *
- * (Technically, this is lazy CPU mode, and normally we're in lazy MMU
- * mode, but unlike Xen, lguest doesn't care about the difference).
- */
-static void lguest_end_context_switch(struct task_struct *next)
-{
- hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0, 0);
- paravirt_end_context_switch(next);
-}
-
-/*G:032
- * After that diversion we return to our first native-instruction
- * replacements: four functions for interrupt control.
- *
- * The simplest way of implementing these would be to have "turn interrupts
- * off" and "turn interrupts on" hypercalls. Unfortunately, this is too slow:
- * these are by far the most commonly called functions of those we override.
- *
- * So instead we keep an "irq_enabled" field inside our "struct lguest_data",
- * which the Guest can update with a single instruction. The Host knows to
- * check there before it tries to deliver an interrupt.
- */
-
-/*
- * save_flags() is expected to return the processor state (ie. "flags"). The
- * flags word contains all kind of stuff, but in practice Linux only cares
- * about the interrupt flag. Our "save_flags()" just returns that.
- */
-asmlinkage __visible unsigned long lguest_save_fl(void)
-{
- return lguest_data.irq_enabled;
-}
-
-/* Interrupts go off... */
-asmlinkage __visible void lguest_irq_disable(void)
-{
- lguest_data.irq_enabled = 0;
-}
-
-/*
- * Let's pause a moment. Remember how I said these are called so often?
- * Jeremy Fitzhardinge optimized them so hard early in 2009 that he had to
- * break some rules. In particular, these functions are assumed to save their
- * own registers if they need to: normal C functions assume they can trash the
- * eax register. To use normal C functions, we use
- * PV_CALLEE_SAVE_REGS_THUNK(), which pushes %eax onto the stack, calls the
- * C function, then restores it.
- */
-PV_CALLEE_SAVE_REGS_THUNK(lguest_save_fl);
-PV_CALLEE_SAVE_REGS_THUNK(lguest_irq_disable);
-/*:*/
-
-/* These are in head_32.S */
-extern void lg_irq_enable(void);
-extern void lg_restore_fl(unsigned long flags);
-
-/*M:003
- * We could be more efficient in our checking of outstanding interrupts, rather
- * than using a branch. One way would be to put the "irq_enabled" field in a
- * page by itself, and have the Host write-protect it when an interrupt comes
- * in when irqs are disabled. There will then be a page fault as soon as
- * interrupts are re-enabled.
- *
- * A better method is to implement soft interrupt disable generally for x86:
- * instead of disabling interrupts, we set a flag. If an interrupt does come
- * in, we then disable them for real. This is uncommon, so we could simply use
- * a hypercall for interrupt control and not worry about efficiency.
-:*/
-
-/*G:034
- * The Interrupt Descriptor Table (IDT).
- *
- * The IDT tells the processor what to do when an interrupt comes in. Each
- * entry in the table is a 64-bit descriptor: this holds the privilege level,
- * address of the handler, and... well, who cares? The Guest just asks the
- * Host to make the change anyway, because the Host controls the real IDT.
- */
-static void lguest_write_idt_entry(gate_desc *dt,
- int entrynum, const gate_desc *g)
-{
- /*
- * The gate_desc structure is 8 bytes long: we hand it to the Host in
- * two 32-bit chunks. The whole 32-bit kernel used to hand descriptors
- * around like this; typesafety wasn't a big concern in Linux's early
- * years.
- */
- u32 *desc = (u32 *)g;
- /* Keep the local copy up to date. */
- native_write_idt_entry(dt, entrynum, g);
- /* Tell Host about this new entry. */
- hcall(LHCALL_LOAD_IDT_ENTRY, entrynum, desc[0], desc[1], 0);
-}
-
-/*
- * Changing to a different IDT is very rare: we keep the IDT up-to-date every
- * time it is written, so we can simply loop through all entries and tell the
- * Host about them.
- */
-static void lguest_load_idt(const struct desc_ptr *desc)
-{
- unsigned int i;
- struct desc_struct *idt = (void *)desc->address;
-
- for (i = 0; i < (desc->size+1)/8; i++)
- hcall(LHCALL_LOAD_IDT_ENTRY, i, idt[i].a, idt[i].b, 0);
-}
-
-/*
- * The Global Descriptor Table.
- *
- * The Intel architecture defines another table, called the Global Descriptor
- * Table (GDT). You tell the CPU where it is (and its size) using the "lgdt"
- * instruction, and then several other instructions refer to entries in the
- * table. There are three entries which the Switcher needs, so the Host simply
- * controls the entire thing and the Guest asks it to make changes using the
- * LOAD_GDT hypercall.
- *
- * This is the exactly like the IDT code.
- */
-static void lguest_load_gdt(const struct desc_ptr *desc)
-{
- unsigned int i;
- struct desc_struct *gdt = (void *)desc->address;
-
- for (i = 0; i < (desc->size+1)/8; i++)
- hcall(LHCALL_LOAD_GDT_ENTRY, i, gdt[i].a, gdt[i].b, 0);
-}
-
-/*
- * For a single GDT entry which changes, we simply change our copy and
- * then tell the host about it.
- */
-static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum,
- const void *desc, int type)
-{
- native_write_gdt_entry(dt, entrynum, desc, type);
- /* Tell Host about this new entry. */
- hcall(LHCALL_LOAD_GDT_ENTRY, entrynum,
- dt[entrynum].a, dt[entrynum].b, 0);
-}
-
-/*
- * There are three "thread local storage" GDT entries which change
- * on every context switch (these three entries are how glibc implements
- * __thread variables). As an optimization, we have a hypercall
- * specifically for this case.
- *
- * Wouldn't it be nicer to have a general LOAD_GDT_ENTRIES hypercall
- * which took a range of entries?
- */
-static void lguest_load_tls(struct thread_struct *t, unsigned int cpu)
-{
- /*
- * There's one problem which normal hardware doesn't have: the Host
- * can't handle us removing entries we're currently using. So we clear
- * the GS register here: if it's needed it'll be reloaded anyway.
- */
- lazy_load_gs(0);
- lazy_hcall2(LHCALL_LOAD_TLS, __pa(&t->tls_array), cpu);
-}
-
-/*G:038
- * That's enough excitement for now, back to ploughing through each of the
- * different pv_ops structures (we're about 1/3 of the way through).
- *
- * This is the Local Descriptor Table, another weird Intel thingy. Linux only
- * uses this for some strange applications like Wine. We don't do anything
- * here, so they'll get an informative and friendly Segmentation Fault.
- */
-static void lguest_set_ldt(const void *addr, unsigned entries)
-{
-}
-
-/*
- * This loads a GDT entry into the "Task Register": that entry points to a
- * structure called the Task State Segment. Some comments scattered though the
- * kernel code indicate that this used for task switching in ages past, along
- * with blood sacrifice and astrology.
- *
- * Now there's nothing interesting in here that we don't get told elsewhere.
- * But the native version uses the "ltr" instruction, which makes the Host
- * complain to the Guest about a Segmentation Fault and it'll oops. So we
- * override the native version with a do-nothing version.
- */
-static void lguest_load_tr_desc(void)
-{
-}
-
-/*
- * The "cpuid" instruction is a way of querying both the CPU identity
- * (manufacturer, model, etc) and its features. It was introduced before the
- * Pentium in 1993 and keeps getting extended by both Intel, AMD and others.
