From: Marios Pomonis <pomonis@xxxxxxxxxx>
commit ea740059ecb37807ba47b84b33d1447435a8d868 upstream.
This fixes a Spectre-v1/L1TF vulnerability in __kvm_set_dr() and
kvm_get_dr().
Both kvm_get_dr() and kvm_set_dr() (a wrapper of __kvm_set_dr()) are
exported symbols so KVM should tream them conservatively from a security
perspective.
Fixes: 020df0794f57 ("KVM: move DR register access handling into generic code")
Signed-off-by: Nick Finco <nifi@xxxxxxxxxx>
Signed-off-by: Marios Pomonis <pomonis@xxxxxxxxxx>
Reviewed-by: Andrew Honig <ahonig@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -53,6 +53,7 @@
#include <linux/pvclock_gtod.h>
#include <linux/kvm_irqfd.h>
#include <linux/irqbypass.h>
+#include <linux/nospec.h>
#include <trace/events/kvm.h>
#define CREATE_TRACE_POINTS
@@ -873,9 +874,11 @@ static u64 kvm_dr6_fixed(struct kvm_vcpu
static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
{
+ size_t size = ARRAY_SIZE(vcpu->arch.db);
+
switch (dr) {
case 0 ... 3:
- vcpu->arch.db[dr] = val;
+ vcpu->arch.db[array_index_nospec(dr, size)] = val;
if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
vcpu->arch.eff_db[dr] = val;
break;
@@ -912,9 +915,11 @@ EXPORT_SYMBOL_GPL(kvm_set_dr);
int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val)
{
+ size_t size = ARRAY_SIZE(vcpu->arch.db);
+
switch (dr) {
case 0 ... 3:
- *val = vcpu->arch.db[dr];
+ *val = vcpu->arch.db[array_index_nospec(dr, size)];
break;
case 4:
/* fall through */
