From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber Costa Subject: [RFC 6/8] kvm steal time implementation Date: Mon, 30 Aug 2010 12:06:27 -0400 Message-ID: <1283184391-7785-12-git-send-email-glommer@redhat.com> References: <1283184391-7785-1-git-send-email-glommer@redhat.com> <1283184391-7785-2-git-send-email-glommer@redhat.com> <1283184391-7785-3-git-send-email-glommer@redhat.com> <1283184391-7785-4-git-send-email-glommer@redhat.com> <1283184391-7785-5-git-send-email-glommer@redhat.com> <1283184391-7785-6-git-send-email-glommer@redhat.com> <1283184391-7785-7-git-send-email-glommer@redhat.com> <1283184391-7785-8-git-send-email-glommer@redhat.com> <1283184391-7785-9-git-send-email-glommer@redhat.com> <1283184391-7785-10-git-send-email-glommer@redhat.com> <1283184391-7785-11-git-send-email-glommer@redhat.com> Cc: avi@redhat.com, zamsden@redhat.com, mtosatti@redhat.com, riel@redhat.com, peterz@infradead.org, mingo@elte.hu, jeremy@goop.org To: kvm@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:9106 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755910Ab0H3QXy (ORCPT ); Mon, 30 Aug 2010 12:23:54 -0400 In-Reply-To: <1283184391-7785-11-git-send-email-glommer@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: This is the proposed kvm-side steal time implementation. It is migration safe, as it checks flags at every read. Signed-off-by: Glauber Costa --- arch/x86/kernel/kvmclock.c | 35 +++++++++++++++++++++++++++++++++++ 1 files changed, 35 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index eb9b76c..a1f4852 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -18,6 +18,8 @@ #include #include +#include +#include #include #include #include @@ -41,6 +43,7 @@ early_param("no-kvmclock", parse_no_kvmclock); /* The hypervisor will put information about time periodically here */ static DEFINE_PER_CPU_SHARED_ALIGNED(struct pvclock_vcpu_time_info, hv_clock); +static DEFINE_PER_CPU(u64, steal_info); static struct pvclock_wall_clock wall_clock; /* @@ -82,6 +85,32 @@ static cycle_t kvm_clock_read(void) return ret; } +static DEFINE_PER_CPU(u64, steal_info); + +cputime_t kvm_get_steal_time(void) +{ + u64 delta = 0; + u64 *last_steal_info, this_steal_info; + struct pvclock_vcpu_time_info *src; + + src = &get_cpu_var(hv_clock); + if (!(src->flags & PVCLOCK_STEAL_BIT)) + goto out; + + this_steal_info = src->steal_time; + put_cpu_var(hv_clock); + + last_steal_info = &get_cpu_var(steal_info); + + delta = this_steal_info - *last_steal_info; + + *last_steal_info = this_steal_info; + put_cpu_var(steal_info); + +out: + return msecs_to_cputime(delta); +} + static cycle_t kvm_clock_get_cycles(struct clocksource *cs) { return kvm_clock_read(); @@ -134,6 +163,8 @@ static int kvm_register_clock(char *txt) printk(KERN_INFO "kvm-clock: cpu %d, msr %x:%x, %s\n", cpu, high, low, txt); + per_cpu(steal_info, cpu) = 0; + return native_write_msr_safe(msr_kvm_system_time, low, high); } @@ -218,4 +249,8 @@ void __init kvmclock_init(void) if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STABLE_BIT)) pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT); + + + if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STEAL_BIT)) + hypervisor_steal_time = kvm_get_steal_time; } -- 1.6.2.2