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From:   Jim Mattson <jmattson@google.com>
Date:   Tue, 23 Feb 2021 16:13:54 -0800
Message-ID: <CALMp9eTTBcdADUYizO-ADXUfkydVGqRm0CSQUO92UHNnfQ-qFw@mail.gmail.com>
Subject: Re: [PATCH v6 00/12] SVM cleanup and INVPCID feature support
To:     Babu Moger <babu.moger@amd.com>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        kvm list <kvm@vger.kernel.org>, Joerg Roedel <joro@8bytes.org>,
        "the arch/x86 maintainers" <x86@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H . Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Makarand Sonare <makarandsonare@google.com>,
        Sean Christopherson <seanjc@google.com>
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Any updates? What should we be telling customers with Debian 9 guests? :-)

On Fri, Jan 22, 2021 at 5:52 PM Babu Moger <babu.moger@amd.com> wrote:
>
>
>
> On 1/21/21 5:51 PM, Babu Moger wrote:
> >
> >
> > On 1/20/21 9:10 PM, Babu Moger wrote:
> >>
> >>
> >> On 1/20/21 3:45 PM, Babu Moger wrote:
> >>>
> >>>
> >>> On 1/20/21 3:14 PM, Jim Mattson wrote:
> >>>> On Tue, Jan 19, 2021 at 3:45 PM Babu Moger <babu.moger@amd.com> wrot=
e:
> >>>>>
> >>>>>
> >>>>>
> >>>>> On 1/19/21 5:01 PM, Jim Mattson wrote:
> >>>>>> On Mon, Sep 14, 2020 at 11:33 AM Babu Moger <babu.moger@amd.com> w=
rote:
> >>>>>>
> >>>>>>> Thanks Paolo. Tested Guest/nested guest/kvm units tests. Everythi=
ng works
> >>>>>>> as expected.
> >>>>>>
> >>>>>> Debian 9 does not like this patch set. As a kvm guest, it panics o=
n a
> >>>>>> Milan CPU unless booted with 'nopcid'. Gmail mangles long lines, s=
o
> >>>>>> please see the attached kernel log snippet. Debian 10 is fine, so =
I
> >>>>>> assume this is a guest bug.
> >>>>>>
> >>>>>
> >>>>> We had an issue with PCID feature earlier. This was showing only wi=
th SEV
> >>>>> guests. It is resolved recently. Do you think it is not related tha=
t?
> >>>>> Here are the patch set.
> >>>>> https://nam11.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2=
Flore.kernel.org%2Fkvm%2F160521930597.32054.4906933314022910996.stgit%40bmo=
ger-ubuntu%2F&amp;data=3D04%7C01%7CBabu.Moger%40amd.com%7C3009e5f7f32b4dbd4=
aee08d8bdc045c9%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C63746798084137=
6327%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik=
1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=3D%2Bva7em372XD7uaCrSy3UBH6a9n8xaTTXW=
CAlA3gJX78%3D&amp;reserved=3D0
> >>>>
> >>>> The Debian 9 release we tested is not an SEV guest.
> >>> ok. I have not tested Debian 9 before. I will try now. Will let you k=
now
> >>> how it goes. thanks
> >>>
> >>
> >> I have reproduced the issue locally. Will investigate. thanks
> >>
> > Few updates.
> > 1. Like Jim mentioned earlier, this appears to be guest kernel issue.
> > Debian 9 runs the base kernel 4.9.0-14. Problem can be seen consistentl=
y
> > with this kernel.
> >
> > 2. This guest kernel(4.9.0-14) does not like the new feature INVPCID.
> >
> > 3. System comes up fine when invpcid feature is disabled with the boot
> > parameter "noinvpcid" and also with "nopcid". nopcid disables both pcid
> > and invpcid.
> >
> > 4. Upgraded the guest kernel to v5.0 and system comes up fine.
> >
> > 5. Also system comes up fine with latest guest kernel 5.11.0-rc4.
> >
> > I did not bisect further yet.
> > Babu
> > Thanks
>
>
> Some more update:
>  System comes up fine with kernel v4.9(checked out on upstream tag v4.9).
> So, I am assuming this is something specific to Debian 4.9.0-14 kernel.
>
> Note: I couldn't go back prior versions(v4.8 or earlier) due to compile
> issues.
> Thanks
> Babu
>