From: Greg KH <gregkh@linuxfoundation.org>
To: Daniel Verkamp <dverkamp@chromium.org>
Cc: stable@vger.kernel.org, Rik van Riel <riel@redhat.com>,
kvm@vger.kernel.org
Subject: Re: [PATCH v2 for-4.14-stable] x86,kvm: remove extra kvm_{get,put}_guest_fpu
Date: Thu, 31 Jan 2019 08:18:20 +0100 [thread overview]
Message-ID: <20190131071820.GC4500@kroah.com> (raw)
In-Reply-To: <20190130222926.120454-1-dverkamp@chromium.org>
On Wed, Jan 30, 2019 at 02:29:26PM -0800, Daniel Verkamp wrote:
> Commit 4124a4cff344 ("x86,kvm: move qemu/guest FPU switching out
> to vcpu_run") applied a patch from upstream, but it appears that it
> wasn't backported correctly to 4.14. The extra out_fpu label and
> kvm_put_guest_fpu() added in kvm_arch_vcpu_ioctl_run() result in calling
> kvm_put_guest_fpu() twice in a row, corrupting guest state.
> Additionally, a duplicate kvm_load_guest_fpu() is added in the middle of
> the function.
>
> Fixes: 4124a4cff344 ("x86,kvm: move qemu/guest FPU switching out to vcpu_run")
> Signed-off-by: Daniel Verkamp <dverkamp@chromium.org>
> ---
>
> v2: removed additional redundant kvm_load_guest_fpu()
>
> I'm unsure if this is the right way to send this fix - there is no
> corresponding mainline commit to reference, since the code there is
> already correct, and the problem was introduced in the cherry-picked
> stable backport. Please let me know if there's a different process for
> fixes to stable-only issues.
This should now be fixed with 9485d5d2318b ("KVM: x86: Fix a 4.14
backport regression related to userspace/guest FPU") in the 4.14.97
release that just happened, right?
thanks,
greg k-h
next prev parent reply other threads:[~2019-01-31 7:18 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-30 22:07 [PATCH] x86,kvm: remove duplicate kvm_put_guest_fpu() Daniel Verkamp
2019-01-30 22:29 ` [PATCH v2 for-4.14-stable] x86,kvm: remove extra kvm_{get,put}_guest_fpu Daniel Verkamp
2019-01-30 22:42 ` Daniel Verkamp
2019-01-31 7:18 ` Greg KH [this message]
2019-01-31 17:14 ` Daniel Verkamp
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