From patchwork Tue Jun 15 07:34:11 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zachary Amsden X-Patchwork-Id: 106143 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter.kernel.org (8.14.3/8.14.3) with ESMTP id o5F7b8xt009112 for ; Tue, 15 Jun 2010 07:37:13 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752828Ab0FOHeq (ORCPT ); Tue, 15 Jun 2010 03:34:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43445 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755045Ab0FOHep (ORCPT ); Tue, 15 Jun 2010 03:34:45 -0400 Received: from int-mx04.intmail.prod.int.phx2.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.17]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o5F7YifQ032729 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 15 Jun 2010 03:34:45 -0400 Received: from mysore (vpn-8-141.rdu.redhat.com [10.11.8.141]) by int-mx04.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o5F7YL2j024602; Tue, 15 Jun 2010 03:34:42 -0400 From: Zachary Amsden To: avi@redhat.com, mtosatti@redhat.com, glommer@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Zachary Amsden Subject: [PATCH 09/17] Move scale_delta into common header. Date: Mon, 14 Jun 2010 21:34:11 -1000 Message-Id: <1276587259-32319-10-git-send-email-zamsden@redhat.com> In-Reply-To: <1276587259-32319-1-git-send-email-zamsden@redhat.com> References: <1276587259-32319-1-git-send-email-zamsden@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.17 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Tue, 15 Jun 2010 07:37:13 +0000 (UTC) diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h index cd02f32..7f7e577 100644 --- a/arch/x86/include/asm/pvclock.h +++ b/arch/x86/include/asm/pvclock.h @@ -12,4 +12,42 @@ void pvclock_read_wallclock(struct pvclock_wall_clock *wall, struct pvclock_vcpu_time_info *vcpu, struct timespec *ts); +/* + * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction, + * yielding a 64-bit result. + */ +static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift) +{ + u64 product; +#ifdef __i386__ + u32 tmp1, tmp2; +#endif + + if (shift < 0) + delta >>= -shift; + else + delta <<= shift; + +#ifdef __i386__ + __asm__ ( + "mul %5 ; " + "mov %4,%%eax ; " + "mov %%edx,%4 ; " + "mul %5 ; " + "xor %5,%5 ; " + "add %4,%%eax ; " + "adc %5,%%edx ; " + : "=A" (product), "=r" (tmp1), "=r" (tmp2) + : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) ); +#elif defined(__x86_64__) + __asm__ ( + "mul %%rdx ; shrd $32,%%rdx,%%rax" + : "=a" (product) : "0" (delta), "d" ((u64)mul_frac) ); +#else +#error implement me! +#endif + + return product; +} + #endif /* _ASM_X86_PVCLOCK_H */ diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c index 239427c..bab3b9e 100644 --- a/arch/x86/kernel/pvclock.c +++ b/arch/x86/kernel/pvclock.c @@ -82,7 +82,8 @@ static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift) static u64 pvclock_get_nsec_offset(struct pvclock_shadow_time *shadow) { u64 delta = native_read_tsc() - shadow->tsc_timestamp; - return scale_delta(delta, shadow->tsc_to_nsec_mul, shadow->tsc_shift); + return pvclock_scale_delta(delta, shadow->tsc_to_nsec_mul, + shadow->tsc_shift); } /*