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 4.9-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-4.9 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 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 @@ -3071,6 +3071,9 @@ static int vmx_set_msr(struct kvm_vcpu * case MSR_IA32_BNDCFGS: if (!kvm_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-4.9/kvm-x86-guest-bndcfgs-requires-guest-mpx-support.patch queue-4.9/kvm-vmx-check-value-written-to-ia32_bndcfgs.patch queue-4.9/kvm-vmx-do-not-disable-intercepts-for-bndcfgs.patch