This is a note to let you know that I've just added the patch titled
kvm: vmx: Check value written to IA32_BNDCFGS
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-vmx-check-value-written-to-ia32_bndcfgs.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4531662d1abf6c1f0e5c2b86ddb60e61509786c8 Mon Sep 17 00:00:00 2001
From: Jim Mattson <jmattson@xxxxxxxxxx>
Date: Tue, 23 May 2017 11:52:54 -0700
Subject: kvm: vmx: Check value written to IA32_BNDCFGS
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From: Jim Mattson <jmattson@xxxxxxxxxx>
commit 4531662d1abf6c1f0e5c2b86ddb60e61509786c8 upstream.
Bits 11:2 must be zero and the linear addess in bits 63:12 must be
canonical. Otherwise, WRMSR(BNDCFGS) should raise #GP.
Fixes: 0dd376e709975779 ("KVM: x86: add MSR_IA32_BNDCFGS to msrs_to_save")
Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/msr-index.h | 2 ++
arch/x86/kvm/vmx.c | 3 +++
2 files changed, 5 insertions(+)
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -405,6 +405,8 @@
#define MSR_IA32_TSC_ADJUST 0x0000003b
#define MSR_IA32_BNDCFGS 0x00000d90
+#define MSR_IA32_BNDCFGS_RSVD 0x00000ffc
+
#define MSR_IA32_XSS 0x00000da0
#define FEATURE_CONTROL_LOCKED (1<<0)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2892,6 +2892,9 @@ static int vmx_set_msr(struct kvm_vcpu *
case MSR_IA32_BNDCFGS:
if (!vmx_mpx_supported() || !guest_cpuid_has_mpx(vcpu))
return 1;
+ if (is_noncanonical_address(data & PAGE_MASK) ||
+ (data & MSR_IA32_BNDCFGS_RSVD))
+ return 1;
vmcs_write64(GUEST_BNDCFGS, data);
break;
case MSR_IA32_TSC:
Patches currently in stable-queue which might be from jmattson@xxxxxxxxxx are
queue-4.4/kvm-x86-guest-bndcfgs-requires-guest-mpx-support.patch
queue-4.4/kvm-vmx-check-value-written-to-ia32_bndcfgs.patch
queue-4.4/kvm-vmx-do-not-disable-intercepts-for-bndcfgs.patch