From: "Huang, Kai" <kai.huang@intel.com>
To: "kirill.shutemov@linux.intel.com" <kirill.shutemov@linux.intel.com>
Cc: "kexec@lists.infradead.org" <kexec@lists.infradead.org>,
"linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>,
"ashish.kalra@amd.com" <ashish.kalra@amd.com>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
"thomas.lendacky@amd.com" <thomas.lendacky@amd.com>,
"Hunter, Adrian" <adrian.hunter@intel.com>,
"Reshetova, Elena" <elena.reshetova@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"seanjc@google.com" <seanjc@google.com>,
"mingo@redhat.com" <mingo@redhat.com>,
"bhe@redhat.com" <bhe@redhat.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"Nakajima, Jun" <jun.nakajima@intel.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
"bp@alien8.de" <bp@alien8.de>,
"rafael@kernel.org" <rafael@kernel.org>,
"sathyanarayanan.kuppuswamy@linux.intel.com"
<sathyanarayanan.kuppuswamy@linux.intel.com>,
"x86@kernel.org" <x86@kernel.org>
Subject: Re: [PATCHv5.1 14/16] x86/smp: Add smp_ops.stop_this_cpu() callback
Date: Tue, 9 Jan 2024 03:04:15 +0000 [thread overview]
Message-ID: <aca16663465ff579da076bb66f851ff71072ef8d.camel@intel.com> (raw)
In-Reply-To: <20240108101553.4zgji5emlw7cjlik@box.shutemov.name>
> > > @@ -835,6 +835,13 @@ void __noreturn stop_this_cpu(void *dummy)
> > > */
> > > cpumask_clear_cpu(cpu, &cpus_stop_mask);
> > >
> > > +#ifdef CONFIG_SMP
> > > + if (smp_ops.stop_this_cpu) {
> > > + smp_ops.stop_this_cpu();
> > > + unreachable();
> > > + }
> > > +#endif
> >
> > If I read correctly this will result in stop_this_cpu() having different
> > behaviour for SMP and !SMP build for TDX guest. For example, AFAICT
> > machine_halt() also calls stop_this_cpu() on local cpu after it stops other
> > cpus. So for the local cpu, in SMP build it will calls into BIOS's reset vector
> > but in !SMP it will call native_halt().
>
> It doesn't make a difference in practice: both halt and giving CPU to
> BIOS will be unrecoverable operation. Both are equally acceptable for
> machine_halt().
>
OK fair enough. :-)
next prev parent reply other threads:[~2024-01-09 3:04 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-22 23:51 [PATCHv5 00/16] x86/tdx: Add kexec support Kirill A. Shutemov
2023-12-22 23:51 ` [PATCHv5 01/16] x86/acpi: Extract ACPI MADT wakeup code into a separate file Kirill A. Shutemov
2023-12-22 23:51 ` [PATCHv5 02/16] x86/apic: Mark acpi_mp_wake_* variables as __ro_after_init Kirill A. Shutemov
2023-12-22 23:51 ` [PATCHv5 03/16] cpu/hotplug: Add support for declaring CPU offlining not supported Kirill A. Shutemov
2023-12-22 23:51 ` [PATCHv5 04/16] cpu/hotplug, x86/acpi: Disable CPU offlining for ACPI MADT wakeup Kirill A. Shutemov
2023-12-22 23:51 ` [PATCHv5 05/16] x86/kvm: Do not try to disable kvmclock if it was not enabled Kirill A. Shutemov
2023-12-22 23:51 ` [PATCHv5 06/16] x86/kexec: Keep CR4.MCE set during kexec for TDX guest Kirill A. Shutemov
2023-12-22 23:51 ` [PATCHv5 07/16] x86/mm: Make x86_platform.guest.enc_status_change_*() return errno Kirill A. Shutemov
2023-12-22 23:52 ` [PATCHv5 08/16] x86/mm: Return correct level from lookup_address() if pte is none Kirill A. Shutemov
2023-12-22 23:52 ` [PATCHv5 09/16] x86/tdx: Account shared memory Kirill A. Shutemov
2023-12-22 23:52 ` [PATCHv5 10/16] x86/tdx: Convert shared memory back to private on kexec Kirill A. Shutemov
2024-01-05 19:38 ` Edgecombe, Rick P
2024-01-06 0:59 ` kirill.shutemov
2024-01-06 1:12 ` Edgecombe, Rick P
2024-01-15 10:53 ` Nikolay Borisov
2024-01-16 7:28 ` Kirill A. Shutemov
2024-01-16 8:01 ` Nikolay Borisov
2024-01-16 10:45 ` Kirill A. Shutemov
2024-01-16 10:53 ` Kirill A. Shutemov
2023-12-22 23:52 ` [PATCHv5 11/16] x86/mm: Make e820_end_ram_pfn() cover E820_TYPE_ACPI ranges Kirill A. Shutemov
2023-12-22 23:52 ` [PATCHv5 12/16] x86/acpi: Rename fields in acpi_madt_multiproc_wakeup structure Kirill A. Shutemov
2023-12-22 23:52 ` [PATCHv5 13/16] x86/acpi: Do not attempt to bring up secondary CPUs in kexec case Kirill A. Shutemov
2023-12-22 23:52 ` [PATCHv5 14/16] x86/smp: Add smp_ops.stop_this_cpu() callback Kirill A. Shutemov
2023-12-25 8:05 ` [PATCHv5.1 " Kirill A. Shutemov
2024-01-08 3:04 ` Huang, Kai
2024-01-08 10:15 ` kirill.shutemov
2024-01-09 3:04 ` Huang, Kai [this message]
2023-12-22 23:52 ` [PATCHv5 15/16] x86/mm: Introduce kernel_ident_mapping_free() Kirill A. Shutemov
2024-01-08 3:13 ` Huang, Kai
2024-01-08 3:30 ` Huang, Kai
2024-01-08 10:17 ` kirill.shutemov
2024-01-08 13:13 ` Huang, Kai
2024-01-08 13:35 ` kirill.shutemov
2023-12-22 23:52 ` [PATCHv5 16/16] x86/acpi: Add support for CPU offlining for ACPI MADT wakeup method Kirill A. Shutemov
2024-01-15 13:19 ` Nikolay Borisov
2024-01-16 6:50 ` Kirill A. Shutemov
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