diff options
| author | Kirill A. Shutemov <[email protected]> | 2024-06-14 12:58:49 +0300 |
|---|---|---|
| committer | Borislav Petkov (AMD) <[email protected]> | 2024-06-17 17:45:34 +0200 |
| commit | 66e48e491d1e1a0f243ebfcb9639b23de1a5db5e (patch) | |
| tree | fa327aaabde7e3d6b6e03bacfcf51dd5dcb11266 | |
| parent | 1037e4c53e851682ff8d1ab656567a4d5a333c93 (diff) | |
cpu/hotplug, x86/acpi: Disable CPU offlining for ACPI MADT wakeup
ACPI MADT doesn't allow to offline a CPU after it has been woken up.
Currently, CPU 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. Any platform that uses ACPI MADT wakeup method cannot
offline CPU.
Disable CPU offlining on ACPI MADT wakeup enumeration.
This has no visible effects for users: currently, TDX guest is the only platform
that uses the ACPI MADT wakeup method.
Signed-off-by: Kirill A. Shutemov <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Tested-by: Tao Liu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
| -rw-r--r-- | arch/x86/coco/core.c | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/acpi/madt_wakeup.c | 3 | ||||
| -rw-r--r-- | include/linux/cc_platform.h | 10 | ||||
| -rw-r--r-- | kernel/cpu.c | 3 |
4 files changed, 4 insertions, 13 deletions
diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c index b31ef2424d19..0f81f70aca82 100644 --- a/arch/x86/coco/core.c +++ b/arch/x86/coco/core.c @@ -29,7 +29,6 @@ static bool noinstr intel_cc_platform_has(enum cc_attr attr) { switch (attr) { case CC_ATTR_GUEST_UNROLL_STRING_IO: - case CC_ATTR_HOTPLUG_DISABLED: case CC_ATTR_GUEST_MEM_ENCRYPT: case CC_ATTR_MEM_ENCRYPT: return true; diff --git a/arch/x86/kernel/acpi/madt_wakeup.c b/arch/x86/kernel/acpi/madt_wakeup.c index cf79ea6f3007..d222be8d7a07 100644 --- a/arch/x86/kernel/acpi/madt_wakeup.c +++ b/arch/x86/kernel/acpi/madt_wakeup.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0-or-later #include <linux/acpi.h> +#include <linux/cpu.h> #include <linux/io.h> #include <asm/apic.h> #include <asm/barrier.h> @@ -76,6 +77,8 @@ int __init acpi_parse_mp_wake(union acpi_subtable_headers *header, acpi_mp_wake_mailbox_paddr = mp_wake->base_address; + cpu_hotplug_disable_offlining(); + apic_update_callback(wakeup_secondary_cpu_64, acpi_wakeup_cpu); return 0; diff --git a/include/linux/cc_platform.h b/include/linux/cc_platform.h index 60693a145894..caa4b4430634 100644 --- a/include/linux/cc_platform.h +++ b/include/linux/cc_platform.h @@ -82,16 +82,6 @@ enum cc_attr { CC_ATTR_GUEST_SEV_SNP, /** - * @CC_ATTR_HOTPLUG_DISABLED: Hotplug is not supported or disabled. - * - * The platform/OS is running as a guest/virtual machine does not - * support CPU hotplug feature. - * - * Examples include TDX Guest. - */ - CC_ATTR_HOTPLUG_DISABLED, - - /** * @CC_ATTR_HOST_SEV_SNP: AMD SNP enabled on the host. * * The host kernel is running with the necessary features diff --git a/kernel/cpu.c b/kernel/cpu.c index 4c15b478e2bc..a609385c7f99 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1481,8 +1481,7 @@ 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) || - cpu_hotplug_offline_disabled) + if (cpu_hotplug_offline_disabled) return -EOPNOTSUPP; if (cpu_hotplug_disabled) return -EBUSY; |