From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eduardo Habkost Subject: Re: [PULL 4/4] i386: Add "stibp" flag name Date: Wed, 12 Dec 2018 15:11:51 -0200 Message-ID: <20181212171151.GW7141@habkost.net> References: <20181211205346.11118-1-ehabkost@redhat.com> <20181211205346.11118-5-ehabkost@redhat.com> <20181212170110.GJ31033@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Cc: "Lendacky, Thomas" , "kvm@vger.kernel.org" , "Michael S. Tsirkin" , Peter Maydell , Marcelo Tosatti , "qemu-devel@nongnu.org" , Paolo Bonzini , Richard Henderson To: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= Return-path: Content-Disposition: inline In-Reply-To: <20181212170110.GJ31033@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel2=m.gmane.org@nongnu.org Sender: "Qemu-devel" List-Id: kvm.vger.kernel.org On Wed, Dec 12, 2018 at 05:01:10PM +0000, Daniel P. Berrang=E9 wrote: > On Wed, Dec 12, 2018 at 04:57:42PM +0000, Lendacky, Thomas wrote: > > On 12/11/2018 02:53 PM, Eduardo Habkost wrote: > > > The STIBP flag may be supported by the host KVM module, so QEMU > > > can allow it to be configured manually, and it can be exposed to > > > guests when using "-cpu host". > > >=20 > > > No additional migration code is required because the whole > > > contents of spec_ctrl is already migrated in the "cpu/spec_ctrl" > > > section. > > >=20 > > > Corresponding KVM patch was submitted at: > > > https://lore.kernel.org/lkml/20181205191956.31480-1-ehabkost@redhat= .com/ > > >=20 > > > Signed-off-by: Eduardo Habkost > > > Message-Id: <20181210180250.31299-1-ehabkost@redhat.com> > > > Signed-off-by: Eduardo Habkost > > > --- > > > target/i386/cpu.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > >=20 > > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > > > index 86a934d450..12f559b6af 100644 > > > --- a/target/i386/cpu.c > > > +++ b/target/i386/cpu.c > > > @@ -1042,7 +1042,7 @@ static FeatureWordInfo feature_word_info[FEAT= URE_WORDS] =3D { > > > NULL, NULL, NULL, NULL, > > > NULL, NULL, "pconfig", NULL, > > > NULL, NULL, NULL, NULL, > > > - NULL, NULL, "spec-ctrl", NULL, > > > + NULL, NULL, "spec-ctrl", "stibp", > >=20 > > I guess I missed this earlier. Is there a corresponding patch for the= AMD > > STIBP bit (CPUID 0x80000008_EBX[15]) that is in KVM? >=20 > This Intel STIBP patch is one that many distros have carried downstream > since the flaw came to light. >=20 > I've not seen any equiv patch for AMD STIBP bit, in either QMEU or libv= irt, > so guess that's a gap that needs filling. I can submit a "amd-stibp" patch for completeness, although I doubt many people will actually use the flag. --=20 Eduardo