- * As you might imagine, after a decade and a half this treatment, it is now a
- * giant ball of hair. Its entry in the current Intel manual runs to 28 pages.
- *
- * This instruction even it has its own Wikipedia entry. The Wikipedia entry
- * has been translated into 6 languages. I am not making this up!
- *
- * We could get funky here and identify ourselves as "GenuineLguest", but
- * instead we just use the real "cpuid" instruction. Then I pretty much turned
- * off feature bits until the Guest booted. (Don't say that: you'll damage
- * lguest sales!) Shut up, inner voice! (Hey, just pointing out that this is
- * hardly future proof.) No one's listening! They don't like you anyway,
- * parenthetic weirdo!
- *
- * Replacing the cpuid so we can turn features off is great for the kernel, but
- * anyone (including userspace) can just use the raw "cpuid" instruction and
- * the Host won't even notice since it isn't privileged. So we try not to get
- * too worked up about it.
- */
-static void lguest_cpuid(unsigned int *ax, unsigned int *bx,
- unsigned int *cx, unsigned int *dx)
-{
- int function = *ax;
-
- native_cpuid(ax, bx, cx, dx);
- switch (function) {
- /*
- * CPUID 0 gives the highest legal CPUID number (and the ID string).
- * We futureproof our code a little by sticking to known CPUID values.
- */
- case 0:
- if (*ax > 5)
- *ax = 5;
- break;
-
- /*
- * CPUID 1 is a basic feature request.
- *
- * CX: we only allow kernel to see SSE3, CMPXCHG16B and SSSE3
- * DX: SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, TSC, FPU and PAE.
- */
- case 1:
- *cx &= 0x00002201;
- *dx &= 0x07808151;
- /*
- * The Host can do a nice optimization if it knows that the
- * kernel mappings (addresses above 0xC0000000 or whatever
- * PAGE_OFFSET is set to) haven't changed. But Linux calls
- * flush_tlb_user() for both user and kernel mappings unless
- * the Page Global Enable (PGE) feature bit is set.
- */
- *dx |= 0x00002000;
- /*
- * We also lie, and say we're family id 5. 6 or greater
- * leads to a rdmsr in early_init_intel which we can't handle.
- * Family ID is returned as bits 8-12 in ax.
- */
- *ax &= 0xFFFFF0FF;
- *ax |= 0x00000500;
- break;
-
- /*
- * This is used to detect if we're running under KVM. We might be,
- * but that's a Host matter, not us. So say we're not.
- */
- case KVM_CPUID_SIGNATURE:
- *bx = *cx = *dx = 0;
- break;
-
- /*
- * 0x80000000 returns the highest Extended Function, so we futureproof
- * like we do above by limiting it to known fields.
- */
- case 0x80000000:
- if (*ax > 0x80000008)
- *ax = 0x80000008;
- break;
-
- /*
- * PAE systems can mark pages as non-executable. Linux calls this the
- * NX bit. Intel calls it XD (eXecute Disable), AMD EVP (Enhanced
- * Virus Protection). We just switch it off here, since we don't
- * support it.
- */
- case 0x80000001:
- *dx &= ~(1 << 20);
- break;
- }
-}
-
-/*
- * Intel has four control registers, imaginatively named cr0, cr2, cr3 and cr4.
- * I assume there's a cr1, but it hasn't bothered us yet, so we'll not bother
- * it. The Host needs to know when the Guest wants to change them, so we have
- * a whole series of functions like read_cr0() and write_cr0().
- *
- * We start with cr0. cr0 allows you to turn on and off all kinds of basic
- * features, but the only cr0 bit that Linux ever used at runtime was the
- * horrifically-named Task Switched (TS) bit at bit 3 (ie. 8)
- *
- * What does the TS bit do? Well, it causes the CPU to trap (interrupt 7) if
- * the floating point unit is used. Which allows us to restore FPU state
- * lazily after a task switch if we wanted to, but wouldn't a name like
- * "FPUTRAP bit" be a little less cryptic?
- *
- * Fortunately, Linux keeps it simple and doesn't use TS, so we can ignore
- * cr0.
- */
-static void lguest_write_cr0(unsigned long val)
-{
-}
-
-static unsigned long lguest_read_cr0(void)
-{
- return 0;
-}
-
-/*
- * cr2 is the virtual address of the last page fault, which the Guest only ever
- * reads. The Host kindly writes this into our "struct lguest_data", so we
- * just read it out of there.
- */
-static unsigned long lguest_read_cr2(void)
-{
- return lguest_data.cr2;
-}
-
-/* See lguest_set_pte() below. */
-static bool cr3_changed = false;
-static unsigned long current_cr3;
-
-/*
- * cr3 is the current toplevel pagetable page: the principle is the same as
- * cr0. Keep a local copy, and tell the Host when it changes.
- */
-static void lguest_write_cr3(unsigned long cr3)
-{
- lazy_hcall1(LHCALL_NEW_PGTABLE, cr3);
- current_cr3 = cr3;
-
- /* These two page tables are simple, linear, and used during boot */
- if (cr3 != __pa_symbol(swapper_pg_dir) &&
- cr3 != __pa_symbol(initial_page_table))
- cr3_changed = true;
-}
-
-static unsigned long lguest_read_cr3(void)
-{
- return current_cr3;
-}
-
-/* cr4 is used to enable and disable PGE, but we don't care. */
-static unsigned long lguest_read_cr4(void)
-{
- return 0;
-}
-
-static void lguest_write_cr4(unsigned long val)
-{
-}
-
-/*
- * Page Table Handling.
- *
- * Now would be a good time to take a rest and grab a coffee or similarly
- * relaxing stimulant. The easy parts are behind us, and the trek gradually
- * winds uphill from here.
- *
- * Quick refresher: memory is divided into "pages" of 4096 bytes each. The CPU
- * maps virtual addresses to physical addresses using "page tables". We could
- * use one huge index of 1 million entries: each address is 4 bytes, so that's
- * 1024 pages just to hold the page tables. But since most virtual addresses
- * are unused, we use a two level index which saves space. The cr3 register
- * contains the physical address of the top level "page directory" page, which
- * contains physical addresses of up to 1024 second-level pages. Each of these
- * second level pages contains up to 1024 physical addresses of actual pages,
- * or Page Table Entries (PTEs).
- *
- * Here's a diagram, where arrows indicate physical addresses:
- *
- * cr3 ---> +---------+
- * | --------->+---------+
- * | | | PADDR1 |
- * Mid-level | | PADDR2 |
- * (PMD) page | | |
- * | | Lower-level |
- * | | (PTE) page |
- * | | | |
- * .... ....
- *
- * So to convert a virtual address to a physical address, we look up the top
- * level, which points us to the second level, which gives us the physical
- * address of that page. If the top level entry was not present, or the second
- * level entry was not present, then the virtual address is invalid (we
- * say "the page was not mapped").
- *
- * Put another way, a 32-bit virtual address is divided up like so:
- *
- * 1 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
- * |<---- 10 bits ---->|<---- 10 bits ---->|<------ 12 bits ------>|
- * Index into top Index into second Offset within page
- * page directory page pagetable page
- *
- * Now, unfortunately, this isn't the whole story: Intel added Physical Address
- * Extension (PAE) to allow 32 bit systems to use 64GB of memory (ie. 36 bits).
