From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "Rafael J. Wysocki" <rafael@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Adrian Hunter <adrian.hunter@intel.com>,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
Elena Reshetova <elena.reshetova@intel.com>,
Jun Nakajima <jun.nakajima@intel.com>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
"Kalra, Ashish" <ashish.kalra@amd.com>,
Sean Christopherson <seanjc@google.com>,
"Huang, Kai" <kai.huang@intel.com>, Baoquan He <bhe@redhat.com>,
kexec@lists.infradead.org, linux-coco@lists.linux.dev,
linux-kernel@vger.kernel.org, Tao Liu <ltao@redhat.com>
Subject: Re: [PATCHv10 10/18] x86/tdx: Convert shared memory back to private on kexec
Date: Wed, 8 May 2024 16:30:17 +0300 [thread overview]
Message-ID: <6pmeqhsvkm6noue6zhg6dqu5234isfjbdgush466l2tek3elij@uw7z2ooaqy4t> (raw)
In-Reply-To: <20240508120422.GCZjtqRrSuJeUyByEM@fat_crate.local>
On Wed, May 08, 2024 at 02:04:22PM +0200, Borislav Petkov wrote:
> On Mon, May 06, 2024 at 06:37:19PM +0300, Kirill A. Shutemov wrote:
> > "second kernel" is nomenclature kexec folks are using, but okay.
>
> And the "third kernel" is the one which got kexec-ed the second time?
>
> You can make it: "The second, kexec-ed kernel" and then it is perfectly
> clear.
Okay.
> > One possible reason for the failure is if kdump raced with memory
> > conversion. In this case shared bit in page table got set (or not cleared
> > form shared->private conversion), but the page is actually private. So
> > this failure is not going to affect the kexec'ed kernel.
>
> Lemme make sure I understand what you're saying here:
>
> 1. This is a fatal failure and we should panic
>
> However,
>
> 2. the kexec-ed kernel is using a different page table so there won't be
> a mismatch between shared/private marking of the page so it doesn't
> matter
>
> Close?
Yes.
One other point is even if the failure is real and we cannot touch the
page as private, kdump kernel will boot fine as it uses pre-reserved
memory. What happens next depends on what dumping process does. We have
reasonable chance to produce useful dump on crash.
--
Kiryl Shutsemau / Kirill A. Shutemov
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next prev parent reply other threads:[~2024-05-08 13:30 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240409113010.465412-1-kirill.shutemov@linux.intel.com>
2024-04-09 20:42 ` [PATCH v4 0/4] x86/snp: Add kexec support Ashish Kalra
2024-04-09 20:42 ` [PATCH v4 1/4] efi/x86: skip efi_arch_mem_reserve() in case of kexec Ashish Kalra
2024-04-09 20:42 ` [PATCH v4 2/4] x86/sev: add sev_es_enabled() function Ashish Kalra
2024-04-09 21:21 ` Borislav Petkov
2024-04-09 20:42 ` [PATCH v4 3/4] x86/boot/compressed: Skip Video Memory access in Decompressor for SEV-ES/SNP Ashish Kalra
2024-04-09 20:43 ` [PATCH v4 4/4] x86/snp: Convert shared memory back to private on kexec Ashish Kalra
2024-04-10 14:17 ` kernel test robot
2024-04-15 23:22 ` [PATCH v5 0/3] x86/snp: Add kexec support Ashish Kalra
2024-04-15 23:22 ` [PATCH v5 1/3] efi/x86: skip efi_arch_mem_reserve() in case of kexec Ashish Kalra
2024-04-24 14:48 ` Borislav Petkov
2024-04-24 21:17 ` Kalra, Ashish
2024-04-25 16:45 ` Kalra, Ashish
2024-04-26 14:21 ` Borislav Petkov
2024-04-26 14:47 ` Kalra, Ashish
2024-04-26 15:22 ` Borislav Petkov
2024-04-26 15:28 ` Kalra, Ashish
2024-04-26 15:34 ` Borislav Petkov
2024-04-26 16:32 ` Kalra, Ashish
2024-04-15 23:23 ` [PATCH v5 2/3] x86/boot/compressed: Skip Video Memory access in Decompressor for SEV-ES/SNP Ashish Kalra
2024-04-15 23:23 ` [PATCH v5 3/3] x86/snp: Convert shared memory back to private on kexec Ashish Kalra
