| From c4409905cd6eb42cfd06126e9226b0150e05a715 Mon Sep 17 00:00:00 2001 |
| From: Sean Christopherson <sean.j.christopherson@intel.com> |
| Date: Thu, 23 Aug 2018 13:56:46 -0700 |
| Subject: KVM: VMX: Do not allow reexecute_instruction() when skipping MMIO instr |
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| |
| From: Sean Christopherson <sean.j.christopherson@intel.com> |
| |
| commit c4409905cd6eb42cfd06126e9226b0150e05a715 upstream. |
| |
| Re-execution after an emulation decode failure is only intended to |
| handle a case where two or vCPUs race to write a shadowed page, i.e. |
| we should never re-execute an instruction as part of MMIO emulation. |
| As handle_ept_misconfig() is only used for MMIO emulation, it should |
| pass EMULTYPE_NO_REEXECUTE when using the emulator to skip an instr |
| in the fast-MMIO case where VM_EXIT_INSTRUCTION_LEN is invalid. |
| |
| And because the cr2 value passed to x86_emulate_instruction() is only |
| destined for use when retrying or reexecuting, we can simply call |
| emulate_instruction(). |
| |
| Fixes: d391f1207067 ("x86/kvm/vmx: do not use vm-exit instruction length |
| for fast MMIO when running nested") |
| Cc: Vitaly Kuznetsov <vkuznets@redhat.com> |
| Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> |
| Cc: stable@vger.kernel.org |
| Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/x86/kvm/vmx.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/arch/x86/kvm/vmx.c |
| +++ b/arch/x86/kvm/vmx.c |
| @@ -6965,8 +6965,8 @@ static int handle_ept_misconfig(struct k |
| if (!static_cpu_has(X86_FEATURE_HYPERVISOR)) |
| return kvm_skip_emulated_instruction(vcpu); |
| else |
| - return x86_emulate_instruction(vcpu, gpa, EMULTYPE_SKIP, |
| - NULL, 0) == EMULATE_DONE; |
| + return emulate_instruction(vcpu, EMULTYPE_SKIP) == |
| + EMULATE_DONE; |
| } |
| |
| ret = kvm_mmu_page_fault(vcpu, gpa, PFERR_RSVD_MASK, NULL, 0); |
