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

commit c4409905cd 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: d391f12070 ("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>
pull/10/head
Sean Christopherson 2018-08-23 13:56:46 -07:00 committed by Greg Kroah-Hartman
parent d5fca5314c
commit a709c46fdc
1 changed files with 2 additions and 2 deletions
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4
arch/x86/kvm/vmx.c
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@ -6965,8 +6965,8 @@ 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;
}
ret = kvm_mmu_page_fault(vcpu, gpa, PFERR_RSVD_MASK, NULL, 0);