| From | Ben Hutchings <> | Date | Wed, 20 May 2020 15:14:45 +0100 | Subject | [PATCH 3.16 77/99] KVM: x86: Refactor picdev_write() to prevent Spectre-v1/L1TF attacks |
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3.16.84-rc1 review patch. If anyone has any objections, please let me know.
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From: Marios Pomonis <pomonis@google.com>
commit 14e32321f3606e4b0970200b6e5e47ee6f1e6410 upstream.
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: 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> Reviewed-by: Jim Mattson <jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [bwh: Backported to 3.16: pic_{,un}lock() are called outside the switch] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- --- a/arch/x86/kvm/i8259.c +++ b/arch/x86/kvm/i8259.c @@ -486,9 +486,11 @@ static int picdev_write(struct kvm_pic * switch (addr) { case 0x20: case 0x21: + pic_ioport_write(&s->pics[0], addr, data); + break; case 0xa0: case 0xa1: - pic_ioport_write(&s->pics[addr >> 7], addr, data); + pic_ioport_write(&s->pics[1], addr, data); break; case 0x4d0: case 0x4d1:
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