KVM: nVMX: Trap unconditionally if msr bitmap access fails
This avoids basing decisions on uninitialized variables, potentially
leaking kernel data to the L1 guest.
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index b4ce43c..c1b3041 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5985,7 +5985,8 @@
/* Then read the msr_index'th bit from this bitmap: */
if (msr_index < 1024*8) {
unsigned char b;
- kvm_read_guest(vcpu->kvm, bitmap + msr_index/8, &b, 1);
+ if (kvm_read_guest(vcpu->kvm, bitmap + msr_index/8, &b, 1))
+ return 1;
return 1 & (b >> (msr_index & 7));
} else
return 1; /* let L1 handle the wrong parameter */