diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 67745ceab0db..b2c0fce3f257 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -462,8 +462,8 @@ config X86_X2APIC Some Intel systems circa 2022 and later are locked into x2APIC mode and can not fall back to the legacy APIC modes if SGX or TDX are - enabled in the BIOS. They will be unable to boot without enabling - this option. + enabled in the BIOS. They will boot with very reduced functionality + without enabling this option. If you don't know what to do here, say N. diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index 3415321c8240..3216da7074ba 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -249,7 +249,6 @@ 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) { @@ -258,13 +257,13 @@ static inline int x2apic_enabled(void) #define x2apic_supported() (boot_cpu_has(X86_FEATURE_X2APIC)) #else /* !CONFIG_X86_X2APIC */ -static inline void check_x2apic(void) { } static inline void x2apic_setup(void) { } static inline int x2apic_enabled(void) { return 0; } #define x2apic_mode (0) #define x2apic_supported() (0) #endif /* !CONFIG_X86_X2APIC */ +extern void __init check_x2apic(void); struct irq_data; diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index c6876d3ea4b1..20d9a604da7c 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1931,16 +1931,19 @@ void __init check_x2apic(void) } } #else /* CONFIG_X86_X2APIC */ -static int __init validate_x2apic(void) +void __init check_x2apic(void) { if (!apic_is_x2apic_enabled()) - return 0; + return; /* - * Checkme: Can we simply turn off x2apic here instead of panic? + * Checkme: Can we simply turn off x2APIC here instead of disabling the APIC? */ - panic("BIOS has enabled x2apic but kernel doesn't support x2apic, please disable x2apic in BIOS.\n"); + pr_err("Kernel does not support x2APIC, please recompile with CONFIG_X86_X2APIC.\n"); + pr_err("Disabling APIC, expect reduced performance and functionality.\n"); + + disable_apic = 1; + setup_clear_cpu_cap(X86_FEATURE_APIC); } -early_initcall(validate_x2apic); static inline void try_to_enable_x2apic(int remap_mode) { } static inline void __x2apic_enable(void) { }