On 08/30/2011 05:35 AM, Xiao Guangrong wrote:
If the emulation is caused by #PF and it is non-page_table writing instruction,
it means the VM-EXIT is caused by shadow page protected, we can zap the shadow
page and retry this instruction directly
The idea is from Avi
int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len);
+bool page_table_writing_insn(struct x86_emulate_ctxt *ctxt);
Please use the usual x86_ prefix used in the emulator interface.
@@ -3720,10 +3721,18 @@ void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
kvm_mmu_commit_zap_page(vcpu->kvm,&invalid_list);
}
+static bool is_mmio_page_fault(struct kvm_vcpu *vcpu, gva_t addr)
+{
+ if (vcpu->arch.mmu.direct_map || mmu_is_nested(vcpu))
+ return vcpu_match_mmio_gpa(vcpu, addr);
+
+ return vcpu_match_mmio_gva(vcpu, addr);
+}
+
int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code,
void *insn, int insn_len)
{
- int r;
+ int r, emulation_type = EMULTYPE_RETRY;
enum emulation_result er;
r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code, false);
@@ -3735,7 +3744,10 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2,
u32 error_code,
goto out;
}
- er = x86_emulate_instruction(vcpu, cr2, 0, insn, insn_len);
+ if (is_mmio_page_fault(vcpu, cr2))
+ emulation_type = 0;
+
+ er = x86_emulate_instruction(vcpu, cr2, emulation_type, insn, insn_len);
switch (er) {
case EMULATE_DONE:
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6b37f18..1afe59e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4814,6 +4814,50 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu,
gva_t gva)
return false;
}
+static bool retry_instruction(struct x86_emulate_ctxt *ctxt,
+ unsigned long cr2, int emulation_type)
+{
+ if (!vcpu->arch.mmu.direct_map&& !mmu_is_nested(vcpu))
+ gpa = kvm_mmu_gva_to_gpa_write(vcpu, cr2, NULL);
If mmu_is_nested() cr2 is an ngpa, we have to translate it to a gpa, no?
btw, I don't see mmu.direct_map initialized for nested npt?
+
+ kvm_mmu_unprotect_page(vcpu->kvm, gpa>> PAGE_SHIFT);
+
+ return true;
+}
+
int x86_emulate_instruction(struct kvm_vcpu *vcpu,
unsigned long cr2,
int emulation_type,
@@ -4855,6 +4899,9 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu,
return EMULATE_DONE;
}
+ if (retry_instruction(ctxt, cr2, emulation_type))
+ return EMULATE_DONE;
+
/* this is needed for vmware backdoor interface to work since it
changes registers values during IO operation */
if (vcpu->arch.emulate_regs_need_sync_from_vcpu) {
--
error compiling committee.c: too many arguments to function
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