From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Jim Mattson <jmattson@google.com>
Cc: kvm@vger.kernel.org, P J P <ppandit@redhat.com>,
Andrew Honig <ahonig@google.com>
Subject: Re: [PATCH 1/2] KVM: VMX: remove I/O port 0x80 bypass on Intel hosts
Date: Tue, 5 Dec 2017 22:32:07 +0100 [thread overview]
Message-ID: <20171205213206.GE20099@flask> (raw)
In-Reply-To: <20171201182110.7143-1-jmattson@google.com>
2017-12-01 10:21-0800, Jim Mattson:
> From: Andrew Honig <ahonig@google.com>
>
> This fixes CVE-2017-1000407.
>
> KVM allows guests to directly access I/O port 0x80 on Intel hosts. If
> the guest floods this port with writes it generates exceptions and
> instability in the host kernel, leading to a crash. With this change
> guest writes to port 0x80 on Intel will behave the same as they
> currently behave on AMD systems.
>
> Prevent the flooding by removing the code that sets port 0x80 as a
> passthrough port. This is essentially the same as upstream patch
> 99f85a28a78e96d28907fe036e1671a218fee597, except that patch was
> for AMD chipsets and this patch is for Intel.
>
> Signed-off-by: Andrew Honig <ahonig@google.com>
> Signed-off-by: Jim Mattson <jmattson@google.com>
Fixes: fdef3ad1b386 ("KVM: VMX: Enable io bitmaps to avoid IO port 0x80 VMEXITs")
Cc: <stable@vger.kernel.org>
Applied, thanks. The commit that introduced it boasted 3-5% performance
improvements when compiling the kernel -- have you noticed regressions?
next prev parent reply other threads:[~2017-12-05 21:32 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-01 18:21 [PATCH 1/2] KVM: VMX: remove I/O port 0x80 bypass on Intel hosts Jim Mattson
2017-12-01 18:21 ` [PATCH 2/2] KVM: VMX: Use just one page for I/O permission bitmaps Jim Mattson
2017-12-04 18:30 ` kbuild test robot
2017-12-04 18:34 ` Jim Mattson
2017-12-05 21:26 ` Radim Krčmář
2017-12-06 0:16 ` Jim Mattson
2017-12-06 11:17 ` Quan Xu
2017-12-06 18:19 ` Jim Mattson
2017-12-07 2:33 ` Quan Xu
2017-12-07 17:06 ` Radim Krčmář
2017-12-08 2:04 ` Quan Xu
2017-12-02 0:34 ` [PATCH 1/2] KVM: VMX: remove I/O port 0x80 bypass on Intel hosts Krish Sadhukhan
2017-12-04 12:44 ` Wanpeng Li
2017-12-04 17:10 ` Jim Mattson
2017-12-05 7:19 ` Wanpeng Li
2017-12-05 11:24 ` Quan Xu
2017-12-05 12:15 ` Wanpeng Li
2017-12-05 21:32 ` Radim Krčmář [this message]
2017-12-06 0:36 ` Jim Mattson
2017-12-06 1:38 ` Quan Xu
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