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KVM: Disable SMAP for guests in EPT realmode and EPT unpaging mode

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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.wu@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Feng Wu 2014-04-01 17:46:35 +08:00 committed by Marcelo Tosatti
parent 97ec8c067d
commit e1e746b3c5
1 changed files with 6 additions and 5 deletions
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11
arch/x86/kvm/vmx.c
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@ -3484,13 +3484,14 @@ static int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
hw_cr4 &= ~X86_CR4_PAE; hw_cr4 &= ~X86_CR4_PAE;
hw_cr4 |= X86_CR4_PSE; hw_cr4 |= X86_CR4_PSE;
/* /*
* SMEP is disabled if CPU is in non-paging mode in * SMEP/SMAP is disabled if CPU is in non-paging mode
* hardware. However KVM always uses paging mode to * in hardware. However KVM always uses paging mode to
* emulate guest non-paging mode with TDP. * emulate guest non-paging mode with TDP.
* To emulate this behavior, SMEP needs to be manually * To emulate this behavior, SMEP/SMAP needs to be
* disabled when guest switches to non-paging mode. * manually disabled when guest switches to non-paging
* mode.
*/ */
hw_cr4 &= ~X86_CR4_SMEP; hw_cr4 &= ~(X86_CR4_SMEP | X86_CR4_SMAP);
} else if (!(cr4 & X86_CR4_PAE)) { } else if (!(cr4 & X86_CR4_PAE)) {
hw_cr4 &= ~X86_CR4_PAE; hw_cr4 &= ~X86_CR4_PAE;
} }