From: Dave Hansen <dave.hansen@intel.com>
To: Joerg Roedel <jroedel@suse.de>
Cc: Joerg Roedel <joro@8bytes.org>,
x86@kernel.org, Eric Biederman <ebiederm@xmission.com>,
kexec@lists.infradead.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 00/12] x86/sev: KEXEC/KDUMP support for SEV-ES guests
Date: Mon, 13 Sep 2021 09:21:27 -0700 [thread overview]
Message-ID: <9aa5c10b-56ee-8b26-56d5-870c44e6fbcc@intel.com> (raw)
In-Reply-To: <YT941raolZvGTVR/@suse.de>
On 9/13/21 9:14 AM, Joerg Roedel wrote:
> On Mon, Sep 13, 2021 at 09:02:38AM -0700, Dave Hansen wrote:
>> On 9/13/21 8:55 AM, Joerg Roedel wrote:
>>> This does not work under SEV-ES, because the hypervisor has no access
>>> to the vCPU registers and can't make modifications to them. So an
>>> SEV-ES guest needs to reset the vCPU itself and park it using the
>>> AP-reset-hold protocol. Upon wakeup the guest needs to jump to
>>> real-mode and to the reset-vector configured in the AP-Jump-Table.
>> How does this end up looking to an end user that tries to kexec() from a
>> an SEV-ES kernel? Does it just hang?
> Yes, the kexec will just hang. This patch-set contains code to disable
> the kexec syscalls in situations where it would not work for that
> reason.
Got it. The end-user-visible symptom just wasn't obvious. If you
revise these, it might be nice to add that so that folks who cherry-pick
stable patches or update to new stable kernels have an idea what this
might fix.
prev parent reply other threads:[~2021-09-13 16:21 UTC|newest]
Thread overview: 31+ 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 ` [PATCH v2 01/12] kexec: Allow architecture code to opt-out at runtime Joerg Roedel
2021-11-01 16:10 ` Borislav Petkov
2021-11-01 21:11 ` Eric W. Biederman
2021-11-02 16:37 ` Joerg Roedel
2021-11-02 17:00 ` Joerg Roedel
2021-11-02 18:17 ` Eric W. Biederman
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 ` [PATCH v2 03/12] x86/sev: Save and print negotiated GHCB protocol version Joerg Roedel
2021-11-03 14:27 ` Borislav Petkov
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 ` [PATCH v2 05/12] x86/sev: Use GHCB protocol version 2 if supported Joerg Roedel
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
2021-11-08 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
2021-11-10 16:37 ` Borislav Petkov
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
2021-11-12 16:33 ` Borislav Petkov
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
2021-11-15 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 ` [PATCH v2 11/12] x86/sev: Handle CLFLUSH MMIO events 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 16:02 ` [PATCH v2 00/12] x86/sev: KEXEC/KDUMP support for SEV-ES guests Dave Hansen
2021-09-13 16:14 ` Joerg Roedel
2021-09-13 16:21 ` Dave Hansen [this message]
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