[PATCH v2] KVM: MMU: Fix guest stuck during boot due to read/write emulation against GVA

[Wanpeng Li]

From: Wanpeng Li 

Commit c016004494b0 (KVM: x86: Avoid guest page table walk when gpa_available 
is set) avoids the page table walk when cr2 has already contained a valid GPA. 
However, that is not the truth if ept == 0 and shadow page table is used. In 
this scenario cr2 can just contains a valid GVA. The commit results in guest 
stuck during boot due to read/write emulation against GVA instead of GPA of 
the guest.

This patch fixes it by setting the gpa_available flag under direct mode.  

Cc: Paolo Bonzini 
Cc: Radim Krčmář 
Cc: Brijesh Singh 
Signed-off-by: Wanpeng Li 
---
 arch/x86/kvm/mmu.c | 6 --
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 849312d..a038879 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3791,8 +3791,10 @@ int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 
error_code,
 
if (need_unprotect && kvm_event_needs_reinjection(vcpu))
kvm_mmu_unprotect_page_virt(vcpu, fault_address);
-   vcpu->arch.gpa_available = true;
-   vcpu->arch.gpa_val = fault_address;
+   if (vcpu->arch.mmu.direct_map) {
+   vcpu->arch.gpa_available = true;
+   vcpu->arch.gpa_val = fault_address;
+   }
r = kvm_mmu_page_fault(vcpu, fault_address, error_code, insn,
insn_len);
break;
-- 
2.7.4

[PATCH v2] KVM: MMU: Fix guest stuck during boot due to read/write emulation against GVA

[Wanpeng Li]

From: Wanpeng Li 

Commit c016004494b0 (KVM: x86: Avoid guest page table walk when gpa_available 
is set) avoids the page table walk when cr2 has already contained a valid GPA. 
However, that is not the truth if ept == 0 and shadow page table is used. In 
this scenario cr2 can just contains a valid GVA. The commit results in guest 
stuck during boot due to read/write emulation against GVA instead of GPA of 
the guest.

This patch fixes it by setting the gpa_available flag under direct mode.  

Cc: Paolo Bonzini 
Cc: Radim Krčmář 
Cc: Brijesh Singh 
Signed-off-by: Wanpeng Li 
---
 arch/x86/kvm/mmu.c | 6 --
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 849312d..a038879 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3791,8 +3791,10 @@ int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 
error_code,
 
if (need_unprotect && kvm_event_needs_reinjection(vcpu))
kvm_mmu_unprotect_page_virt(vcpu, fault_address);
-   vcpu->arch.gpa_available = true;
-   vcpu->arch.gpa_val = fault_address;
+   if (vcpu->arch.mmu.direct_map) {
+   vcpu->arch.gpa_available = true;
+   vcpu->arch.gpa_val = fault_address;
+   }
r = kvm_mmu_page_fault(vcpu, fault_address, error_code, insn,
insn_len);
break;
-- 
2.7.4