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| author | David Woodhouse <dwmw@amazon.co.uk> | 2020-10-24 22:35:01 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-10-28 20:26:23 +0100 |
| commit | 26573a97746c7a99f394f9d398ce91a8853b3b89 (patch) | |
| tree | 1976a1d6ffcd6ffd621b526d082cb1e8ee8c6a42 /arch/x86/include/asm/apic.h | |
| parent | 5a169bf04cd2bfdbac967d12eb5b70915b29d7ee (diff) | |
| download | linux-stable-26573a97746c7a99f394f9d398ce91a8853b3b89.tar.gz linux-stable-26573a97746c7a99f394f9d398ce91a8853b3b89.tar.bz2 linux-stable-26573a97746c7a99f394f9d398ce91a8853b3b89.zip | |
x86/apic: Fix x2apic enablement without interrupt remapping
Currently, Linux as a hypervisor guest will enable x2apic only if there are
no CPUs present at boot time with an APIC ID above 255.
Hotplugging a CPU later with a higher APIC ID would result in a CPU which
cannot be targeted by external interrupts.
Add a filter in x2apic_apic_id_valid() which can be used to prevent such
CPUs from coming online, and allow x2apic to be enabled even if they are
present at boot time.
Fixes: ce69a784504 ("x86/apic: Enable x2APIC without interrupt remapping under KVM")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201024213535.443185-2-dwmw2@infradead.org
Diffstat (limited to 'arch/x86/include/asm/apic.h')
| -rw-r--r-- | arch/x86/include/asm/apic.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index 4e3099d9ae62..57af25cb44f6 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -259,6 +259,7 @@ static inline u64 native_x2apic_icr_read(void) extern int x2apic_mode; extern int x2apic_phys; +extern void __init x2apic_set_max_apicid(u32 apicid); extern void __init check_x2apic(void); extern void x2apic_setup(void); static inline int x2apic_enabled(void) |