Commit 14e32321 authored by Marios Pomonis's avatar Marios Pomonis Committed by Paolo Bonzini
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KVM: x86: Refactor picdev_write() to prevent Spectre-v1/L1TF attacks 



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: 85f455f7 ("KVM: Add support for in-kernel PIC emulation")

Signed-off-by: default avatarNick Finco <nifi@google.com>
Signed-off-by: default avatarMarios Pomonis <pomonis@google.com>
Reviewed-by: default avatarAndrew Honig <ahonig@google.com>
Cc: stable@vger.kernel.org
Reviewed-by: default avatarJim Mattson <jmattson@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 86187937

arch/x86/kvm/i8259.c

+5 −1
Original line number Diff line number Diff line
@@ -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: