From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752829Ab2GOM5f (ORCPT ); Sun, 15 Jul 2012 08:57:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44474 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752460Ab2GOM4l (ORCPT ); Sun, 15 Jul 2012 08:56:41 -0400 Date: Sun, 15 Jul 2012 15:56:46 +0300 From: "Michael S. Tsirkin" To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Jacob Pan , Fernando Luis Vazquez Cao , Suresh Siddha , Joerg Roedel , Yinghai Lu , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, avi@redhat.com, gleb@redhat.com Subject: [PATCH 1/3] apic: add apic_set_eoi_write for PV use Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Mutt-Fcc: =sent Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- arch/x86/include/asm/apic.h | 3 +++ arch/x86/kernel/apic/apic.c | 17 +++++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index aa5b2ee..ff8dff6 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 39a222e..c7520b6 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2124,6 +2124,23 @@ void default_init_apic_ldr(void) } /* + * 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 */ #ifdef CONFIG_PM -- MST