From 656ec4a4928a3db7d16e5cb9bce351a478cfd3d5 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@redhat.com>
Date: Mon, 2 Nov 2015 22:20:00 +0100
Subject: [PATCH] KVM: VMX: fix SMEP and SMAP without EPT
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit
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 KrÄmáŠ<rkrcmar@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/vmx.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 4d0aa31a42baa..2ac1164175837 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;
--
2.30.2