From: Baoquan He <bhe@redhat.com>
To: "Huang, Kai" <kai.huang@intel.com>,
Nikolay Borisov <nik.borisov@suse.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
"Hunter, Adrian" <adrian.hunter@intel.com>,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
"Reshetova, Elena" <elena.reshetova@intel.com>,
"Nakajima, Jun" <jun.nakajima@intel.com>,
"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
"Kalra, Ashish" <ashish.kalra@amd.com>,
Sean Christopherson <seanjc@google.com>,
"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
"linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCHv6 00/16] x86/tdx: Add kexec support
Date: Wed, 31 Jan 2024 23:23:50 +0800 [thread overview]
Message-ID: <ZbpmBulaR7eft/CE@MiWiFi-R3L-srv> (raw)
In-Reply-To: <BL1PR11MB5978633DF36A69F8020818E1F77C2@BL1PR11MB5978.namprd11.prod.outlook.com>
On 01/31/24 at 01:07pm, Huang, Kai wrote:
> > > Runtime disabling kexec looks better than at cmpile time, esp for
> > > distros. While from above patch, making using of kexec_load_disabled
> > > to achive the runtime disabling may not be so good. Because we have a
> > > front door to enable it through:
> > >
> > > /proc/sys/kernel/kexec_load_disabled
> >
> > AFAIU it can't be enabled via this sysctl because the handler for it expects
> > only 1 to be written to it:
> >
> > 2 .proc_handler = proc_dointvec_minmax,
> >
> > 1 .extra1 = SYSCTL_ONE,
> >
> > 994 .extra2 = SYSCTL_ONE,
> >
>
> This is also my understanding.
>
> The documentation also says once it is turned to disable we cannot turn back again:
>
> kexec_load_disable
> ===================
>
> A toggle indicating if the syscalls ``kexec_load`` and
> ``kexec_file_load`` have been disabled.
> This value defaults to 0 (false: ``kexec_*load`` enabled), but can be
> set to 1 (true: ``kexec_*load`` disabled).
> Once true, kexec can no longer be used, and the toggle cannot be set
> back to false.
you are quite right, I have never noticed this, thanks.
Then then mentioned patch looks good to me.
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
prev parent reply other threads:[~2024-01-31 15:24 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240124125557.493675-1-kirill.shutemov@linux.intel.com>
[not found] ` <20240124125557.493675-15-kirill.shutemov@linux.intel.com>
2024-01-26 14:08 ` [PATCHv6 14/16] x86/smp: Add smp_ops.stop_this_cpu() callback Huang, Kai
[not found] ` <20240124125557.493675-16-kirill.shutemov@linux.intel.com>
2024-01-26 14:10 ` [PATCHv6 15/16] x86/mm: Introduce kernel_ident_mapping_free() Huang, Kai
[not found] ` <20240124125557.493675-17-kirill.shutemov@linux.intel.com>
2024-01-26 14:21 ` [PATCHv6 16/16] x86/acpi: Add support for CPU offlining for ACPI MADT wakeup method Huang, Kai
2024-01-27 18:15 ` kirill.shutemov
2024-01-26 20:03 ` Kuppuswamy Sathyanarayanan
2024-01-27 19:35 ` Kirill A. Shutemov
[not found] ` <20240124125557.493675-10-kirill.shutemov@linux.intel.com>
2024-01-29 7:22 ` [PATCHv6 09/16] x86/mm: Adding callbacks to prepare encrypted memory for kexec Nikolay Borisov
[not found] ` <20240124125557.493675-11-kirill.shutemov@linux.intel.com>
2024-01-29 10:24 ` [PATCHv6 10/16] x86/tdx: Convert shared memory back to private on kexec Kalra, Ashish
2024-01-29 10:36 ` Kirill A. Shutemov
2024-01-29 13:09 ` Kalra, Ashish
2024-01-29 13:34 ` Kirill A. Shutemov
2024-01-30 13:43 ` [PATCHv6 00/16] x86/tdx: Add kexec support Paolo Bonzini
2024-01-30 13:55 ` Kirill A. Shutemov
2024-01-30 14:59 ` Paolo Bonzini
2024-01-30 15:15 ` Kirill A. Shutemov
2024-01-30 14:04 ` Huang, Kai
2024-01-31 7:31 ` Nikolay Borisov
2024-01-31 12:47 ` Baoquan He
2024-01-31 12:58 ` Nikolay Borisov
2024-01-31 13:07 ` Huang, Kai
2024-01-31 15:23 ` Baoquan He [this message]
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