KVM: VMX: Do not allow reexecute_instruction() when skipping MMIO instr

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>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 92f027745842c8abfe7655cc51b8d337a3afd640..b345ad91809c0bf138b6b61b9a52aa15a849bc15 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7704,8 +7704,8 @@ static int handle_ept_misconfig(struct kvm_vcpu *vcpu)
                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;
        }
 
        return kvm_mmu_page_fault(vcpu, gpa, PFERR_RSVD_MASK, NULL, 0);