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Diffstat (limited to 'drivers/lguest/hypercalls.c')
-rw-r--r--drivers/lguest/hypercalls.c192
1 files changed, 192 insertions, 0 deletions
diff --git a/drivers/lguest/hypercalls.c b/drivers/lguest/hypercalls.c
new file mode 100644
index 00000000000..ea52ca451f7
--- /dev/null
+++ b/drivers/lguest/hypercalls.c
@@ -0,0 +1,192 @@
+/* Actual hypercalls, which allow guests to actually do something.
+ Copyright (C) 2006 Rusty Russell 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. 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+*/
+#include <linux/uaccess.h>
+#include <linux/syscalls.h>
+#include <linux/mm.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <irq_vectors.h>
+#include "lg.h"
+
+static void do_hcall(struct lguest *lg, struct lguest_regs *regs)
+{
+ switch (regs->eax) {
+ case LHCALL_FLUSH_ASYNC:
+ break;
+ case LHCALL_LGUEST_INIT:
+ kill_guest(lg, "already have lguest_data");
+ break;
+ case LHCALL_CRASH: {
+ char msg[128];
+ lgread(lg, msg, regs->edx, sizeof(msg));
+ msg[sizeof(msg)-1] = '\0';
+ kill_guest(lg, "CRASH: %s", msg);
+ break;
+ }
+ case LHCALL_FLUSH_TLB:
+ if (regs->edx)
+ guest_pagetable_clear_all(lg);
+ else
+ guest_pagetable_flush_user(lg);
+ break;
+ case LHCALL_GET_WALLCLOCK: {
+ struct timespec ts;
+ ktime_get_real_ts(&ts);
+ regs->eax = ts.tv_sec;
+ break;
+ }
+ case LHCALL_BIND_DMA:
+ regs->eax = bind_dma(lg, regs->edx, regs->ebx,
+ regs->ecx >> 8, regs->ecx & 0xFF);
+ break;
+ case LHCALL_SEND_DMA:
+ send_dma(lg, regs->edx, regs->ebx);
+ break;
+ case LHCALL_LOAD_GDT:
+ load_guest_gdt(lg, regs->edx, regs->ebx);
+ break;
+ case LHCALL_LOAD_IDT_ENTRY:
+ load_guest_idt_entry(lg, regs->edx, regs->ebx, regs->ecx);
+ break;
+ case LHCALL_NEW_PGTABLE:
+ guest_new_pagetable(lg, regs->edx);
+ break;
+ case LHCALL_SET_STACK:
+ guest_set_stack(lg, regs->edx, regs->ebx, regs->ecx);
+ break;
+ case LHCALL_SET_PTE:
+ guest_set_pte(lg, regs->edx, regs->ebx, mkgpte(regs->ecx));
+ break;
+ case LHCALL_SET_PMD:
+ guest_set_pmd(lg, regs->edx, regs->ebx);
+ break;
+ case LHCALL_LOAD_TLS:
+ guest_load_tls(lg, regs->edx);
+ break;
+ case LHCALL_SET_CLOCKEVENT:
+ guest_set_clockevent(lg, regs->edx);
+ break;
+ case LHCALL_TS:
+ lg->ts = regs->edx;
+ break;
+ case LHCALL_HALT:
+ lg->halted = 1;
+ break;
+ default:
+ kill_guest(lg, "Bad hypercall %li\n", regs->eax);
+ }
+}
+
+/* We always do queued calls before actual hypercall. */
+static void do_async_hcalls(struct lguest *lg)
+{
+ unsigned int i;
+ u8 st[LHCALL_RING_SIZE];
+
+ if (copy_from_user(&st, &lg->lguest_data->hcall_status, sizeof(st)))
+ return;
+
+ for (i = 0; i < ARRAY_SIZE(st); i++) {
+ struct lguest_regs regs;
+ unsigned int n = lg->next_hcall;
+
+ if (st[n] == 0xFF)
+ break;
+
+ if (++lg->next_hcall == LHCALL_RING_SIZE)
+ lg->next_hcall = 0;
+
+ if (get_user(regs.eax, &lg->lguest_data->hcalls[n].eax)
+ || get_user(regs.edx, &lg->lguest_data->hcalls[n].edx)
+ || get_user(regs.ecx, &lg->lguest_data->hcalls[n].ecx)
+ || get_user(regs.ebx, &lg->lguest_data->hcalls[n].ebx)) {
+ kill_guest(lg, "Fetching async hypercalls");
+ break;
+ }
+
+ do_hcall(lg, &regs);
+ if (put_user(0xFF, &lg->lguest_data->hcall_status[n])) {
+ kill_guest(lg, "Writing result for async hypercall");
+ break;
+ }
+
+ if (lg->dma_is_pending)
+ break;
+ }
+}
+
+static void initialize(struct lguest *lg)
+{
+ u32 tsc_speed;
+
+ if (lg->regs->eax != LHCALL_LGUEST_INIT) {
+ kill_guest(lg, "hypercall %li before LGUEST_INIT",
+ lg->regs->eax);
+ return;
+ }
+
+ /* We only tell the guest to use the TSC if it's reliable. */
+ if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) && !check_tsc_unstable())
+ tsc_speed = tsc_khz;
+ else
+ tsc_speed = 0;
+
+ lg->lguest_data = (struct lguest_data __user *)lg->regs->edx;
+ /* We check here so we can simply copy_to_user/from_user */
+ if (!lguest_address_ok(lg, lg->regs->edx, sizeof(*lg->lguest_data))) {
+ kill_guest(lg, "bad guest page %p", lg->lguest_data);
+ return;
+ }
+ if (get_user(lg->noirq_start, &lg->lguest_data->noirq_start)
+ || get_user(lg->noirq_end, &lg->lguest_data->noirq_end)
+ /* We reserve the top pgd entry. */
+ || put_user(4U*1024*1024, &lg->lguest_data->reserve_mem)
+ || put_user(tsc_speed, &lg->lguest_data->tsc_khz)
+ || put_user(lg->guestid, &lg->lguest_data->guestid))
+ kill_guest(lg, "bad guest page %p", lg->lguest_data);
+
+ /* This is the one case where the above accesses might have
+ * been the first write to a Guest page. This may have caused
+ * a copy-on-write fault, but the Guest might be referring to
+ * the old (read-only) page. */
+ guest_pagetable_clear_all(lg);
+}
+
+/* Even if we go out to userspace and come back, we don't want to do
+ * the hypercall again. */
+static void clear_hcall(struct lguest *lg)
+{
+ lg->regs->trapnum = 255;
+}
+
+void do_hypercalls(struct lguest *lg)
+{
+ if (unlikely(!lg->lguest_data)) {
+ if (lg->regs->trapnum == LGUEST_TRAP_ENTRY) {
+ initialize(lg);
+ clear_hcall(lg);
+ }
+ return;
+ }
+
+ do_async_hcalls(lg);
+ if (!lg->dma_is_pending && lg->regs->trapnum == LGUEST_TRAP_ENTRY) {
+ do_hcall(lg, lg->regs);
+ clear_hcall(lg);
+ }
+}