This fixes a Spectre-v1/L1TF vulnerability in picdev_write().
It replaces index computations based on the (attacked-controlled) port
number with constants through a minor refactoring.
Fixes: commit 85f455f7ddbe ("KVM: Add support for in-kernel PIC emulation")
Signed-off-by: Nick Finco <nifi@xxxxxxxxxx>
Signed-off-by: Marios Pomonis <pomonis@xxxxxxxxxx>
Reviewed-by: Andrew Honig <ahonig@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
arch/x86/kvm/i8259.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
index 8b38bb4868a6..629a09ca9860 100644
--- a/arch/x86/kvm/i8259.c
+++ b/arch/x86/kvm/i8259.c
@@ -460,10 +460,14 @@ static int picdev_write(struct kvm_pic *s,
switch (addr) {
case 0x20:
case 0x21:
+ pic_lock(s);
+ pic_ioport_write(&s->pics[0], addr, data);
+ pic_unlock(s);
+ break;
case 0xa0:
case 0xa1:
pic_lock(s);
- pic_ioport_write(&s->pics[addr >> 7], addr, data);
+ pic_ioport_write(&s->pics[1], addr, data);
pic_unlock(s);
break;
case 0x4d0:
--
2.24.0.525.g8f36a354ae-goog