- * These are held in 64-bit page table entries, so we can now only fit 512
- * entries in a page, and the neat three-level tree breaks down.
- *
- * The result is a four level page table:
- *
- * cr3 --> [ 4 Upper ]
- * [ Level ]
- * [ Entries ]
- * [(PUD Page)]---> +---------+
- * | --------->+---------+
- * | | | PADDR1 |
- * Mid-level | | PADDR2 |
- * (PMD) page | | |
- * | | Lower-level |
- * | | (PTE) page |
- * | | | |
- * .... ....
- *
- *
- * And the virtual address is decoded as:
- *
- * 1 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
- * |<-2->|<--- 9 bits ---->|<---- 9 bits --->|<------ 12 bits ------>|
- * Index into Index into mid Index into lower Offset within page
- * top entries directory page pagetable page
- *
- * It's too hard to switch between these two formats at runtime, so Linux only
- * supports one or the other depending on whether CONFIG_X86_PAE is set. Many
- * distributions turn it on, and not just for people with silly amounts of
- * memory: the larger PTE entries allow room for the NX bit, which lets the
- * kernel disable execution of pages and increase security.
- *
- * This was a problem for lguest, which couldn't run on these distributions;
- * then Matias Zabaljauregui figured it all out and implemented it, and only a
- * handful of puppies were crushed in the process!
- *
- * Back to our point: the kernel spends a lot of time changing both the
- * top-level page directory and lower-level pagetable pages. The Guest doesn't
- * know physical addresses, so while it maintains these page tables exactly
- * like normal, it also needs to keep the Host informed whenever it makes a
- * change: the Host will create the real page tables based on the Guests'.
- */
-
-/*
- * The Guest calls this after it has set a second-level entry (pte), ie. to map
- * a page into a process' address space. We tell the Host the toplevel and
- * address this corresponds to. The Guest uses one pagetable per process, so
- * we need to tell the Host which one we're changing (mm->pgd).
- */
-static void lguest_pte_update(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep)
-{
-#ifdef CONFIG_X86_PAE
- /* PAE needs to hand a 64 bit page table entry, so it uses two args. */
- lazy_hcall4(LHCALL_SET_PTE, __pa(mm->pgd), addr,
- ptep->pte_low, ptep->pte_high);
-#else
- lazy_hcall3(LHCALL_SET_PTE, __pa(mm->pgd), addr, ptep->pte_low);
-#endif
-}
-
-/* This is the "set and update" combo-meal-deal version. */
-static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep, pte_t pteval)
-{
- native_set_pte(ptep, pteval);
- lguest_pte_update(mm, addr, ptep);
-}
-
-/*
- * The Guest calls lguest_set_pud to set a top-level entry and lguest_set_pmd
- * to set a middle-level entry when PAE is activated.
- *
- * Again, we set the entry then tell the Host which page we changed,
- * and the index of the entry we changed.
- */
-#ifdef CONFIG_X86_PAE
-static void lguest_set_pud(pud_t *pudp, pud_t pudval)
-{
- native_set_pud(pudp, pudval);
-
- /* 32 bytes aligned pdpt address and the index. */
- lazy_hcall2(LHCALL_SET_PGD, __pa(pudp) & 0xFFFFFFE0,
- (__pa(pudp) & 0x1F) / sizeof(pud_t));
-}
-
-static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
-{
- native_set_pmd(pmdp, pmdval);
- lazy_hcall2(LHCALL_SET_PMD, __pa(pmdp) & PAGE_MASK,
- (__pa(pmdp) & (PAGE_SIZE - 1)) / sizeof(pmd_t));
-}
-#else
-
-/* The Guest calls lguest_set_pmd to set a top-level entry when !PAE. */
-static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
-{
- native_set_pmd(pmdp, pmdval);
- lazy_hcall2(LHCALL_SET_PGD, __pa(pmdp) & PAGE_MASK,
- (__pa(pmdp) & (PAGE_SIZE - 1)) / sizeof(pmd_t));
-}
-#endif
-
-/*
- * There are a couple of legacy places where the kernel sets a PTE, but we
- * don't know the top level any more. This is useless for us, since we don't
- * know which pagetable is changing or what address, so we just tell the Host
- * to forget all of them. Fortunately, this is very rare.
- *
- * ... except in early boot when the kernel sets up the initial pagetables,
- * which makes booting astonishingly slow: 48 seconds! So we don't even tell
- * the Host anything changed until we've done the first real page table switch,
- * which brings boot back to 4.3 seconds.
- */
-static void lguest_set_pte(pte_t *ptep, pte_t pteval)
-{
- native_set_pte(ptep, pteval);
- if (cr3_changed)
- lazy_hcall1(LHCALL_FLUSH_TLB, 1);
-}
-
-#ifdef CONFIG_X86_PAE
-/*
- * With 64-bit PTE values, we need to be careful setting them: if we set 32
- * bits at a time, the hardware could see a weird half-set entry. These
- * versions ensure we update all 64 bits at once.
- */
-static void lguest_set_pte_atomic(pte_t *ptep, pte_t pte)
-{
- native_set_pte_atomic(ptep, pte);
- if (cr3_changed)
- lazy_hcall1(LHCALL_FLUSH_TLB, 1);
-}
-
-static void lguest_pte_clear(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep)
-{
- native_pte_clear(mm, addr, ptep);
- lguest_pte_update(mm, addr, ptep);
-}
-
-static void lguest_pmd_clear(pmd_t *pmdp)
-{
- lguest_set_pmd(pmdp, __pmd(0));
-}
-#endif
-
-/*
- * Unfortunately for Lguest, the pv_mmu_ops for page tables were based on
- * native page table operations. On native hardware you can set a new page
- * table entry whenever you want, but if you want to remove one you have to do
- * a TLB flush (a TLB is a little cache of page table entries kept by the CPU).
- *
- * So the lguest_set_pte_at() and lguest_set_pmd() functions above are only
- * called when a valid entry is written, not when it's removed (ie. marked not
- * present). Instead, this is where we come when the Guest wants to remove a
- * page table entry: we tell the Host to set that entry to 0 (ie. the present
- * bit is zero).
- */
-static void lguest_flush_tlb_single(unsigned long addr)
-{
- /* Simply set it to zero: if it was not, it will fault back in. */
- lazy_hcall3(LHCALL_SET_PTE, current_cr3, addr, 0);
-}
-
-/*
- * This is what happens after the Guest has removed a large number of entries.
- * This tells the Host that any of the page table entries for userspace might
- * have changed, ie. virtual addresses below PAGE_OFFSET.
- */
-static void lguest_flush_tlb_user(void)
-{
- lazy_hcall1(LHCALL_FLUSH_TLB, 0);
-}
-
-/*
- * This is called when the kernel page tables have changed. That's not very
- * common (unless the Guest is using highmem, which makes the Guest extremely
- * slow), so it's worth separating this from the user flushing above.
- */
-static void lguest_flush_tlb_kernel(void)
-{
- lazy_hcall1(LHCALL_FLUSH_TLB, 1);
-}
-
-/*
- * The Unadvanced Programmable Interrupt Controller.
- *
- * This is an attempt to implement the simplest possible interrupt controller.
- * I spent some time looking though routines like set_irq_chip_and_handler,
- * set_irq_chip_and_handler_name, set_irq_chip_data and set_phasers_to_stun and
- * I *think* this is as simple as it gets.
