-Original Message-
From: kvm-ow...@vger.kernel.org [mailto:kvm-ow...@vger.kernel.org] On
Behalf Of Jan Kiszka
Sent: Friday, March 28, 2014 12:15 AM
To: Wu, Feng; pbonz...@redhat.com; g...@redhat.com; h...@zytor.com;
kvm@vger.kernel.org
Subject: Re: [PATCH 4/4] KVM: Disable SMAP for guests in EPT realmode and
EPT unpaging mode
On 2014-03-27 13:25, Feng Wu wrote:
SMAP is disabled if CPU is in non-paging mode in hardware.
However KVM always uses paging mode to emulate guest non-paging
mode with TDP. To emulate this behavior, SMAP needs to be
manually disabled when guest switches to non-paging mode.
Signed-off-by: Feng Wu feng...@intel.com
---
arch/x86/kvm/vmx.c | 10 ++
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index dcc4de3..1d37e50 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3421,13 +3421,15 @@ static int vmx_set_cr4(struct kvm_vcpu *vcpu,
unsigned long cr4)
hw_cr4 = ~X86_CR4_PAE;
hw_cr4 |= X86_CR4_PSE;
/*
-* SMEP is disabled if CPU is in non-paging mode in
-* hardware. However KVM always uses paging mode to
+* SMEP/SMAP is disabled if CPU is in non-paging mode
+* in hardware. However KVM always uses paging mode to
* emulate guest non-paging mode with TDP.
-* To emulate this behavior, SMEP needs to be manually
-* disabled when guest switches to non-paging mode.
+* To emulate this behavior, SMEP/SMAP needs to be
+* manually disabled when guest switches to non-paging
+* mode.
*/
hw_cr4 = ~X86_CR4_SMEP;
+ hw_cr4 = ~X86_CR4_SMAP;
Why not
hw_cr4 = ~(X86_CR4_SMEP | X86_CR4_SMAP);
?
Sure, your suggestion is cleaner, I will change it in the next version, thanks
for the comments!
Jan
} else if (!(cr4 X86_CR4_PAE)) {
hw_cr4 = ~X86_CR4_PAE;
}
Thanks,
Feng
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