kvm: vmx: Check value written to IA32_BNDCFGS

BugLink: http://bugs.launchpad.net/bugs/1705707
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>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 10be84b735f31c6543204de521a113ac166659ec..9d1b4bc6ae601ae4550f1a1c721fb0ab1c6cb075 100644 (file)
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -413,6 +413,8 @@
 #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)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c6442e1cd633a5d796d5d3c52bcc7c03a4bc0235..004b387d1c16055b8a111d981250ad365d3936fc 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2892,6 +2892,9 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
        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: