From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: 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
Cc: "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,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCHv4 03/14] cpu/hotplug: Add support for declaring CPU offlining not supported
Date: Tue, 5 Dec 2023 03:44:59 +0300 [thread overview]
Message-ID: <20231205004510.27164-4-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <20231205004510.27164-1-kirill.shutemov@linux.intel.com>
The ACPI MADT mailbox wakeup method doesn't allow to offline CPU after
it got woke up.
Currently offlining hotplug is prevented based on the confidential
computing attribute which is set for Intel TDX. But TDX is not
the only possible user of the wake up method. The MADT wakeup can be
implemented outside of a confidential computing environment. Offline
support is a property of the wakeup method, not the CoCo implementation.
Introduce cpu_hotplug_disable_offlining() that can be called to indicate
that CPU offlining should be disabled.
This function is going to replace CC_ATTR_HOTPLUG_DISABLED for ACPI
MADT wakeup method.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
include/linux/cpu.h | 2 ++
kernel/cpu.c | 13 ++++++++++++-
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index fc8094419084..46f2e34a0c5e 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -134,6 +134,7 @@ extern void cpus_read_lock(void);
extern void cpus_read_unlock(void);
extern int cpus_read_trylock(void);
extern void lockdep_assert_cpus_held(void);
+extern void cpu_hotplug_disable_offlining(void);
extern void cpu_hotplug_disable(void);
extern void cpu_hotplug_enable(void);
void clear_tasks_mm_cpumask(int cpu);
@@ -149,6 +150,7 @@ static inline void cpus_read_lock(void) { }
static inline void cpus_read_unlock(void) { }
static inline int cpus_read_trylock(void) { return true; }
static inline void lockdep_assert_cpus_held(void) { }
+static inline void cpu_hotplug_disable_offlining(void) { }
static inline void cpu_hotplug_disable(void) { }
static inline void cpu_hotplug_enable(void) { }
static inline int remove_cpu(unsigned int cpu) { return -EPERM; }
diff --git a/kernel/cpu.c b/kernel/cpu.c
index a86972a91991..af8034ccda8e 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -484,6 +484,8 @@ static int cpu_hotplug_disabled;
DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock);
+static bool cpu_hotplug_offline_disabled;
+
void cpus_read_lock(void)
{
percpu_down_read(&cpu_hotplug_lock);
@@ -543,6 +545,14 @@ static void lockdep_release_cpus_lock(void)
rwsem_release(&cpu_hotplug_lock.dep_map, _THIS_IP_);
}
+/* Declare CPU offlining not supported */
+void cpu_hotplug_disable_offlining(void)
+{
+ cpu_maps_update_begin();
+ cpu_hotplug_offline_disabled = true;
+ cpu_maps_update_done();
+}
+
/*
* Wait for currently running CPU hotplug operations to complete (if any) and
* disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects
@@ -1522,7 +1532,8 @@ static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target)
* If the platform does not support hotplug, report it explicitly to
* differentiate it from a transient offlining failure.
*/
- if (cc_platform_has(CC_ATTR_HOTPLUG_DISABLED))
+ if (cc_platform_has(CC_ATTR_HOTPLUG_DISABLED) ||
+ cpu_hotplug_offline_disabled)
return -EOPNOTSUPP;
if (cpu_hotplug_disabled)
return -EBUSY;
--
2.41.0
next prev parent reply other threads:[~2023-12-05 0:45 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-05 0:44 [PATCHv4 00/14] x86/tdx: Add kexec support Kirill A. Shutemov
2023-12-05 0:44 ` [PATCHv4 01/14] x86/acpi: Extract ACPI MADT wakeup code into a separate file Kirill A. Shutemov
2023-12-05 0:44 ` [PATCHv4 02/14] x86/apic: Mark acpi_mp_wake_* variables as __ro_after_init Kirill A. Shutemov
2023-12-05 0:44 ` Kirill A. Shutemov [this message]
2023-12-15 19:42 ` [PATCHv4 03/14] cpu/hotplug: Add support for declaring CPU offlining not supported Thomas Gleixner
2023-12-05 0:45 ` [PATCHv4 04/14] cpu/hotplug, x86/acpi: Disable CPU offlining for ACPI MADT wakeup Kirill A. Shutemov
2023-12-15 19:43 ` Thomas Gleixner
2023-12-05 0:45 ` [PATCHv4 05/14] x86/kvm: Do not try to disable kvmclock if it was not enabled Kirill A. Shutemov
2023-12-11 23:10 ` Kirill A. Shutemov
2023-12-13 17:22 ` Sean Christopherson
2024-01-04 15:05 ` Kirill A. Shutemov
2024-01-09 14:59 ` Sean Christopherson
2023-12-05 0:45 ` [PATCHv4 06/14] x86/kexec: Keep CR4.MCE set during kexec for TDX guest Kirill A. Shutemov
2023-12-05 23:58 ` Huang, Kai
2023-12-06 13:26 ` kirill.shutemov
2023-12-05 0:45 ` [PATCHv4 07/14] x86/mm: Make x86_platform.guest.enc_status_change_*() return errno Kirill A. Shutemov
2023-12-05 0:45 ` [PATCHv4 08/14] x86/mm: Return correct level from lookup_address() if pte is none Kirill A. Shutemov
2023-12-05 0:45 ` [PATCHv4 09/14] x86/tdx: Account shared memory Kirill A. Shutemov
2023-12-05 0:45 ` [PATCHv4 10/14] x86/tdx: Convert shared memory back to private on kexec Kirill A. Shutemov
2023-12-06 1:28 ` Edgecombe, Rick P
2023-12-06 15:07 ` kirill.shutemov
2023-12-06 18:32 ` Edgecombe, Rick P
2023-12-05 0:45 ` [PATCHv4 11/14] x86/mm: Make e820_end_ram_pfn() cover E820_TYPE_ACPI ranges Kirill A. Shutemov
2023-12-05 0:45 ` [PATCHv4 12/14] x86/acpi: Rename fields in acpi_madt_multiproc_wakeup structure Kirill A. Shutemov
2023-12-05 0:45 ` [PATCHv4 13/14] x86/acpi: Do not attempt to bring up secondary CPUs in kexec case Kirill A. Shutemov
2023-12-15 20:08 ` Thomas Gleixner
2023-12-05 0:45 ` [PATCHv4 14/14] x86/acpi: Add support for CPU offlining for ACPI MADT wakeup method Kirill A. Shutemov
2023-12-05 23:36 ` Huang, Kai
2023-12-22 11:19 ` kirill.shutemov
2023-12-22 11:38 ` Huang, Kai
2023-12-15 20:29 ` Thomas Gleixner
2023-12-22 16:34 ` Kirill A. Shutemov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20231205004510.27164-4-kirill.shutemov@linux.intel.com \
--to=kirill.shutemov@linux.intel.com \
--cc=adrian.hunter@intel.com \
--cc=ashish.kalra@amd.com \
--cc=bhe@redhat.com \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=elena.reshetova@intel.com \
--cc=jun.nakajima@intel.com \
--cc=kai.huang@intel.com \
--cc=kexec@lists.infradead.org \
--cc=linux-coco@lists.linux.dev \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rafael@kernel.org \
--cc=rick.p.edgecombe@intel.com \
--cc=sathyanarayanan.kuppuswamy@linux.intel.com \
--cc=seanjc@google.com \
--cc=tglx@linutronix.de \
--cc=thomas.lendacky@amd.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).