lkml.org 
[lkml]   [2020]   [Apr]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.9 050/102] KVM: VMX: Do not allow reexecute_instruction() when skipping MMIO instr
Date
From: Sean Christopherson <sean.j.christopherson@intel.com>

[ 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>
---
arch/x86/kvm/vmx.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 8bd336651de52..1fa4545c55e35 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6564,8 +6564,8 @@ 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 = kvm_mmu_page_fault(vcpu, gpa, PFERR_RSVD_MASK, NULL, 0);
--
2.20.1


\
 
 \ /
  Last update: 2020-04-01 18:37    [W:0.318 / U:1.212 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site