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bh=Ig2mq+AH5o0UP+b5KHhG9X0qqULQtiCnJDgxb4T5GVk=; b=WYV04JuNDWrRuUr6KRpyB7wIUxY8n1yb/5eqvsXy8BTTJUdpr842g6NxvuFSmuufQN u71YQRuZtH2lH4V1H/A5dcdzfYCnfo03nBBntPuoeSWll7M4ZA01ogwK06Zs5+QnXcaL g1GRt15qI1XKRP5mc+QZjgHm4g7+1JbCju4QXz2/Iuc9B3ixYsCukOfW2KzpP/y814UX ft6T4KFP6hFsQ1U0T/4EJqeTCkDLnRAUnWfrvFjAUWW8ldb6tCgQe6JuNTR8ThyFvA0F U/E5w3zphSSOi4McJSio4uNUy+SR7QWs0I37c09NngUKIC81UH3ekAR5PP3WGpU1UOd+ rpuA== X-Gm-Message-State: AGi0PuY2+92Pm5mgRkV9+1pPz/b62G4BHYHDFlvXrqem6AxHLmEvB2cG QMLj02rbgHfz+8S3tOgPhQdjeM1UnIN10YAECDImAQ== X-Google-Smtp-Source: APiQypLPwRgW4x4+sMjDp/TWI4NTo7d5tYyS36ZSVaDFbxEF/D5s3AnWWgYm2v2l2t9PPVUgnprj5uycuII70QtXf4Q= X-Received: by 2002:a92:3a8c:: with SMTP id i12mr1977302ilf.69.1586259159061; Tue, 07 Apr 2020 04:32:39 -0700 (PDT) MIME-Version: 1.0 References: <20200323113227.3169-1-beata.michalska@linaro.org> <20200323113227.3169-3-beata.michalska@linaro.org> <20200403084435.zvfewiivn7orsnll@kamzik.brq.redhat.com> In-Reply-To: From: Beata Michalska Date: Tue, 7 Apr 2020 12:32:28 +0100 Message-ID: Subject: Re: [PATCH v4 2/2] target/arm: kvm: Handle potential issue with dabt injection To: Peter Maydell Cc: QEMU Developers , qemu-arm , Paolo Bonzini , kvmarm@lists.cs.columbia.edu X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============7080173194101324153==" Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu --===============7080173194101324153== Content-Type: multipart/alternative; boundary="000000000000b2abce05a2b1bd16" --000000000000b2abce05a2b1bd16 Content-Type: text/plain; charset="UTF-8" On Tue, 7 Apr 2020 at 12:24, Peter Maydell wrote: > > On Fri, 3 Apr 2020 at 09:44, Andrew Jones wrote: > > > > On Mon, Mar 23, 2020 at 11:32:27AM +0000, Beata Michalska wrote: > > > Injecting external data abort through KVM might trigger > > > an issue on kernels that do not get updated to include the KVM fix. > > > For those and aarch32 guests, the injected abort gets misconfigured > > > to be an implementation defined exception. This leads to the guest > > > repeatedly re-running the faulting instruction. > > > > > > Add support for handling that case. > > > [ > > > Fixed-by: 018f22f95e8a > > > ('KVM: arm: Fix DFSR setting for non-LPAE aarch32 guests') > > > Fixed-by: 21aecdbd7f3a > > > ('KVM: arm: Make inject_abt32() inject an external abort instead') > > > ] > > > > > > I'll leave the decision to take this KVM bug workaround patch at all to Peter, > > and I didn't actually review whether or not kvm_arm_verify_ext_dabt_pending > > is doing what it claims it's doing, so I'm reluctant to give an r-b on > > this patch. But, as far as the code goes, besides the comments above, it > > looks fine to me. > > I think that having the workaround for the broken kernels is > reasonable (in fact it might have been my suggestion). > I will update the current version to cover the review feedback and resend the patches soon. Thanks a lot! BR Beata > thanks > -- PMM --000000000000b2abce05a2b1bd16 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On Tue, 7 Apr 2020 at 12:24, Peter Maydell <peter.maydell@linaro.org> wrote: >
> On Fri, 3 Apr 2020 at 09:44, Andrew Jones <drjones@redhat.com> wrote:
> >
> > On Mon, Mar 23, 2020 at 11:32:27AM +0000, Beata Michalska wrote:<= br> > > > Injecting external data abort through KVM might trigger
> > > an issue on kernels that do not get updated to include the K= VM fix.
> > > For those and aarch32 guests, the injected abort gets miscon= figured
> > > to be an implementation defined exception. This leads to the= guest
> > > repeatedly re-running the faulting instruction.
> > >
> > > Add support for handling that case.
> > > [
> > >=C2=A0 =C2=A0Fixed-by: 018f22f95e8a
> > >=C2=A0 =C2=A0 =C2=A0 =C2=A0('KVM: arm: Fix DFSR setting f= or non-LPAE aarch32 guests')
> > >=C2=A0 =C2=A0Fixed-by: 21aecdbd7f3a
> > >=C2=A0 =C2=A0 =C2=A0 =C2=A0('KVM: arm: Make inject_abt32(= ) inject an external abort instead')
> > > ]
> > >
>
> > I'll leave the decision to take this KVM bug workaround patch= at all to Peter,
> > and I didn't actually review whether or not kvm_arm_verify_ex= t_dabt_pending
> > is doing what it claims it's doing, so I'm reluctant to g= ive an r-b on
> > this patch. But, as far as the code goes, besides the comments ab= ove, it
> > looks fine to me.
>
> I think that having the workaround for the broken kernels is
> reasonable (in fact it might have been my suggestion).
>

I will update the current version to cover the review feedback
and resend the patches soon.

Thanks a lot!

BR
Beata
> thanks
> -- PMM
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