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Subject[PATCH] KVM: MMU: Fix guest stuck during boot due to read/write emulation against GVA
Date
From: Wanpeng Li <wanpeng.li@hotmail.com>

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 not setting the gpa_available flag if the shadow page table
is used.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
---
arch/x86/kvm/mmu.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 849312d..e4ce20b 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3791,8 +3791,6 @@ 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;
r = kvm_mmu_page_fault(vcpu, fault_address, error_code, insn,
insn_len);
break;
--
2.7.4
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