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: [PATCHv6 13/16] x86/acpi: Do not attempt to bring up secondary CPUs in kexec case
Date: Wed, 24 Jan 2024 14:55:54 +0200 [thread overview]
Message-ID: <20240124125557.493675-14-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <20240124125557.493675-1-kirill.shutemov@linux.intel.com>
ACPI MADT doesn't allow to offline a CPU after it was onlined. This
limits kexec: the second kernel won't be able to use more than one CPU.
To prevent a kexec kernel from onlining secondary CPUs invalidate the
mailbox address in the ACPI MADT wakeup structure which prevents a
kexec kernel to use it.
This is safe as the booting kernel has the mailbox address cached
already and acpi_wakeup_cpu() uses the cached value to bring up the
secondary CPUs.
Note: This is a Linux specific convention and not covered by the
ACPI specification.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
arch/x86/kernel/acpi/madt_wakeup.c | 29 ++++++++++++++++++++++++++++-
1 file changed, 28 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/acpi/madt_wakeup.c b/arch/x86/kernel/acpi/madt_wakeup.c
index 004801b9b151..30820f9de5af 100644
--- a/arch/x86/kernel/acpi/madt_wakeup.c
+++ b/arch/x86/kernel/acpi/madt_wakeup.c
@@ -14,6 +14,11 @@ static struct acpi_madt_multiproc_wakeup_mailbox *acpi_mp_wake_mailbox __ro_afte
static int acpi_wakeup_cpu(u32 apicid, unsigned long start_ip)
{
+ if (!acpi_mp_wake_mailbox_paddr) {
+ pr_warn_once("No MADT mailbox: cannot bringup secondary CPUs. Booting with kexec?\n");
+ return -EOPNOTSUPP;
+ }
+
/*
* Remap mailbox memory only for the first call to acpi_wakeup_cpu().
*
@@ -64,6 +69,28 @@ static int acpi_wakeup_cpu(u32 apicid, unsigned long start_ip)
return 0;
}
+static void acpi_mp_disable_offlining(struct acpi_madt_multiproc_wakeup *mp_wake)
+{
+ cpu_hotplug_disable_offlining();
+
+ /*
+ * ACPI MADT doesn't allow to offline a CPU after it was onlined. This
+ * limits kexec: the second kernel won't be able to use more than one CPU.
+ *
+ * To prevent a kexec kernel from onlining secondary CPUs invalidate the
+ * mailbox address in the ACPI MADT wakeup structure which prevents a
+ * kexec kernel to use it.
+ *
+ * This is safe as the booting kernel has the mailbox address cached
+ * already and acpi_wakeup_cpu() uses the cached value to bring up the
+ * secondary CPUs.
+ *
+ * Note: This is a Linux specific convention and not covered by the
+ * ACPI specification.
+ */
+ mp_wake->mailbox_address = 0;
+}
+
int __init acpi_parse_mp_wake(union acpi_subtable_headers *header,
const unsigned long end)
{
@@ -77,7 +104,7 @@ int __init acpi_parse_mp_wake(union acpi_subtable_headers *header,
acpi_mp_wake_mailbox_paddr = mp_wake->mailbox_address;
- cpu_hotplug_disable_offlining();
+ acpi_mp_disable_offlining(mp_wake);
apic_update_callback(wakeup_secondary_cpu_64, acpi_wakeup_cpu);
--
2.43.0
next prev parent reply other threads:[~2024-01-24 12:57 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-24 12:55 [PATCHv6 00/16] x86/tdx: Add kexec support Kirill A. Shutemov
2024-01-24 12:55 ` [PATCHv6 01/16] x86/acpi: Extract ACPI MADT wakeup code into a separate file Kirill A. Shutemov
2024-01-24 12:55 ` [PATCHv6 02/16] x86/apic: Mark acpi_mp_wake_* variables as __ro_after_init Kirill A. Shutemov
2024-01-24 12:55 ` [PATCHv6 03/16] cpu/hotplug: Add support for declaring CPU offlining not supported Kirill A. Shutemov
2024-01-24 12:55 ` [PATCHv6 04/16] cpu/hotplug, x86/acpi: Disable CPU offlining for ACPI MADT wakeup Kirill A. Shutemov
2024-01-24 12:55 ` [PATCHv6 05/16] x86/kexec: Keep CR4.MCE set during kexec for TDX guest Kirill A. Shutemov
2024-01-24 12:55 ` [PATCHv6 06/16] x86/mm: Make x86_platform.guest.enc_status_change_*() return errno Kirill A. Shutemov
2024-01-24 12:55 ` [PATCHv6 07/16] x86/mm: Return correct level from lookup_address() if pte is none Kirill A. Shutemov
2024-01-24 12:55 ` [PATCHv6 08/16] x86/tdx: Account shared memory Kirill A. Shutemov
2024-01-24 12:55 ` [PATCHv6 09/16] x86/mm: Adding callbacks to prepare encrypted memory for kexec Kirill A. Shutemov
2024-01-29 7:22 ` Nikolay Borisov
2024-01-24 12:55 ` [PATCHv6 10/16] x86/tdx: Convert shared memory back to private on kexec Kirill A. Shutemov
2024-01-29 10:24 ` 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
2024-01-24 12:55 ` [PATCHv6 11/16] x86/mm: Make e820_end_ram_pfn() cover E820_TYPE_ACPI ranges Kirill A. Shutemov
2024-01-24 12:55 ` [PATCHv6 12/16] x86/acpi: Rename fields in acpi_madt_multiproc_wakeup structure Kirill A. Shutemov
2024-01-24 12:55 ` Kirill A. Shutemov [this message]
2024-01-24 12:55 ` [PATCHv6 14/16] x86/smp: Add smp_ops.stop_this_cpu() callback Kirill A. Shutemov
2024-01-26 14:08 ` Huang, Kai
2024-01-24 12:55 ` [PATCHv6 15/16] x86/mm: Introduce kernel_ident_mapping_free() Kirill A. Shutemov
2024-01-26 14:10 ` Huang, Kai
2024-01-24 12:55 ` [PATCHv6 16/16] x86/acpi: Add support for CPU offlining for ACPI MADT wakeup method Kirill A. Shutemov
2024-01-26 14:21 ` Huang, Kai
2024-01-27 18:15 ` kirill.shutemov
2024-01-26 20:03 ` Kuppuswamy Sathyanarayanan
2024-01-27 19:35 ` 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
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