From: Michael S. Tsirkin Date: Sun, 15 Jul 2012 12:56:46 +0000 (+0300) Subject: apic: add apic_set_eoi_write for PV use X-Git-Tag: master-2012-08-06~107^2~4 X-Git-Url: http://pileus.org/git/?a=commitdiff_plain;h=1551df646dd42122e17401013dba7a509d0f1b0d;p=~andy%2Flinux apic: add apic_set_eoi_write for PV use KVM PV EOI optimization overrides eoi_write apic op with its own version. Add an API for this to avoid meddling with core x86 apic driver data structures directly. For KVM use, we don't need any guarantees about when the switch to the new op will take place, so it could in theory use this API after SMP init, but it currently doesn't, and restricting callers to early init makes it clear that it's safe as it won't race with actual APIC driver use. Signed-off-by: Michael S. Tsirkin Acked-by: Ingo Molnar Signed-off-by: Avi Kivity --- diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index aa5b2eec360..ff8dff645e8 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -469,6 +469,8 @@ static inline u32 safe_apic_wait_icr_idle(void) return apic->safe_wait_icr_idle(); } +extern void __init apic_set_eoi_write(void (*eoi_write)(u32 reg, u32 v)); + #else /* CONFIG_X86_LOCAL_APIC */ static inline u32 apic_read(u32 reg) { return 0; } @@ -478,6 +480,7 @@ static inline u64 apic_icr_read(void) { return 0; } static inline void apic_icr_write(u32 low, u32 high) { } static inline void apic_wait_icr_idle(void) { } static inline u32 safe_apic_wait_icr_idle(void) { return 0; } +static inline void apic_set_eoi_write(void (*eoi_write)(u32 reg, u32 v)) {} #endif /* CONFIG_X86_LOCAL_APIC */ diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 39a222e094a..c7520b6184e 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2123,6 +2123,23 @@ void default_init_apic_ldr(void) apic_write(APIC_LDR, val); } +/* + * Override the generic EOI implementation with an optimized version. + * Only called during early boot when only one CPU is active and with + * interrupts disabled, so we know this does not race with actual APIC driver + * use. + */ +void __init apic_set_eoi_write(void (*eoi_write)(u32 reg, u32 v)) +{ + struct apic **drv; + + for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) { + /* Should happen once for each apic */ + WARN_ON((*drv)->eoi_write == eoi_write); + (*drv)->eoi_write = eoi_write; + } +} + /* * Power management */