[v2,1/8] KVM: VMX: Do not allow reexecute_instruction() when skipping MMIO instr
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Message ID 20180823205653.3264-2-sean.j.christopherson@intel.com
State New
Headers show
Series
  • KVM: x86: Fix the emulation type mess
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Commit Message

Sean Christopherson Aug. 23, 2018, 8:56 p.m. UTC
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>
---
 arch/x86/kvm/vmx.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Patch
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diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 8dae47e7267a..efb5721a6c46 100644
--- 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);