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authorRadim Krčmář <rkrcmar@redhat.com>2015-11-02 22:20:00 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2015-11-04 16:24:37 +0100
commit656ec4a4928a3db7d16e5cb9bce351a478cfd3d5 (patch)
tree2eadec89b6429d14d08171e99b0ba8e684e8d054 /arch
parent8a22f234a81ab4d1de5d948c3478608f08a9b844 (diff)
downloadlinux-656ec4a4928a3db7d16e5cb9bce351a478cfd3d5.tar.bz2
KVM: VMX: fix SMEP and SMAP without EPT
The comment in code had it mostly right, but we enable paging for emulated real mode regardless of EPT. Without EPT (which implies emulated real mode), secondary VCPUs won't start unless we disable SM[AE]P when the guest doesn't use paging. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/vmx.c19
1 files changed, 10 insertions, 9 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 4d0aa31a42ba..2ac116417583 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3788,20 +3788,21 @@ static int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
if (!is_paging(vcpu)) {
hw_cr4 &= ~X86_CR4_PAE;
hw_cr4 |= X86_CR4_PSE;
- /*
- * 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/SMAP needs to be
- * manually disabled when guest switches to non-paging
- * mode.
- */
- hw_cr4 &= ~(X86_CR4_SMEP | X86_CR4_SMAP);
} else if (!(cr4 & X86_CR4_PAE)) {
hw_cr4 &= ~X86_CR4_PAE;
}
}
+ if (!enable_unrestricted_guest && !is_paging(vcpu))
+ /*
+ * SMEP/SMAP is disabled if CPU is in non-paging mode in
+ * hardware. However KVM always uses paging mode without
+ * unrestricted guest.
+ * To emulate this behavior, SMEP/SMAP needs to be manually
+ * disabled when guest switches to non-paging mode.
+ */
+ hw_cr4 &= ~(X86_CR4_SMEP | X86_CR4_SMAP);
+
vmcs_writel(CR4_READ_SHADOW, cr4);
vmcs_writel(GUEST_CR4, hw_cr4);
return 0;