Patch "kvm: vmx: Check value written to IA32_BNDCFGS" has been added to the 4.4-stable tree

Patch "kvm: vmx: Check value written to IA32_BNDCFGS" has been added to the 4.4-stable tree

[gregkh]

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@vger.kernel.org> know about it.


>From 4531662d1abf6c1f0e5c2b86ddb60e61509786c8 Mon Sep 17 00:00:00 2001
From: Jim Mattson <jmattson@google.com>
Date: Tue, 23 May 2017 11:52:54 -0700
Subject: kvm: vmx: Check value written to IA32_BNDCFGS
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Jim Mattson <jmattson@google.com>

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@google.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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@google.com 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