@@ -3523,20 +3523,21 @@ 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;
This is a note to let you know that I have just added a patch titled KVM: VMX: fix SMEP and SMAP without EPT to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt21. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 8dd148bc3504dff83ea221fb55425d79cc6d3c7b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@redhat.com> Date: Mon, 2 Nov 2015 22:20:00 +0100 Subject: KVM: VMX: fix SMEP and SMAP without EPT MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 656ec4a4928a3db7d16e5cb9bce351a478cfd3d5 upstream. 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> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- arch/x86/kvm/vmx.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-)