From: Borislav Petkov <bp@alien8.de>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Joerg Roedel <joro@8bytes.org>,
x86@kernel.org, kexec@lists.infradead.org,
Joerg Roedel <jroedel@suse.de>,
stable@vger.kernel.org, hpa@zytor.com,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Jiri Slaby <jslaby@suse.cz>,
Dan Williams <dan.j.williams@intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Juergen Gross <jgross@suse.com>,
Kees Cook <keescook@chromium.org>,
David Rientjes <rientjes@google.com>,
Cfir Cohen <cfir@google.com>, Erdem Aktas <erdemaktas@google.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mike Stunes <mstunes@vmware.com>,
Sean Christopherson <seanjc@google.com>,
Martin Radev <martin.b.radev@gmail.com>,
Arvind Sankar <nivedita@alum.mit.edu>,
linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v2 01/12] kexec: Allow architecture code to opt-out at runtime
Date: Tue, 2 Nov 2021 18:17:39 +0100 [thread overview]
Message-ID: <YYFys4KnpTftwJRz@zn.tnic> (raw)
In-Reply-To: <87pmrjbmy9.fsf@disp2133>
On Mon, Nov 01, 2021 at 04:11:42PM -0500, Eric W. Biederman wrote:
> I seem to remember the consensus when this was reviewed that it was
> unnecessary and there is already support for doing something like
> this at a more fine grained level so we don't need a new kexec hook.
Well, the executive summary is that you have a guest whose memory *and*
registers are encrypted so the hypervisor cannot have a poke inside and
reset the vCPU like it would normally do. So you need to do that dance
differently, i.e, the patchset.
If you try to kexec such a guest now, it'll init only the BSP, as Joerg
said. So I guess a single-threaded kdump.
And yes, one of the prominent use cases is kdumping from such a guest,
as distros love doing kdump for debugging.
I hope that explains it better.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
WARNING: multiple messages have this Message-ID (diff)
From: Borislav Petkov <bp@alien8.de>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: kvm@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
virtualization@lists.linux-foundation.org,
Arvind Sankar <nivedita@alum.mit.edu>,
hpa@zytor.com, Jiri Slaby <jslaby@suse.cz>,
Joerg Roedel <joro@8bytes.org>,
x86@kernel.org, David Rientjes <rientjes@google.com>,
Martin Radev <martin.b.radev@gmail.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Joerg Roedel <jroedel@suse.de>, Kees Cook <keescook@chromium.org>,
Cfir Cohen <cfir@google.com>,
linux-coco@lists.linux.dev, Andy Lutomirski <luto@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
Juergen Gross <jgross@suse.com>, Mike Stunes <mstunes@vmware.com>,
Sean Christopherson <seanjc@google.com>,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org, Masami Hiramatsu <mhiramat@kernel.org>,
Erdem Aktas <erdemaktas@google.com>
Subject: Re: [PATCH v2 01/12] kexec: Allow architecture code to opt-out at runtime
Date: Tue, 2 Nov 2021 18:17:39 +0100 [thread overview]
Message-ID: <YYFys4KnpTftwJRz@zn.tnic> (raw)
In-Reply-To: <87pmrjbmy9.fsf@disp2133>
On Mon, Nov 01, 2021 at 04:11:42PM -0500, Eric W. Biederman wrote:
> I seem to remember the consensus when this was reviewed that it was
> unnecessary and there is already support for doing something like
> this at a more fine grained level so we don't need a new kexec hook.
Well, the executive summary is that you have a guest whose memory *and*
registers are encrypted so the hypervisor cannot have a poke inside and
reset the vCPU like it would normally do. So you need to do that dance
differently, i.e, the patchset.
If you try to kexec such a guest now, it'll init only the BSP, as Joerg
said. So I guess a single-threaded kdump.
And yes, one of the prominent use cases is kdumping from such a guest,
as distros love doing kdump for debugging.
I hope that explains it better.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
WARNING: multiple messages have this Message-ID (diff)
From: Borislav Petkov <bp@alien8.de>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Joerg Roedel <joro@8bytes.org>,
x86@kernel.org, kexec@lists.infradead.org,
Joerg Roedel <jroedel@suse.de>,
stable@vger.kernel.org, hpa@zytor.com,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Jiri Slaby <jslaby@suse.cz>,
Dan Williams <dan.j.williams@intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Juergen Gross <jgross@suse.com>,
Kees Cook <keescook@chromium.org>,
David Rientjes <rientjes@google.com>,
Cfir Cohen <cfir@google.com>, Erdem Aktas <erdemaktas@google.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mike Stunes <mstunes@vmware.com>,
Sean Christopherson <seanjc@google.com>,
Martin Radev <martin.b.radev@gmail.com>,
Arvind Sankar <nivedita@alum.mit.edu>,
linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v2 01/12] kexec: Allow architecture code to opt-out at runtime
Date: Tue, 2 Nov 2021 18:17:39 +0100 [thread overview]
Message-ID: <YYFys4KnpTftwJRz@zn.tnic> (raw)
In-Reply-To: <87pmrjbmy9.fsf@disp2133>
On Mon, Nov 01, 2021 at 04:11:42PM -0500, Eric W. Biederman wrote:
> I seem to remember the consensus when this was reviewed that it was
> unnecessary and there is already support for doing something like
> this at a more fine grained level so we don't need a new kexec hook.
Well, the executive summary is that you have a guest whose memory *and*
registers are encrypted so the hypervisor cannot have a poke inside and
reset the vCPU like it would normally do. So you need to do that dance
differently, i.e, the patchset.
If you try to kexec such a guest now, it'll init only the BSP, as Joerg
said. So I guess a single-threaded kdump.
And yes, one of the prominent use cases is kdumping from such a guest,
as distros love doing kdump for debugging.
I hope that explains it better.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
next prev parent reply other threads:[~2021-11-02 17:17 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-13 15:55 [PATCH v2 00/12] x86/sev: KEXEC/KDUMP support for SEV-ES guests Joerg Roedel
2021-09-13 15:55 ` Joerg Roedel
2021-09-13 15:55 ` [PATCH v2 01/12] kexec: Allow architecture code to opt-out at runtime Joerg Roedel
2021-09-13 15:55 ` Joerg Roedel
2021-11-01 16:10 ` Borislav Petkov
2021-11-01 16:10 ` Borislav Petkov
2021-11-01 16:10 ` Borislav Petkov
2021-11-01 21:11 ` Eric W. Biederman
2021-11-01 21:11 ` Eric W. Biederman
2021-11-01 21:11 ` Eric W. Biederman
2021-11-02 16:37 ` Joerg Roedel
2021-11-02 16:37 ` Joerg Roedel
2021-11-02 16:37 ` Joerg Roedel
2021-11-02 17:00 ` Joerg Roedel
2021-11-02 17:00 ` Joerg Roedel
2021-11-02 17:00 ` Joerg Roedel
2021-11-02 18:17 ` Eric W. Biederman
2021-11-02 18:17 ` Eric W. Biederman
2021-11-02 18:17 ` Eric W. Biederman
2021-11-02 17:17 ` Borislav Petkov [this message]
2021-11-02 17:17 ` Borislav Petkov
2021-11-02 17:17 ` Borislav Petkov
2021-09-13 15:55 ` [PATCH v2 02/12] x86/kexec/64: Forbid kexec when running as an SEV-ES guest Joerg Roedel
2021-09-13 15:55 ` Joerg Roedel
2021-09-13 15:55 ` [PATCH v2 03/12] x86/sev: Save and print negotiated GHCB protocol version Joerg Roedel
2021-09-13 15:55 ` Joerg Roedel
2021-11-03 14:27 ` Borislav Petkov
2021-11-03 14:27 ` Borislav Petkov
2021-11-03 14:27 ` Borislav Petkov
2022-01-26 9:27 ` Joerg Roedel
2022-01-26 9:27 ` Joerg Roedel
2022-01-26 9:27 ` Joerg Roedel
2021-09-13 15:55 ` [PATCH v2 04/12] x86/sev: Do not hardcode " Joerg Roedel
2021-09-13 15:55 ` Joerg Roedel
2021-09-13 15:55 ` [PATCH v2 05/12] x86/sev: Use GHCB protocol version 2 if supported Joerg Roedel
2021-09-13 15:55 ` Joerg Roedel
2021-11-03 16:05 ` Borislav Petkov
2021-11-03 16:05 ` Borislav Petkov
2021-11-03 16:05 ` Borislav Petkov
2021-09-13 15:55 ` [PATCH v2 06/12] x86/sev: Cache AP Jump Table Address Joerg Roedel
2021-09-13 15:55 ` Joerg Roedel
2021-11-08 18:14 ` Borislav Petkov
2021-11-08 18:14 ` Borislav Petkov
2021-11-08 18:14 ` Borislav Petkov
2021-09-13 15:55 ` [PATCH v2 07/12] x86/sev: Setup code to park APs in the AP Jump Table Joerg Roedel
2021-09-13 15:55 ` Joerg Roedel
2021-11-10 16:37 ` Borislav Petkov
2021-11-10 16:37 ` Borislav Petkov
2021-11-10 16:37 ` Borislav Petkov
2022-01-26 14:26 ` Joerg Roedel
2022-01-26 14:26 ` Joerg Roedel
2022-01-26 14:26 ` Joerg Roedel
2021-09-13 15:55 ` [PATCH v2 08/12] x86/sev: Park APs on AP Jump Table with GHCB protocol version 2 Joerg Roedel
2021-09-13 15:55 ` Joerg Roedel
2021-11-12 16:33 ` Borislav Petkov
2021-11-12 16:33 ` Borislav Petkov
2021-11-12 16:33 ` Borislav Petkov
2022-01-27 9:01 ` Joerg Roedel
2022-01-27 9:01 ` Joerg Roedel
2022-01-27 9:01 ` Joerg Roedel
2021-09-13 15:56 ` [PATCH v2 09/12] x86/sev: Use AP Jump Table blob to stop CPU Joerg Roedel
2021-09-13 15:56 ` Joerg Roedel
2021-11-15 18:44 ` Borislav Petkov
2021-11-15 18:44 ` Borislav Petkov
2021-11-15 18:44 ` Borislav Petkov
2021-09-13 15:56 ` [PATCH v2 10/12] x86/sev: Add MMIO handling support to boot/compressed/ code Joerg Roedel
2021-09-13 15:56 ` Joerg Roedel
2021-09-13 15:56 ` [PATCH v2 11/12] x86/sev: Handle CLFLUSH MMIO events Joerg Roedel
2021-09-13 15:56 ` Joerg Roedel
2021-09-13 15:56 ` [PATCH v2 12/12] x86/sev: Support kexec under SEV-ES with AP Jump Table blob Joerg Roedel
2021-09-13 15:56 ` Joerg Roedel
2021-09-13 16:02 ` [PATCH v2 00/12] x86/sev: KEXEC/KDUMP support for SEV-ES guests Dave Hansen
2021-09-13 16:02 ` Dave Hansen
2021-09-13 16:02 ` Dave Hansen
2021-09-13 16:14 ` Joerg Roedel
2021-09-13 16:14 ` Joerg Roedel
2021-09-13 16:14 ` Joerg Roedel
2021-09-13 16:21 ` Dave Hansen
2021-09-13 16:21 ` Dave Hansen
2021-09-13 16:21 ` Dave Hansen
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