2024-04-26 16:33 ` [PATCH v6 0/3] x86/snp: Add kexec support Ashish Kalra
2024-04-26 16:33 ` [PATCH v6 1/3] efi/x86: Fix EFI memory map corruption with kexec Ashish Kalra
2024-05-09 9:56 ` Ruirui Yang
2024-05-09 10:00 ` Dave Young
2024-05-10 18:36 ` Kalra, Ashish
2024-04-26 16:34 ` [PATCH v6 2/3] x86/boot/compressed: Skip Video Memory access in Decompressor for SEV-ES/SNP Ashish Kalra
2024-04-26 16:35 ` [PATCH v6 3/3] x86/snp: Convert shared memory back to private on kexec Ashish Kalra
2024-05-02 12:01 ` [PATCH v4 0/4] x86/snp: Add kexec support Alexander Graf
2024-05-02 12:18 ` Vitaly Kuznetsov
2024-05-03 8:32 ` Alexander Graf
2024-05-09 9:19 ` Vitaly Kuznetsov
2024-05-02 21:54 ` Kalra, Ashish
[not found] ` <20240409113010.465412-4-kirill.shutemov@linux.intel.com>
2024-04-18 14:37 ` [PATCHv10 03/18] cpu/hotplug: Add support for declaring CPU offlining not supported Borislav Petkov
2024-04-19 13:31 ` Kirill A. Shutemov
2024-04-23 13:17 ` Borislav Petkov
[not found] ` <20240409113010.465412-2-kirill.shutemov@linux.intel.com>
2024-04-18 16:03 ` [PATCHv10 01/18] x86/acpi: Extract ACPI MADT wakeup code into a separate file Borislav Petkov
2024-04-19 13:28 ` Kirill A. Shutemov
[not found] ` <20240409113010.465412-5-kirill.shutemov@linux.intel.com>
2024-04-23 16:02 ` [PATCHv10 04/18] cpu/hotplug, x86/acpi: Disable CPU offlining for ACPI MADT wakeup Borislav Petkov
2024-04-24 8:38 ` Kirill A. Shutemov
2024-04-24 13:50 ` Borislav Petkov
2024-04-24 14:35 ` Kirill A. Shutemov
2024-04-24 14:40 ` Dave Hansen
2024-04-24 14:51 ` Borislav Petkov
[not found] ` <20240409113010.465412-10-kirill.shutemov@linux.intel.com>
2024-04-27 16:47 ` [PATCHv10 09/18] x86/mm: Adding callbacks to prepare encrypted memory for kexec Borislav Petkov
[not found] ` <20240427170634.2397725-1-kirill.shutemov@linux.intel.com>
2024-05-02 13:45 ` [PATCHv10.1 " Borislav Petkov
2024-05-06 13:22 ` Kirill A. Shutemov
2024-05-06 14:21 ` Borislav Petkov
[not found] ` <20240409113010.465412-6-kirill.shutemov@linux.intel.com>
2024-04-09 12:38 ` [PATCHv10 05/18] x86/kexec: Keep CR4.MCE set during kexec for TDX guest Huang, Kai
2024-04-09 14:22 ` Sean Christopherson
2024-04-09 15:26 ` Kirill A. Shutemov
2024-04-28 17:11 ` Borislav Petkov
2024-04-29 13:17 ` Kirill A. Shutemov
2024-04-29 14:45 ` Borislav Petkov
2024-04-29 15:16 ` Kirill A. Shutemov
2024-04-30 12:57 ` Borislav Petkov
2024-04-30 13:03 ` Borislav Petkov
2024-04-30 14:49 ` Kirill A. Shutemov
2024-05-02 13:22 ` Borislav Petkov
2024-05-02 13:38 ` Borislav Petkov
[not found] ` <20240409113010.465412-7-kirill.shutemov@linux.intel.com>
2024-04-28 17:25 ` [PATCHv10 06/18] x86/mm: Make x86_platform.guest.enc_status_change_*() return errno Borislav Petkov
2024-04-29 14:29 ` Kirill A. Shutemov
2024-04-29 14:53 ` Borislav Petkov
2024-05-03 16:29 ` Michael Kelley
[not found] ` <20240409113010.465412-11-kirill.shutemov@linux.intel.com>
2024-05-05 12:13 ` [PATCHv10 10/18] x86/tdx: Convert shared memory back to private on kexec Borislav Petkov
2024-05-06 15:37 ` Kirill A. Shutemov
2024-05-08 12:04 ` Borislav Petkov
2024-05-08 13:30 ` Kirill A. Shutemov [this message]
[not found] ` <20240409113010.465412-12-kirill.shutemov@linux.intel.com>
2024-05-08 12:12 ` [PATCHv10 11/18] x86/mm: Make e820_end_ram_pfn() cover E820_TYPE_ACPI ranges Borislav Petkov
[not found] ` <20240409113010.465412-14-kirill.shutemov@linux.intel.com>
2024-05-08 12:18 ` [PATCHv10 13/18] x86/acpi: Rename fields in acpi_madt_multiproc_wakeup structure Borislav Petkov
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