FAILED: patch "[PATCH] KVM: x86: Refactor picdev_write() to prevent Spectre-v1/L1TF" failed to apply to 4.4-stable tree

FAILED: patch "[PATCH] KVM: x86: Refactor picdev_write() to prevent Spectre-v1/L1TF" failed to apply to 4.4-stable tree

[gregkh]

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 14e32321f3606e4b0970200b6e5e47ee6f1e6410 Mon Sep 17 00:00:00 2001
From: Marios Pomonis <pomonis@google.com>
Date: Wed, 11 Dec 2019 12:47:43 -0800
Subject: [PATCH] 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: 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
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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:

Re: FAILED: patch "[PATCH] KVM: x86: Refactor picdev_write() to prevent Spectre-v1/L1TF" failed to apply to 4.4-stable tree

[Sasha Levin]

On Sun, Feb 09, 2020 at 12:54:21PM +0100, gregkh@linuxfoundation.org wrote:
>
>The patch below does not apply to the 4.4-stable tree.
>If someone wants it applied there, or to any other stable or longterm
>tree, then please email the backport, including the original git commit
>id to <stable@vger.kernel.org>.
>
>thanks,
>
>greg k-h
>
>------------------ original commit in Linus's tree ------------------
>
>From 14e32321f3606e4b0970200b6e5e47ee6f1e6410 Mon Sep 17 00:00:00 2001
>From: Marios Pomonis <pomonis@google.com>
>Date: Wed, 11 Dec 2019 12:47:43 -0800
>Subject: [PATCH] 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: 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
>Reviewed-by: Jim Mattson <jmattson@google.com>
>Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

I took in 9fecaa9e32ae ("KVM: x86: drop picdev_in_range()") as a
dependency and queued both for 4.4.

-- 
Thanks,
Sasha