From: Joerg Roedel <jroedel@suse.de>
To: kexec@lists.infradead.org
Subject: [PATCH v2 07/12] x86/sev: Setup code to park APs in the AP Jump Table
Date: Wed, 26 Jan 2022 15:26:01 +0100 [thread overview]
Message-ID: <YfFZ+SRutJhDoAkz@suse.de> (raw)
In-Reply-To: <YYv1TPawuorQv1PR@zn.tnic>
On Wed, Nov 10, 2021 at 05:37:32PM +0100, Borislav Petkov wrote:
> On Mon, Sep 13, 2021 at 05:55:58PM +0200, Joerg Roedel wrote:
> > extern unsigned char real_mode_blob[];
> > diff --git a/arch/x86/include/asm/sev-ap-jumptable.h b/arch/x86/include/asm/sev-ap-jumptable.h
> > new file mode 100644
> > index 000000000000..1c8b2ce779e2
> > --- /dev/null
> > +++ b/arch/x86/include/asm/sev-ap-jumptable.h
>
> Why a separate header? arch/x86/include/asm/sev.h looks small enough.
The header is included in assembly, so I made a separate one.
> > +void __init sev_es_setup_ap_jump_table_data(void *base, u32 pa)
>
> Why is this a separate function?
>
> It is all part of the jump table setup.
Right, but the sev_es_setup_ap_jump_table_blob() function is already
pretty big and I wanted to keep things readable.
>
> > + return 0;
>
> Why are you returning 0 here and below?
This is in an initcall and it returns just 0 when the environment is not
ready to setup the ap jump table. Returning non-zero would create a
warning message in the caller for something that is not a bug in the
kernel.
> > + * This file contains the source code for the binary blob which gets copied to
> > + * the SEV-ES AP Jumptable to park APs while offlining CPUs or booting a new
>
> I've seen "Jumptable", "Jump Table" and "jump table" at least. I'd say, do
> the last one everywhere pls.
Fair, sorry for my english being too german :) I changed everything to
'jump table'.
> > + /* Reset remaining registers */
> > + movl $0, %esp
> > + movl $0, %eax
> > + movl $0, %ebx
> > + movl $0, %edx
>
> All 4: use xor
XOR changes EFLAGS, can not use them here.
> > +
> > + /* Reset CR0 to get out of protected mode */
> > + movl $0x60000010, %ecx
>
> Another magic naked number.
This is the CR0 reset value. I have updated the comment to make this
more clear.
Thanks,
--
J?rg R?del
jroedel at suse.de
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5
90409 N?rnberg
Germany
(HRB 36809, AG N?rnberg)
Gesch?ftsf?hrer: Ivo Totev
WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <jroedel@suse.de>
To: Borislav Petkov <bp@alien8.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 07/12] x86/sev: Setup code to park APs in the AP Jump Table
Date: Wed, 26 Jan 2022 15:26:01 +0100 [thread overview]
Message-ID: <YfFZ+SRutJhDoAkz@suse.de> (raw)
In-Reply-To: <YYv1TPawuorQv1PR@zn.tnic>
On Wed, Nov 10, 2021 at 05:37:32PM +0100, Borislav Petkov wrote:
> On Mon, Sep 13, 2021 at 05:55:58PM +0200, Joerg Roedel wrote:
> > extern unsigned char real_mode_blob[];
> > diff --git a/arch/x86/include/asm/sev-ap-jumptable.h b/arch/x86/include/asm/sev-ap-jumptable.h
> > new file mode 100644
> > index 000000000000..1c8b2ce779e2
> > --- /dev/null
> > +++ b/arch/x86/include/asm/sev-ap-jumptable.h
>
> Why a separate header? arch/x86/include/asm/sev.h looks small enough.
The header is included in assembly, so I made a separate one.
> > +void __init sev_es_setup_ap_jump_table_data(void *base, u32 pa)
>
> Why is this a separate function?
>
> It is all part of the jump table setup.
Right, but the sev_es_setup_ap_jump_table_blob() function is already
pretty big and I wanted to keep things readable.
