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Diffstat (limited to 'arch/x86/kvm/mmu.c')
-rw-r--r--arch/x86/kvm/mmu.c26
1 files changed, 15 insertions, 11 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a282321329b5..e24ea7067373 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1853,11 +1853,6 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
return kvm_handle_hva_range(kvm, hva, hva + 1, data, handler);
}
-int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
-{
- return kvm_handle_hva(kvm, hva, 0, kvm_unmap_rmapp);
-}
-
int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end)
{
return kvm_handle_hva_range(kvm, start, end, 0, kvm_unmap_rmapp);
@@ -5217,7 +5212,7 @@ static int make_mmu_pages_available(struct kvm_vcpu *vcpu)
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 = 0;
enum emulation_result er;
bool direct = vcpu->arch.mmu.direct_map;
@@ -5230,10 +5225,8 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u64 error_code,
r = RET_PF_INVALID;
if (unlikely(error_code & PFERR_RSVD_MASK)) {
r = handle_mmio_page_fault(vcpu, cr2, direct);
- if (r == RET_PF_EMULATE) {
- emulation_type = 0;
+ if (r == RET_PF_EMULATE)
goto emulate;
- }
}
if (r == RET_PF_INVALID) {
@@ -5260,8 +5253,19 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u64 error_code,
return 1;
}
- if (mmio_info_in_cache(vcpu, cr2, direct))
- emulation_type = 0;
+ /*
+ * vcpu->arch.mmu.page_fault returned RET_PF_EMULATE, but we can still
+ * optimistically try to just unprotect the page and let the processor
+ * re-execute the instruction that caused the page fault. Do not allow
+ * retrying MMIO emulation, as it's not only pointless but could also
+ * cause us to enter an infinite loop because the processor will keep
+ * faulting on the non-existent MMIO address. Retrying an instruction
+ * from a nested guest is also pointless and dangerous as we are only
+ * explicitly shadowing L1's page tables, i.e. unprotecting something
+ * for L1 isn't going to magically fix whatever issue cause L2 to fail.
+ */
+ if (!mmio_info_in_cache(vcpu, cr2, direct) && !is_guest_mode(vcpu))
+ emulation_type = EMULTYPE_ALLOW_RETRY;
emulate:
/*
* On AMD platforms, under certain conditions insn_len may be zero on #NPF.
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