From: Eugene Korenevsky <ekorenevsky@gmail.com>
To: kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Subject: [PATCH 5/5] KVM: nVMX: VMWRITE emulation: remove unnecessary check for compatibility mode
Date: Thu, 20 Aug 2015 22:38:20 +0300 [thread overview]
Message-ID: <20150820193820.GA3593@unote> (raw)
VMWRITE instruction is not valid in compatibility mode. This is
checked by nested_vmx_check_permission() function which throws #UD if CS.L=0.
The additional check in is_64_bit_mode() for CS.L=0 is useless.
We should check only EFER.LMA=1 which is done by is_long_mode().
Signed-off-by: Eugene Korenevsky <ekorenevsky@gmail.com>
---
arch/x86/kvm/vmx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f39e24f..12bdaae 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7034,7 +7034,7 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu)
field_value = kvm_register_readl(vcpu,
(((vmx_instruction_info) >> 3) & 0xf));
else {
- mem_op_size = is_64_bit_mode(vcpu) ? 8 : 4;
+ mem_op_size = is_long_mode(vcpu) ? 8 : 4;
if (get_vmx_mem_address(vcpu, exit_qualification,
vmx_instruction_info, false, mem_op_size, &gva))
return 1;
--
2.1.4
next reply other threads:[~2015-08-20 19:38 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-20 19:38 Eugene Korenevsky [this message]
2015-09-07 11:43 ` [PATCH 5/5] KVM: nVMX: VMWRITE emulation: remove unnecessary check for compatibility mode Paolo Bonzini
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