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

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[ Upstream commit c4409905cd6eb42cfd06126e9226b0150e05a715 ]

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: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Sean Christopherson 2018-08-23 13:56:46 -07:00 committed by prashantpaddune
parent 8cd110a2a9
commit c403bdb631
1 changed files with 2 additions and 2 deletions
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4
arch/x86/kvm/vmx.c
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@ -6187,8 +6187,8 @@ static int handle_ept_misconfig(struct kvm_vcpu *vcpu)
return 1;
}
else
return x86_emulate_instruction(vcpu, gpa, EMULTYPE_SKIP,
NULL, 0) == EMULATE_DONE;
return emulate_instruction(vcpu, EMULTYPE_SKIP) ==
EMULATE_DONE;
}
ret = handle_mmio_page_fault(vcpu, gpa, true);