From: "Huang, Kai" <kai.huang@intel.com>
To: "kirill.shutemov@linux.intel.com"
<kirill.shutemov@linux.intel.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"x86@kernel.org" <x86@kernel.org>, "bp@alien8.de" <bp@alien8.de>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
"Reshetova, Elena" <elena.reshetova@intel.com>,
"Nakajima, Jun" <jun.nakajima@intel.com>,
"rafael@kernel.org" <rafael@kernel.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"sathyanarayanan.kuppuswamy@linux.intel.com"
<sathyanarayanan.kuppuswamy@linux.intel.com>,
"Hunter, Adrian" <adrian.hunter@intel.com>,
"thomas.lendacky@amd.com" <thomas.lendacky@amd.com>,
"ashish.kalra@amd.com" <ashish.kalra@amd.com>,
"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
"Christopherson,, Sean" <seanjc@google.com>,
"bhe@redhat.com" <bhe@redhat.com>,
"linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>
Subject: Re: [PATCHv2 11/13] x86/acpi: Do not attempt to bring up secondary CPUs in kexec case
Date: Tue, 24 Oct 2023 10:14:51 +0000 [thread overview]
Message-ID: <1185a15a1b4238092813a8134d86c93d73d84403.camel@intel.com> (raw)
In-Reply-To: <20231020151242.1814-12-kirill.shutemov@linux.intel.com>
On Fri, 2023-10-20 at 18:12 +0300, Kirill A. Shutemov wrote:
> ACPI MADT doesn't allow to offline CPU after it got woke up. It limits
> kexec: the second kernel won't be able to use more than one CPU.
>
> Now acpi_mp_wake_mailbox_paddr already has the mailbox address.
> The acpi_wakeup_cpu() will use it to bring up secondary cpus.
>
> Zero out mailbox address in the ACPI MADT wakeup structure to indicate
> that the mailbox is not usable. This prevents the kexec()-ed kernel
> from reading a vaild mailbox, which in turn makes the kexec()-ed kernel
> only be able to use the boot CPU.
>
> This is Linux-specific protocol and not reflected in ACPI spec.
>
> Booting the second kernel with signle CPU is enough to cover the most
> common case for kexec -- kdump.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
next prev parent reply other threads:[~2023-10-24 10:14 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-20 15:12 [PATCHv2 00/13] x86/tdx: Add kexec support Kirill A. Shutemov
2023-10-20 15:12 ` [PATCHv2 01/13] x86/acpi: Extract ACPI MADT wakeup code into a separate file Kirill A. Shutemov
2023-10-20 17:12 ` Kuppuswamy Sathyanarayanan
2023-10-20 15:12 ` [PATCHv2 02/13] kernel/cpu: Add support for declaring CPU offlining not supported Kirill A. Shutemov
2023-10-23 9:30 ` Huang, Kai
2023-10-23 15:31 ` kirill.shutemov
2023-10-23 22:07 ` Huang, Kai
2023-10-28 14:07 ` Thomas Gleixner
2023-10-28 14:12 ` Thomas Gleixner
2023-10-29 14:23 ` Kirill A. Shutemov
2023-10-20 15:12 ` [PATCHv2 03/13] cpu/hotplug, x86/acpi: Disable CPU offlining for ACPI MADT wakeup Kirill A. Shutemov
2023-10-20 15:12 ` [PATCHv2 04/13] x86/kvm: Do not try to disable kvmclock if it was not enabled Kirill A. Shutemov
2023-10-20 15:32 ` Sean Christopherson
2023-10-20 15:41 ` Vitaly Kuznetsov
2023-10-20 17:07 ` Sean Christopherson
2023-10-23 8:45 ` Vitaly Kuznetsov
2023-10-23 14:40 ` Sean Christopherson
2023-10-20 15:12 ` [PATCHv2 05/13] x86/kexec: Keep CR4.MCE set during kexec for TDX guest Kirill A. Shutemov
2023-10-20 15:12 ` [PATCHv2 06/13] x86/mm: Make x86_platform.guest.enc_status_change_*() return errno Kirill A. Shutemov
2023-10-20 15:12 ` [PATCHv2 07/13] x86/mm: Return correct level from lookup_address() if pte is none Kirill A. Shutemov
2023-10-20 15:12 ` [PATCHv2 08/13] x86/tdx: Account shared memory Kirill A. Shutemov
2023-10-20 15:12 ` [PATCHv2 09/13] x86/tdx: Convert shared memory back to private on kexec Kirill A. Shutemov
2023-10-20 15:12 ` [PATCHv2 10/13] x86/mm: Make e820_end_ram_pfn() cover E820_TYPE_ACPI ranges Kirill A. Shutemov
2023-10-20 15:12 ` [PATCHv2 11/13] x86/acpi: Do not attempt to bring up secondary CPUs in kexec case Kirill A. Shutemov
2023-10-24 10:14 ` Huang, Kai [this message]
2023-10-24 13:59 ` Kuppuswamy Sathyanarayanan
2023-10-27 13:01 ` Kirill A. Shutemov
2023-10-20 15:12 ` [PATCHv2 12/13] x86/acpi: Rename fields in acpi_madt_multiproc_wakeup structure Kirill A. Shutemov
2023-10-24 10:18 ` Huang, Kai
2023-10-24 12:46 ` Kuppuswamy Sathyanarayanan
2023-10-20 15:12 ` [PATCHv2 13/13] x86/acpi: Add support for CPU offlining for ACPI MADT wakeup method Kirill A. Shutemov
2023-10-24 10:11 ` Huang, Kai
2023-10-25 3:50 ` Huang, Kai
2023-10-27 11:58 ` kirill.shutemov
2023-10-29 17:31 ` Thomas Gleixner
2023-11-01 13:26 ` Kirill A. Shutemov
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