From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH 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 Message-ID: <20190131071820.GC4500@kroah.com> References: <20190130220731.92849-1-dverkamp@chromium.org> <20190130222926.120454-1-dverkamp@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: stable@vger.kernel.org, Rik van Riel , kvm@vger.kernel.org To: Daniel Verkamp Return-path: Content-Disposition: inline In-Reply-To: <20190130222926.120454-1-dverkamp@chromium.org> Sender: stable-owner@vger.kernel.org List-Id: kvm.vger.kernel.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 > --- > > 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