- *
- * We can tell the Host what interrupts we want blocked ready for using the
- * lguest_data.interrupts bitmap, so disabling (aka "masking") them is as
- * simple as setting a bit. We don't actually "ack" interrupts as such, we
- * just mask and unmask them. I wonder if we should be cleverer?
- */
-static void disable_lguest_irq(struct irq_data *data)
-{
- set_bit(data->irq, lguest_data.blocked_interrupts);
-}
-
-static void enable_lguest_irq(struct irq_data *data)
-{
- clear_bit(data->irq, lguest_data.blocked_interrupts);
-}
-
-/* This structure describes the lguest IRQ controller. */
-static struct irq_chip lguest_irq_controller = {
- .name = "lguest",
- .irq_mask = disable_lguest_irq,
- .irq_mask_ack = disable_lguest_irq,
- .irq_unmask = enable_lguest_irq,
-};
-
-/*
- * Interrupt descriptors are allocated as-needed, but low-numbered ones are
- * reserved by the generic x86 code. So we ignore irq_alloc_desc_at if it
- * tells us the irq is already used: other errors (ie. ENOMEM) we take
- * seriously.
- */
-static int lguest_setup_irq(unsigned int irq)
-{
- struct irq_desc *desc;
- int err;
-
- /* Returns -ve error or vector number. */
- err = irq_alloc_desc_at(irq, 0);
- if (err < 0 && err != -EEXIST)
- return err;
-
- /*
- * Tell the Linux infrastructure that the interrupt is
- * controlled by our level-based lguest interrupt controller.
- */
- irq_set_chip_and_handler_name(irq, &lguest_irq_controller,
- handle_level_irq, "level");
-
- /* Some systems map "vectors" to interrupts weirdly. Not us! */
- desc = irq_to_desc(irq);
- __this_cpu_write(vector_irq[FIRST_EXTERNAL_VECTOR + irq], desc);
- return 0;
-}
-
-static int lguest_enable_irq(struct pci_dev *dev)
-{
- int err;
- u8 line = 0;
-
- /* We literally use the PCI interrupt line as the irq number. */
- pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &line);
- err = lguest_setup_irq(line);
- if (!err)
- dev->irq = line;
- return err;
-}
-
-/* We don't do hotplug PCI, so this shouldn't be called. */
-static void lguest_disable_irq(struct pci_dev *dev)
-{
- WARN_ON(1);
-}
-
-/*
- * This sets up the Interrupt Descriptor Table (IDT) entry for each hardware
- * interrupt (except 128, which is used for system calls).
- */
-static void __init lguest_init_IRQ(void)
-{
- unsigned int i;
-
- for (i = FIRST_EXTERNAL_VECTOR; i < FIRST_SYSTEM_VECTOR; i++) {
- if (i != IA32_SYSCALL_VECTOR)
- set_intr_gate(i, irq_entries_start +
- 8 * (i - FIRST_EXTERNAL_VECTOR));
- }
-
- /*
- * This call is required to set up for 4k stacks, where we have
- * separate stacks for hard and soft interrupts.
- */
- irq_ctx_init(smp_processor_id());
-}
-
-/*
- * Time.
- *
- * It would be far better for everyone if the Guest had its own clock, but
- * until then the Host gives us the time on every interrupt.
- */
-static void lguest_get_wallclock(struct timespec *now)
-{
- *now = lguest_data.time;
-}
-
-/*
- * The TSC is an Intel thing called the Time Stamp Counter. The Host tells us
- * what speed it runs at, or 0 if it's unusable as a reliable clock source.
- * This matches what we want here: if we return 0 from this function, the x86
- * TSC clock will give up and not register itself.
- */
-static unsigned long lguest_tsc_khz(void)
-{
- return lguest_data.tsc_khz;
-}
-
-/*
- * If we can't use the TSC, the kernel falls back to our lower-priority
- * "lguest_clock", where we read the time value given to us by the Host.
- */
-static u64 lguest_clock_read(struct clocksource *cs)
-{
- unsigned long sec, nsec;
-
- /*
- * Since the time is in two parts (seconds and nanoseconds), we risk
- * reading it just as it's changing from 99 & 0.999999999 to 100 and 0,
- * and getting 99 and 0. As Linux tends to come apart under the stress
- * of time travel, we must be careful:
- */
- do {
- /* First we read the seconds part. */
- sec = lguest_data.time.tv_sec;
- /*
- * This read memory barrier tells the compiler and the CPU that
- * this can't be reordered: we have to complete the above
- * before going on.
- */
- rmb();
- /* Now we read the nanoseconds part. */
- nsec = lguest_data.time.tv_nsec;
- /* Make sure we've done that. */
- rmb();
- /* Now if the seconds part has changed, try again. */
- } while (unlikely(lguest_data.time.tv_sec != sec));
-
- /* Our lguest clock is in real nanoseconds. */
- return sec*1000000000ULL + nsec;
-}
-
-/* This is the fallback clocksource: lower priority than the TSC clocksource. */
-static struct clocksource lguest_clock = {
- .name = "lguest",
- .rating = 200,
- .read = lguest_clock_read,
- .mask = CLOCKSOURCE_MASK(64),
- .flags = CLOCK_SOURCE_IS_CONTINUOUS,
-};
-
-/*
- * We also need a "struct clock_event_device": Linux asks us to set it to go
- * off some time in the future. Actually, James Morris figured all this out, I
- * just applied the patch.
- */
-static int lguest_clockevent_set_next_event(unsigned long delta,
- struct clock_event_device *evt)
-{
- /* FIXME: I don't think this can ever happen, but James tells me he had
- * to put this code in. Maybe we should remove it now. Anyone? */
- if (delta < LG_CLOCK_MIN_DELTA) {
- if (printk_ratelimit())
- printk(KERN_DEBUG "%s: small delta %lu ns\n",
- __func__, delta);
- return -ETIME;
- }
-
- /* Please wake us this far in the future. */
- hcall(LHCALL_SET_CLOCKEVENT, delta, 0, 0, 0);
- return 0;
-}
-
-static int lguest_clockevent_shutdown(struct clock_event_device *evt)
-{
- /* A 0 argument shuts the clock down. */
- hcall(LHCALL_SET_CLOCKEVENT, 0, 0, 0, 0);
- return 0;
-}
-
-/* This describes our primitive timer chip. */
-static struct clock_event_device lguest_clockevent = {
- .name = "lguest",
- .features = CLOCK_EVT_FEAT_ONESHOT,
- .set_next_event = lguest_clockevent_set_next_event,
- .set_state_shutdown = lguest_clockevent_shutdown,
- .rating = INT_MAX,
- .mult = 1,
- .shift = 0,
- .min_delta_ns = LG_CLOCK_MIN_DELTA,
- .min_delta_ticks = LG_CLOCK_MIN_DELTA,
- .max_delta_ns = LG_CLOCK_MAX_DELTA,
- .max_delta_ticks = LG_CLOCK_MAX_DELTA,
-};
-
-/*
- * This is the Guest timer interrupt handler (hardware interrupt 0). We just
- * call the clockevent infrastructure and it does whatever needs doing.
