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@google.com Signed-off-by: Marios Pomonis pomonis@google.com Reviewed-by: Andrew Honig ahonig@google.com Cc: stable@vger.kernel.org --- 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: