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    Subject[PATCH v2 03/13] KVM: x86: Refactor picdev_write() to prevent Spectre-v1/L1TF attacks
    From
    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:
    --
    2.24.0.525.g8f36a354ae-goog
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