- */
-static void lguest_time_irq(struct irq_desc *desc)
-{
- unsigned long flags;
-
- /* Don't interrupt us while this is running. */
- local_irq_save(flags);
- lguest_clockevent.event_handler(&lguest_clockevent);
- local_irq_restore(flags);
-}
-
-/*
- * At some point in the boot process, we get asked to set up our timing
- * infrastructure. The kernel doesn't expect timer interrupts before this, but
- * we cleverly initialized the "blocked_interrupts" field of "struct
- * lguest_data" so that timer interrupts were blocked until now.
- */
-static void lguest_time_init(void)
-{
- /* Set up the timer interrupt (0) to go to our simple timer routine */
- if (lguest_setup_irq(0) != 0)
- panic("Could not set up timer irq");
- irq_set_handler(0, lguest_time_irq);
-
- clocksource_register_hz(&lguest_clock, NSEC_PER_SEC);
-
- /* We can't set cpumask in the initializer: damn C limitations! Set it
- * here and register our timer device. */
- lguest_clockevent.cpumask = cpumask_of(0);
- clockevents_register_device(&lguest_clockevent);
-
- /* Finally, we unblock the timer interrupt. */
- clear_bit(0, lguest_data.blocked_interrupts);
-}
-
-/*
- * Miscellaneous bits and pieces.
- *
- * Here is an oddball collection of functions which the Guest needs for things
- * to work. They're pretty simple.
- */
-
-/*
- * The Guest needs to tell the Host what stack it expects traps to use. For
- * native hardware, this is part of the Task State Segment mentioned above in
- * lguest_load_tr_desc(), but to help hypervisors there's this special call.
- *
- * We tell the Host the segment we want to use (__KERNEL_DS is the kernel data
- * segment), the privilege level (we're privilege level 1, the Host is 0 and
- * will not tolerate us trying to use that), the stack pointer, and the number
- * of pages in the stack.
- */
-static void lguest_load_sp0(struct tss_struct *tss,
- struct thread_struct *thread)
-{
- lazy_hcall3(LHCALL_SET_STACK, __KERNEL_DS | 0x1, thread->sp0,
- THREAD_SIZE / PAGE_SIZE);
- tss->x86_tss.sp0 = thread->sp0;
-}
-
-/* Let's just say, I wouldn't do debugging under a Guest. */
-static unsigned long lguest_get_debugreg(int regno)
-{
- /* FIXME: Implement */
- return 0;
-}
-
-static void lguest_set_debugreg(int regno, unsigned long value)
-{
- /* FIXME: Implement */
-}
-
-/*
- * There are times when the kernel wants to make sure that no memory writes are
- * caught in the cache (that they've all reached real hardware devices). This
- * doesn't matter for the Guest which has virtual hardware.
- *
- * On the Pentium 4 and above, cpuid() indicates that the Cache Line Flush
- * (clflush) instruction is available and the kernel uses that. Otherwise, it
- * uses the older "Write Back and Invalidate Cache" (wbinvd) instruction.
- * Unlike clflush, wbinvd can only be run at privilege level 0. So we can
- * ignore clflush, but replace wbinvd.
- */
-static void lguest_wbinvd(void)
-{
-}
-
-/*
- * If the Guest expects to have an Advanced Programmable Interrupt Controller,
- * we play dumb by ignoring writes and returning 0 for reads. So it's no
- * longer Programmable nor Controlling anything, and I don't think 8 lines of
- * code qualifies for Advanced. It will also never interrupt anything. It
- * does, however, allow us to get through the Linux boot code.
- */
-#ifdef CONFIG_X86_LOCAL_APIC
-static void lguest_apic_write(u32 reg, u32 v)
-{
-}
-
-static u32 lguest_apic_read(u32 reg)
-{
- return 0;
-}
-
-static u64 lguest_apic_icr_read(void)
-{
- return 0;
-}
-
-static void lguest_apic_icr_write(u32 low, u32 id)
-{
- /* Warn to see if there's any stray references */
- WARN_ON(1);
-}
-
-static void lguest_apic_wait_icr_idle(void)
-{
- return;
-}
-
-static u32 lguest_apic_safe_wait_icr_idle(void)
-{
- return 0;
-}
-
-static void set_lguest_basic_apic_ops(void)
-{
- apic->read = lguest_apic_read;
- apic->write = lguest_apic_write;
- apic->icr_read = lguest_apic_icr_read;
- apic->icr_write = lguest_apic_icr_write;
- apic->wait_icr_idle = lguest_apic_wait_icr_idle;
- apic->safe_wait_icr_idle = lguest_apic_safe_wait_icr_idle;
-};
-#endif
-
-/* STOP! Until an interrupt comes in. */
-static void lguest_safe_halt(void)
-{
- hcall(LHCALL_HALT, 0, 0, 0, 0);
-}
-
-/*
- * The SHUTDOWN hypercall takes a string to describe what's happening, and
- * an argument which says whether this to restart (reboot) the Guest or not.
- *
- * Note that the Host always prefers that the Guest speak in physical addresses
- * rather than virtual addresses, so we use __pa() here.
- */
-static void lguest_power_off(void)
-{
- hcall(LHCALL_SHUTDOWN, __pa("Power down"),
- LGUEST_SHUTDOWN_POWEROFF, 0, 0);
-}
-
-/*
- * Panicing.
- *
- * Don't. But if you did, this is what happens.
- */
-static int lguest_panic(struct notifier_block *nb, unsigned long l, void *p)
-{
- hcall(LHCALL_SHUTDOWN, __pa(p), LGUEST_SHUTDOWN_POWEROFF, 0, 0);
- /* The hcall won't return, but to keep gcc happy, we're "done". */
- return NOTIFY_DONE;
-}
-
-static struct notifier_block paniced = {
- .notifier_call = lguest_panic
-};
-
-/* Setting up memory is fairly easy. */
-static __init char *lguest_memory_setup(void)
-{
- /*
- * The Linux bootloader header contains an "e820" memory map: the
- * Launcher populated the first entry with our memory limit.
- */
- e820__range_add(boot_params.e820_table[0].addr,
- boot_params.e820_table[0].size,
- boot_params.e820_table[0].type);
-
- /* This string is for the boot messages. */
- return "LGUEST";
-}
-
-/* Offset within PCI config space of BAR access capability. */
-static int console_cfg_offset = 0;
-static int console_access_cap;
-
-/* Set up so that we access off in bar0 (on bus 0, device 1, function 0) */
-static void set_cfg_window(u32 cfg_offset, u32 off)
-{
- write_pci_config_byte(0, 1, 0,
- cfg_offset + offsetof(struct virtio_pci_cap, bar),
- 0);
- write_pci_config(0, 1, 0,
- cfg_offset + offsetof(struct virtio_pci_cap, length),
- 4);
- write_pci_config(0, 1, 0,
- cfg_offset + offsetof(struct virtio_pci_cap, offset),
- off);
-}
-
-static void write_bar_via_cfg(u32 cfg_offset, u32 off, u32 val)
-{
- /*
- * We could set this up once, then leave it; nothing else in the *
- * kernel should touch these registers. But if it went wrong, that
- * would be a horrible bug to find.
- */
- set_cfg_window(cfg_offset, off);
- write_pci_config(0, 1, 0,
- cfg_offset + sizeof(struct virtio_pci_cap), val);
-}
-
-static void probe_pci_console(void)
-{
- u8 cap, common_cap = 0, device_cap = 0;
- u32 device_len;
-
- /* Avoid recursive printk into here. */
- console_cfg_offset = -1;
-
- if (!early_pci_allowed()) {
- printk(KERN_ERR "lguest: early PCI access not allowed!\n");
- return;
- }
-
- /* We expect a console PCI device at BUS0, slot 1. */
- if (read_pci_config(0, 1, 0, 0) != 0x10431AF4) {
- printk(KERN_ERR "lguest: PCI device is %#x!\n",
- read_pci_config(0, 1, 0, 0));
- return;
- }
-
- /* Find the capabilities we need (must be in bar0) */
- cap = read_pci_config_byte(0, 1, 0, PCI_CAPABILITY_LIST);
- while (cap) {
- u8 vndr = read_pci_config_byte(0, 1, 0, cap);
- if (vndr == PCI_CAP_ID_VNDR) {
- u8 type, bar;
-
- type = read_pci_config_byte(0, 1, 0,
- cap + offsetof(struct virtio_pci_cap, cfg_type));
- bar = read_pci_config_byte(0, 1, 0,
- cap + offsetof(struct virtio_pci_cap, bar));
-
- switch (type) {
- case VIRTIO_PCI_CAP_DEVICE_CFG:
- if (bar == 0)
- device_cap = cap;
- break;
- case VIRTIO_PCI_CAP_PCI_CFG:
- console_access_cap = cap;
- break;
- }
- }
- cap = read_pci_config_byte(0, 1, 0, cap + PCI_CAP_LIST_NEXT);
- }
- if (!device_cap || !console_access_cap) {
- printk(KERN_ERR "lguest: No caps (%u/%u/%u) in console!\n",
- common_cap, device_cap, console_access_cap);
- return;
- }
-
- /*
- * Note that we can't check features, until we've set the DRIVER
- * status bit. We don't want to do that until we have a real driver,
- * so we just check that the device-specific config has room for
- * emerg_wr. If it doesn't support VIRTIO_CONSOLE_F_EMERG_WRITE
- * it should ignore the access.
- */
- device_len = read_pci_config(0, 1, 0,
- device_cap + offsetof(struct virtio_pci_cap, length));
- if (device_len < (offsetof(struct virtio_console_config, emerg_wr)
- + sizeof(u32))) {
- printk(KERN_ERR "lguest: console missing emerg_wr field\n");
- return;
- }
-
- console_cfg_offset = read_pci_config(0, 1, 0,
- device_cap + offsetof(struct virtio_pci_cap, offset));
- printk(KERN_INFO "lguest: Console via virtio-pci emerg_wr\n");
-}
-
-/*
- * We will eventually use the virtio console device to produce console output,
- * but before that is set up we use the virtio PCI console's backdoor mmio
- * access and the "emergency" write facility (which is legal even before the
- * device is configured).
- */
-static __init int early_put_chars(u32 vtermno, const char *buf, int count)
-{
- /* If we couldn't find PCI console, forget it. */
- if (console_cfg_offset < 0)
- return count;
-
- if (unlikely(!console_cfg_offset)) {
- probe_pci_console();
- if (console_cfg_offset < 0)
- return count;
- }
-
- write_bar_via_cfg(console_access_cap,
- console_cfg_offset
- + offsetof(struct virtio_console_config, emerg_wr),
- buf[0]);
- return 1;
-}
-
-/*
- * Rebooting also tells the Host we're finished, but the RESTART flag tells the
- * Launcher to reboot us.
- */
-static void lguest_restart(char *reason)
-{
- hcall(LHCALL_SHUTDOWN, __pa(reason), LGUEST_SHUTDOWN_RESTART, 0, 0);
-}
-
-/*G:050
- * Patching (Powerfully Placating Performance Pedants)
- *
- * We have already seen that pv_ops structures let us replace simple native
- * instructions with calls to the appropriate back end all throughout the
- * kernel. This allows the same kernel to run as a Guest and as a native
- * kernel, but it's slow because of all the indirect branches.
- *
- * Remember that David Wheeler quote about "Any problem in computer science can
- * be solved with another layer of indirection"? The rest of that quote is
- * "... But that usually will create another problem." This is the first of
- * those problems.
- *
- * Our current solution is to allow the paravirt back end to optionally patch
- * over the indirect calls to replace them with something more efficient. We
- * patch two of the simplest of the most commonly called functions: disable
- * interrupts and save interrupts. We usually have 6 or 10 bytes to patch
- * into: the Guest versions of these operations are small enough that we can
- * fit comfortably.
- *
- * First we need assembly templates of each of the patchable Guest operations,
- * and these are in head_32.S.
- */
-
-/*G:060 We construct a table from the assembler templates: */
-static const struct lguest_insns
-{
- const char *start, *end;
-} lguest_insns[] = {
- [PARAVIRT_PATCH(pv_irq_ops.irq_disable)] = { lgstart_cli, lgend_cli },
- [PARAVIRT_PATCH(pv_irq_ops.save_fl)] = { lgstart_pushf, lgend_pushf },
-};
-
-/*
- * Now our patch routine is fairly simple (based on the native one in
- * paravirt.c). If we have a replacement, we copy it in and return how much of
- * the available space we used.
- */
-static unsigned lguest_patch(u8 type, u16 clobber, void *ibuf,
- unsigned long addr, unsigned len)
-{
- unsigned int insn_len;
-
- /* Don't do anything special if we don't have a replacement */
- if (type >= ARRAY_SIZE(lguest_insns) || !lguest_insns[type].start)
- return paravirt_patch_default(type, clobber, ibuf, addr, len);
-
- insn_len = lguest_insns[type].end - lguest_insns[type].start;
-
- /* Similarly if it can't fit (doesn't happen, but let's be thorough). */
- if (len < insn_len)
- return paravirt_patch_default(type, clobber, ibuf, addr, len);
-
- /* Copy in our instructions. */
- memcpy(ibuf, lguest_insns[type].start, insn_len);
- return insn_len;
-}
-
-/*G:029
- * Once we get to lguest_init(), we know we're a Guest. The various
- * pv_ops structures in the kernel provide points for (almost) every routine we
- * have to override to avoid privileged instructions.
- */
-__init void lguest_init(void)
-{
- /* We're under lguest. */
- pv_info.name = "lguest";
- /* We're running at privilege level 1, not 0 as normal. */
- pv_info.kernel_rpl = 1;
- /* Everyone except Xen runs with this set. */
- pv_info.shared_kernel_pmd = 1;
-
- /*
- * We set up all the lguest overrides for sensitive operations. These
- * are detailed with the operations themselves.
- */
-
- /* Interrupt-related operations */
- pv_irq_ops.save_fl = PV_CALLEE_SAVE(lguest_save_fl);
- pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(lg_restore_fl);
- pv_irq_ops.irq_disable = PV_CALLEE_SAVE(lguest_irq_disable);
- pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(lg_irq_enable);
- pv_irq_ops.safe_halt = lguest_safe_halt;
-
- /* Setup operations */
- pv_init_ops.patch = lguest_patch;
-
- /* Intercepts of various CPU instructions */
- pv_cpu_ops.load_gdt = lguest_load_gdt;
- pv_cpu_ops.cpuid = lguest_cpuid;
- pv_cpu_ops.load_idt = lguest_load_idt;
- pv_cpu_ops.iret = lguest_iret;
- pv_cpu_ops.load_sp0 = lguest_load_sp0;
- pv_cpu_ops.load_tr_desc = lguest_load_tr_desc;
- pv_cpu_ops.set_ldt = lguest_set_ldt;
- pv_cpu_ops.load_tls = lguest_load_tls;
- pv_cpu_ops.get_debugreg = lguest_get_debugreg;
- pv_cpu_ops.set_debugreg = lguest_set_debugreg;
- pv_cpu_ops.read_cr0 = lguest_read_cr0;
- pv_cpu_ops.write_cr0 = lguest_write_cr0;
- pv_cpu_ops.read_cr4 = lguest_read_cr4;
- pv_cpu_ops.write_cr4 = lguest_write_cr4;
- pv_cpu_ops.write_gdt_entry = lguest_write_gdt_entry;
- pv_cpu_ops.write_idt_entry = lguest_write_idt_entry;
- pv_cpu_ops.wbinvd = lguest_wbinvd;
- pv_cpu_ops.start_context_switch = paravirt_start_context_switch;
- pv_cpu_ops.end_context_switch = lguest_end_context_switch;
-
- /* Pagetable management */
- pv_mmu_ops.write_cr3 = lguest_write_cr3;
- pv_mmu_ops.flush_tlb_user = lguest_flush_tlb_user;
- pv_mmu_ops.flush_tlb_single = lguest_flush_tlb_single;
- pv_mmu_ops.flush_tlb_kernel = lguest_flush_tlb_kernel;
- pv_mmu_ops.set_pte = lguest_set_pte;
- pv_mmu_ops.set_pte_at = lguest_set_pte_at;
- pv_mmu_ops.set_pmd = lguest_set_pmd;
-#ifdef CONFIG_X86_PAE
- pv_mmu_ops.set_pte_atomic = lguest_set_pte_atomic;
- pv_mmu_ops.pte_clear = lguest_pte_clear;
- pv_mmu_ops.pmd_clear = lguest_pmd_clear;
- pv_mmu_ops.set_pud = lguest_set_pud;
-#endif
- pv_mmu_ops.read_cr2 = lguest_read_cr2;
- pv_mmu_ops.read_cr3 = lguest_read_cr3;
- pv_mmu_ops.lazy_mode.enter = paravirt_enter_lazy_mmu;
- pv_mmu_ops.lazy_mode.leave = lguest_leave_lazy_mmu_mode;
- pv_mmu_ops.lazy_mode.flush = paravirt_flush_lazy_mmu;
- pv_mmu_ops.pte_update = lguest_pte_update;
-
-#ifdef CONFIG_X86_LOCAL_APIC
- /* APIC read/write intercepts */
- set_lguest_basic_apic_ops();
-#endif
-
- x86_init.resources.memory_setup = lguest_memory_setup;
- x86_init.irqs.intr_init = lguest_init_IRQ;
- x86_init.timers.timer_init = lguest_time_init;
- x86_platform.calibrate_tsc = lguest_tsc_khz;
- x86_platform.get_wallclock = lguest_get_wallclock;
-
- /*
- * Now is a good time to look at the implementations of these functions
- * before returning to the rest of lguest_init().
- */
-
- /*G:070
- * Now we've seen all the paravirt_ops, we return to
- * lguest_init() where the rest of the fairly chaotic boot setup
- * occurs.
- */
-
- /*
- * The stack protector is a weird thing where gcc places a canary
- * value on the stack and then checks it on return. This file is
- * compiled with -fno-stack-protector it, so we got this far without
- * problems. The value of the canary is kept at offset 20 from the
- * %gs register, so we need to set that up before calling C functions
- * in other files.
- */
- setup_stack_canary_segment(0);
-
- /*
- * We could just call load_stack_canary_segment(), but we might as well
- * call switch_to_new_gdt() which loads the whole table and sets up the
- * per-cpu segment descriptor register %fs as well.
- */
- switch_to_new_gdt(0);
-
- /*
- * The Host<->Guest Switcher lives at the top of our address space, and
- * the Host told us how big it is when we made LGUEST_INIT hypercall:
- * it put the answer in lguest_data.reserve_mem
- */
- reserve_top_address(lguest_data.reserve_mem);
-
- /* Hook in our special panic hypercall code. */
- atomic_notifier_chain_register(&panic_notifier_list, &paniced);
-
- /*
- * This is messy CPU setup stuff which the native boot code does before
- * start_kernel, so we have to do, too:
- */
- cpu_detect(&new_cpu_data);
- /* head.S usually sets up the first capability word, so do it here. */
- new_cpu_data.x86_capability[CPUID_1_EDX] = cpuid_edx(1);
-
- /* Math is always hard! */
- set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU);
-
- /* We don't have features. We have puppies! Puppies! */
-#ifdef CONFIG_X86_MCE
- mca_cfg.disabled = true;
-#endif
-#ifdef CONFIG_ACPI
- acpi_disabled = 1;
-#endif
-
- /*
- * We set the preferred console to "hvc". This is the "hypervisor
- * virtual console" driver written by the PowerPC people, which we also
- * adapted for lguest's use.
- */
- add_preferred_console("hvc", 0, NULL);
-
- /* Register our very early console. */
- virtio_cons_early_init(early_put_chars);
-
- /* Don't let ACPI try to control our PCI interrupts. */
- disable_acpi();
-
- /* We control them ourselves, by overriding these two hooks. */
- pcibios_enable_irq = lguest_enable_irq;
- pcibios_disable_irq = lguest_disable_irq;
-
- /*
- * Last of all, we set the power management poweroff hook to point to
- * the Guest routine to power off, and the reboot hook to our restart
- * routine.
- */
- pm_power_off = lguest_power_off;
- machine_ops.restart = lguest_restart;
-
- /*
- * Now we're set up, call i386_start_kernel() in head32.c and we proceed
- * to boot as normal. It never returns.
- */
- i386_start_kernel();
-}
-/*
- * This marks the end of stage II of our journey, The Guest.
- *
- * It is now time for us to explore the layer of virtual drivers and complete
- * our understanding of the Guest in "make Drivers".
- */
diff --git a/arch/x86/lguest/head_32.S b/arch/x86/lguest/head_32.S
deleted file mode 100644
index d5ae63f5ec5d..000000000000
--- a/arch/x86/lguest/head_32.S
+++ /dev/null
@@ -1,192 +0,0 @@
-#include <linux/linkage.h>
-#include <linux/lguest.h>
-#include <asm/lguest_hcall.h>
-#include <asm/asm-offsets.h>
-#include <asm/thread_info.h>
-#include <asm/processor-flags.h>
-
-/*G:020
-
- * Our story starts with the bzImage: booting starts at startup_32 in
- * arch/x86/boot/compressed/head_32.S. This merely uncompresses the real
- * kernel in place and then jumps into it: startup_32 in
- * arch/x86/kernel/head_32.S. Both routines expects a boot header in the %esi
- * register, which is created by the bootloader (the Launcher in our case).
- *
- * The startup_32 function does very little: it clears the uninitialized global
- * C variables which we expect to be zero (ie. BSS) and then copies the boot
- * header and kernel command line somewhere safe, and populates some initial
- * page tables. Finally it checks the 'hardware_subarch' field. This was
- * introduced in 2.6.24 for lguest and Xen: if it's set to '1' (lguest's
- * assigned number), then it calls us here.
- *
- * WARNING: be very careful here! We're running at addresses equal to physical
- * addresses (around 0), not above PAGE_OFFSET as most code expects
- * (eg. 0xC0000000). Jumps are relative, so they're OK, but we can't touch any
- * data without remembering to subtract __PAGE_OFFSET!
- *
- * The .section line puts this code in .init.text so it will be discarded after
- * boot.
- */
-.section .init.text, "ax", @progbits
-ENTRY(lguest_entry)
- /*
- * We make the "initialization" hypercall now to tell the Host where
- * our lguest_data struct is.
- */
- movl $LHCALL_LGUEST_INIT, %eax
- movl $lguest_data - __PAGE_OFFSET, %ebx
- int $LGUEST_TRAP_ENTRY
-
- /* Now turn our pagetables on; setup by arch/x86/kernel/head_32.S. */
- movl $LHCALL_NEW_PGTABLE, %eax
- movl $(initial_page_table - __PAGE_OFFSET), %ebx
- int $LGUEST_TRAP_ENTRY
-
- /* Set up the initial stack so we can run C code. */
- movl $(init_thread_union+THREAD_SIZE),%esp
-
- /* Jumps are relative: we're running __PAGE_OFFSET too low. */
- jmp lguest_init+__PAGE_OFFSET
-
-/*G:055
- * We create a macro which puts the assembler code between lgstart_ and lgend_
- * markers. These templates are put in the .text section: they can't be
- * discarded after boot as we may need to patch modules, too.
- */
-.text
-#define LGUEST_PATCH(name, insns...) \
- lgstart_##name: insns; lgend_##name:; \
- .globl lgstart_##name; .globl lgend_##name
-
-LGUEST_PATCH(cli, movl $0, lguest_data+LGUEST_DATA_irq_enabled)
-LGUEST_PATCH(pushf, movl lguest_data+LGUEST_DATA_irq_enabled, %eax)
-
-/*G:033
- * But using those wrappers is inefficient (we'll see why that doesn't matter
- * for save_fl and irq_disable later). If we write our routines carefully in
- * assembler, we can avoid clobbering any registers and avoid jumping through
- * the wrapper functions.
- *
- * I skipped over our first piece of assembler, but this one is worth studying
- * in a bit more detail so I'll describe in easy stages. First, the routine to
- * enable interrupts:
- */
-ENTRY(lg_irq_enable)
- /*
- * The reverse of irq_disable, this sets lguest_data.irq_enabled to
- * X86_EFLAGS_IF (ie. "Interrupts enabled").
- */
- movl $X86_EFLAGS_IF, lguest_data+LGUEST_DATA_irq_enabled
- /*
- * But now we need to check if the Host wants to know: there might have
- * been interrupts waiting to be delivered, in which case it will have
- * set lguest_data.irq_pending to X86_EFLAGS_IF. If it's not zero, we
- * jump to send_interrupts, otherwise we're done.
- */
- cmpl $0, lguest_data+LGUEST_DATA_irq_pending
- jnz send_interrupts
- /*
- * One cool thing about x86 is that you can do many things without using
- * a register. In this case, the normal path hasn't needed to save or
- * restore any registers at all!
- */
- ret
-send_interrupts:
- /*
- * OK, now we need a register: eax is used for the hypercall number,
- * which is LHCALL_SEND_INTERRUPTS.
- *
- * We used not to bother with this pending detection at all, which was
- * much simpler. Sooner or later the Host would realize it had to
- * send us an interrupt. But that turns out to make performance 7
- * times worse on a simple tcp benchmark. So now we do this the hard
- * way.
- */
- pushl %eax
- movl $LHCALL_SEND_INTERRUPTS, %eax
- /* This is the actual hypercall trap. */
- int $LGUEST_TRAP_ENTRY
- /* Put eax back the way we found it. */
- popl %eax
- ret
-
-/*
- * Finally, the "popf" or "restore flags" routine. The %eax register holds the
- * flags (in practice, either X86_EFLAGS_IF or 0): if it's X86_EFLAGS_IF we're
- * enabling interrupts again, if it's 0 we're leaving them off.
- */
-ENTRY(lg_restore_fl)
- /* This is just "lguest_data.irq_enabled = flags;" */
- movl %eax, lguest_data+LGUEST_DATA_irq_enabled
- /*
- * Now, if the %eax value has enabled interrupts and
- * lguest_data.irq_pending is set, we want to tell the Host so it can
- * deliver any outstanding interrupts. Fortunately, both values will
- * be X86_EFLAGS_IF (ie. 512) in that case, and the "testl"
- * instruction will AND them together for us. If both are set, we
- * jump to send_interrupts.
- */
- testl lguest_data+LGUEST_DATA_irq_pending, %eax
- jnz send_interrupts
- /* Again, the normal path has used no extra registers. Clever, huh? */
- ret
-/*:*/
-
-/* These demark the EIP where host should never deliver interrupts. */
-.global lguest_noirq_iret
-
-/*M:004
- * When the Host reflects a trap or injects an interrupt into the Guest, it
- * sets the eflags interrupt bit on the stack based on lguest_data.irq_enabled,
- * so the Guest iret logic does the right thing when restoring it. However,
- * when the Host sets the Guest up for direct traps, such as system calls, the
- * processor is the one to push eflags onto the stack, and the interrupt bit
- * will be 1 (in reality, interrupts are always enabled in the Guest).
- *
- * This turns out to be harmless: the only trap which should happen under Linux
- * with interrupts disabled is Page Fault (due to our lazy mapping of vmalloc
- * regions), which has to be reflected through the Host anyway. If another
- * trap *does* go off when interrupts are disabled, the Guest will panic, and
- * we'll never get to this iret!
-:*/
-
-/*G:045
- * There is one final paravirt_op that the Guest implements, and glancing at it
- * you can see why I left it to last. It's *cool*! It's in *assembler*!
- *
- * The "iret" instruction is used to return from an interrupt or trap. The
- * stack looks like this:
- * old address
- * old code segment & privilege level
- * old processor flags ("eflags")
- *
- * The "iret" instruction pops those values off the stack and restores them all
- * at once. The only problem is that eflags includes the Interrupt Flag which
- * the Guest can't change: the CPU will simply ignore it when we do an "iret".
- * So we have to copy eflags from the stack to lguest_data.irq_enabled before
- * we do the "iret".
- *
- * There are two problems with this: firstly, we can't clobber any registers
- * and secondly, the whole thing needs to be atomic. The first problem
- * is solved by using "push memory"/"pop memory" instruction pair for copying.
- *
- * The second is harder: copying eflags to lguest_data.irq_enabled will turn
- * interrupts on before we're finished, so we could be interrupted before we
- * return to userspace or wherever. Our solution to this is to tell the
- * Host that it is *never* to interrupt us there, even if interrupts seem to be
- * enabled. (It's not necessary to protect pop instruction, since
- * data gets updated only after it completes, so we only need to protect
- * one instruction, iret).
- */
-ENTRY(lguest_iret)
- pushl 2*4(%esp)
- /*
- * Note the %ss: segment prefix here. Normal data accesses use the
- * "ds" segment, but that will have already been restored for whatever
- * we're returning to (such as userspace): we can't trust it. The %ss:
- * prefix makes sure we use the stack segment, which is still valid.
- */
- popl %ss:lguest_data+LGUEST_DATA_irq_enabled
-lguest_noirq_iret:
- iret