Patch "kvm: vmx: Do not disable intercepts for BNDCFGS" has been added to the 4.12-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    kvm: vmx: Do not disable intercepts for BNDCFGS

to the 4.12-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-do-not-disable-intercepts-for-bndcfgs.patch
and it can be found in the queue-4.12 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 a8b6fda38f80e75afa3b125c9e7f2550b579454b Mon Sep 17 00:00:00 2001
From: Jim Mattson <jmattson@google.com>
Date: Tue, 23 May 2017 11:52:52 -0700
Subject: kvm: vmx: Do not disable intercepts for BNDCFGS
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From: Jim Mattson <jmattson@google.com>

commit a8b6fda38f80e75afa3b125c9e7f2550b579454b upstream.

The MSR permission bitmaps are shared by all VMs. However, some VMs
may not be configured to support MPX, even when the host does. If the
host supports VMX and the guest does not, we should intercept accesses
to the BNDCFGS MSR, so that we can synthesize a #GP
fault. Furthermore, if the host does not support MPX and the
"ignore_msrs" kvm kernel parameter is set, then we should intercept
accesses to the BNDCFGS MSR, so that we can skip over the rdmsr/wrmsr
without raising a #GP fault.

Fixes: da8999d31818fdc8 ("KVM: x86: Intel MPX vmx and msr handle")
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/kvm/vmx.c |    1 -
 1 file changed, 1 deletion(-)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6547,7 +6547,6 @@ static __init int hardware_setup(void)
 	vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_CS, false);
 	vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_ESP, false);
 	vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP, false);
-	vmx_disable_intercept_for_msr(MSR_IA32_BNDCFGS, true);
 
 	memcpy(vmx_msr_bitmap_legacy_x2apic_apicv,
 			vmx_msr_bitmap_legacy, PAGE_SIZE);


Patches currently in stable-queue which might be from jmattson@google.com are

queue-4.12/kvm-x86-guest-bndcfgs-requires-guest-mpx-support.patch
queue-4.12/kvm-vmx-check-value-written-to-ia32_bndcfgs.patch
queue-4.12/kvm-vmx-do-not-disable-intercepts-for-bndcfgs.patch