From: Sean Christopherson <sean.j.christopherson@intel.com>
Date: Thu, 23 Aug 2018 13:56:48 -0700
Subject: KVM: x86: Invert emulation re-execute behavior to make it opt-in
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Git-commit: 8065dbd1ee0ef04321d80da7999b4f0086e0a407
Patch-mainline: v4.19-rc3
References: bsc#1106240
Re-execution of an instruction after emulation decode failure is
intended to be used only when emulating shadow page accesses. Invert
the flag to make allowing re-execution opt-in since that behavior is
by far in the minority.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/include/asm/kvm_host.h | 8 +++-----
arch/x86/kvm/mmu.c | 2 +-
arch/x86/kvm/x86.c | 2 +-
3 files changed, 5 insertions(+), 7 deletions(-)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1183,15 +1183,14 @@ enum emulation_result {
#define EMULTYPE_TRAP_UD (1 << 1)
#define EMULTYPE_SKIP (1 << 2)
#define EMULTYPE_RETRY (1 << 3)
-#define EMULTYPE_NO_REEXECUTE (1 << 4)
+#define EMULTYPE_ALLOW_REEXECUTE (1 << 4)
int x86_emulate_instruction(struct kvm_vcpu *vcpu, unsigned long cr2,
int emulation_type, void *insn, int insn_len);
static inline int emulate_instruction(struct kvm_vcpu *vcpu,
int emulation_type)
{
- return x86_emulate_instruction(vcpu, 0,
- emulation_type | EMULTYPE_NO_REEXECUTE, NULL, 0);
+ return x86_emulate_instruction(vcpu, 0, emulation_type, NULL, 0);
}
void kvm_enable_efer_bits(u64);
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -4919,7 +4919,7 @@ static int make_mmu_pages_available(stru
int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u64 error_code,
void *insn, int insn_len)
{
- int r, emulation_type = EMULTYPE_RETRY;
+ int r, emulation_type = EMULTYPE_RETRY | EMULTYPE_ALLOW_REEXECUTE;
enum emulation_result er;
bool direct = vcpu->arch.mmu.direct_map;
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5499,7 +5499,7 @@ static bool reexecute_instruction(struct
gpa_t gpa = cr2;
kvm_pfn_t pfn;
- if (emulation_type & EMULTYPE_NO_REEXECUTE)
+ if (!(emulation_type & EMULTYPE_ALLOW_REEXECUTE))
return false;
if (!vcpu->arch.mmu.direct_map) {