>
> > + return 0;
>
> Why are you returning 0 here and below?
This is in an initcall and it returns just 0 when the environment is not
ready to setup the ap jump table. Returning non-zero would create a
warning message in the caller for something that is not a bug in the
kernel.
> > + * This file contains the source code for the binary blob which gets copied to
> > + * the SEV-ES AP Jumptable to park APs while offlining CPUs or booting a new
>
> I've seen "Jumptable", "Jump Table" and "jump table" at least. I'd say, do
> the last one everywhere pls.
Fair, sorry for my english being too german :) I changed everything to
'jump table'.
> > + /* Reset remaining registers */
> > + movl $0, %esp
> > + movl $0, %eax
> > + movl $0, %ebx
> > + movl $0, %edx
>
> All 4: use xor
XOR changes EFLAGS, can not use them here.
> > +
> > + /* Reset CR0 to get out of protected mode */
> > + movl $0x60000010, %ecx
>
> Another magic naked number.
This is the CR0 reset value. I have updated the comment to make this
more clear.
Thanks,
--
Jörg Rödel
jroedel@suse.de
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5
90409 Nürnberg
Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <jroedel@suse.de>
To: Borislav Petkov <bp@alien8.de>
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>,
Masami Hiramatsu <mhiramat@kernel.org>,
Martin Radev <martin.b.radev@gmail.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
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,
Eric Biederman <ebiederm@xmission.com>,
Erdem Aktas <erdemaktas@google.com>
Subject: Re: [PATCH v2 07/12] x86/sev: Setup code to park APs in the AP Jump Table
Date: Wed, 26 Jan 2022 15:26:01 +0100 [thread overview]
Message-ID: <YfFZ+SRutJhDoAkz@suse.de> (raw)
In-Reply-To: <YYv1TPawuorQv1PR@zn.tnic>
On Wed, Nov 10, 2021 at 05:37:32PM +0100, Borislav Petkov wrote:
> On Mon, Sep 13, 2021 at 05:55:58PM +0200, Joerg Roedel wrote:
> > extern unsigned char real_mode_blob[];
> > diff --git a/arch/x86/include/asm/sev-ap-jumptable.h b/arch/x86/include/asm/sev-ap-jumptable.h
> > new file mode 100644
> > index 000000000000..1c8b2ce779e2
> > --- /dev/null
> > +++ b/arch/x86/include/asm/sev-ap-jumptable.h
>
> Why a separate header? arch/x86/include/asm/sev.h looks small enough.
The header is included in assembly, so I made a separate one.
> > +void __init sev_es_setup_ap_jump_table_data(void *base, u32 pa)
>
> Why is this a separate function?
>
> It is all part of the jump table setup.
Right, but the sev_es_setup_ap_jump_table_blob() function is already
pretty big and I wanted to keep things readable.
>
> > + return 0;
>
> Why are you returning 0 here and below?
This is in an initcall and it returns just 0 when the environment is not
ready to setup the ap jump table. Returning non-zero would create a
warning message in the caller for something that is not a bug in the
kernel.
> > + * This file contains the source code for the binary blob which gets copied to
> > + * the SEV-ES AP Jumptable to park APs while offlining CPUs or booting a new
>
> I've seen "Jumptable", "Jump Table" and "jump table" at least. I'd say, do
> the last one everywhere pls.
Fair, sorry for my english being too german :) I changed everything to
'jump table'.
> > + /* Reset remaining registers */
> > + movl $0, %esp
> > + movl $0, %eax
> > + movl $0, %ebx
> > + movl $0, %edx
>
> All 4: use xor
XOR changes EFLAGS, can not use them here.
> > +
> > + /* Reset CR0 to get out of protected mode */
> > + movl $0x60000010, %ecx
>
> Another magic naked number.
This is the CR0 reset value. I have updated the comment to make this
more clear.
Thanks,
--
Jörg Rödel
jroedel@suse.de
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5
90409 Nürnberg
Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2022-01-26 14:26 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
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 [this message]
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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