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authorSean Christopherson <sean.j.christopherson@intel.com>2019-07-19 13:41:08 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2019-09-25 15:30:09 +0200
commit6e2020977e3e692a8bb31258c1f8251521f4fdb7 (patch)
tree19b899e36297b4aa35daeb68417e7a49a3346cc3 /arch
parent52a9fcbc73a30375cad8d9e7b519e1ad97b0880a (diff)
downloadlinux-6e2020977e3e692a8bb31258c1f8251521f4fdb7.tar.gz
KVM: VMX: Add error handling to VMREAD helper
Now that VMREAD flows require a taken branch, courtesy of commit 3901336ed9887 ("x86/kvm: Don't call kvm_spurious_fault() from .fixup") bite the bullet and add full error handling to VMREAD, i.e. replace the JMP added by __ex()/____kvm_handle_fault_on_reboot() with a hinted Jcc. To minimize the code footprint, add a helper function, vmread_error(), to handle both faults and failures so that the inline flow has a single CALL. Acked-by: Paolo Bonzini <pbonzini@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/vmx/ops.h21
-rw-r--r--arch/x86/kvm/vmx/vmx.c8
2 files changed, 25 insertions, 4 deletions
diff --git a/arch/x86/kvm/vmx/ops.h b/arch/x86/kvm/vmx/ops.h
index 79e25d49d4d9..45eaedee2ac0 100644
--- a/arch/x86/kvm/vmx/ops.h
+++ b/arch/x86/kvm/vmx/ops.h
@@ -11,9 +11,8 @@
#include "vmcs.h"
#define __ex(x) __kvm_handle_fault_on_reboot(x)
-#define __ex_clear(x, reg) \
- ____kvm_handle_fault_on_reboot(x, "xor " reg ", " reg)
+asmlinkage void vmread_error(unsigned long field, bool fault);
void vmwrite_error(unsigned long field, unsigned long value);
void vmclear_error(struct vmcs *vmcs, u64 phys_addr);
void vmptrld_error(struct vmcs *vmcs, u64 phys_addr);
@@ -68,8 +67,22 @@ static __always_inline unsigned long __vmcs_readl(unsigned long field)
{
unsigned long value;
- asm volatile (__ex_clear("vmread %1, %0", "%k0")
- : "=r"(value) : "r"(field));
+ asm volatile("1: vmread %2, %1\n\t"
+ ".byte 0x3e\n\t" /* branch taken hint */
+ "ja 3f\n\t"
+ "mov %2, %%" _ASM_ARG1 "\n\t"
+ "xor %%" _ASM_ARG2 ", %%" _ASM_ARG2 "\n\t"
+ "2: call vmread_error\n\t"
+ "xor %k1, %k1\n\t"
+ "3:\n\t"
+
+ ".pushsection .fixup, \"ax\"\n\t"
+ "4: mov %2, %%" _ASM_ARG1 "\n\t"
+ "mov $1, %%" _ASM_ARG2 "\n\t"
+ "jmp 2b\n\t"
+ ".popsection\n\t"
+ _ASM_EXTABLE(1b, 4b)
+ : ASM_CALL_CONSTRAINT, "=r"(value) : "r"(field) : "cc");
return value;
}
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 52c7614b5ecd..1852706e6acc 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -349,6 +349,14 @@ do { \
pr_warn_ratelimited(fmt); \
} while (0)
+asmlinkage void vmread_error(unsigned long field, bool fault)
+{
+ if (fault)
+ kvm_spurious_fault();
+ else
+ vmx_insn_failed("kvm: vmread failed: field=%lx\n", field);
+}
+
noinline void vmwrite_error(unsigned long field, unsigned long value)
{
vmx_insn_failed("kvm: vmwrite failed: field=%lx val=%lx err=%d\n",