From patchwork Mon Jan 6 14:00:02 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marcelo Tosatti X-Patchwork-Id: 3438171 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 6249CC02DD for ; Mon, 6 Jan 2014 14:19:49 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5D1CC2016C for ; Mon, 6 Jan 2014 14:19:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 305C420172 for ; Mon, 6 Jan 2014 14:19:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754645AbaAFOTf (ORCPT ); Mon, 6 Jan 2014 09:19:35 -0500 Received: from mx1.redhat.com ([209.132.183.28]:20308 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754629AbaAFOTe (ORCPT ); Mon, 6 Jan 2014 09:19:34 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s06EJYvN016913 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 6 Jan 2014 09:19:34 -0500 Received: from amt.cnet (vpn1-4-138.gru2.redhat.com [10.97.4.138]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s06EJX2v013340; Mon, 6 Jan 2014 09:19:33 -0500 Received: from amt.cnet (localhost [127.0.0.1]) by amt.cnet (Postfix) with ESMTP id 50F61104AD5; Mon, 6 Jan 2014 12:00:05 -0200 (BRST) Received: (from marcelo@localhost) by amt.cnet (8.14.6/8.14.6/Submit) id s06E04x7025011; Mon, 6 Jan 2014 12:00:04 -0200 Date: Mon, 6 Jan 2014 12:00:02 -0200 From: Marcelo Tosatti To: kvm-devel Cc: Paolo Bonzini , Jan Kiszka Subject: KVM: x86: limit PIT timer frequency Message-ID: <20140106140002.GA24790@amt.cnet> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Limit PIT timer frequency similarly to the limit applied by LAPIC timer. Cc: stable@kernel.org Signed-off-by: Marcelo Tosatti Reviewed-by: Jan Kiszka --- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 412a5aa..518d864 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -37,6 +37,7 @@ #include "irq.h" #include "i8254.h" +#include "x86.h" #ifndef CONFIG_X86_64 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y)) @@ -349,6 +350,23 @@ static void create_pit_timer(struct kvm *kvm, u32 val, int is_period) atomic_set(&ps->pending, 0); ps->irq_ack = 1; + /* + * Do not allow the guest to program periodic timers with small + * interval, since the hrtimers are not throttled by the host + * scheduler. + */ + if (ps->is_periodic) { + s64 min_period = min_timer_period_us * 1000LL; + + if (ps->period < min_period) { + pr_info_ratelimited( + "kvm: requested %lld ns " + "i8254 timer period limited to %lld ns\n", + ps->period, min_period); + ps->period = min_period; + } + } + hrtimer_start(&ps->timer, ktime_add_ns(ktime_get(), interval), HRTIMER_MODE_ABS); } diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index dec48bf..7f4dfa6 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -71,9 +71,6 @@ #define VEC_POS(v) ((v) & (32 - 1)) #define REG_POS(v) (((v) >> 5) << 4) -static unsigned int min_timer_period_us = 500; -module_param(min_timer_period_us, uint, S_IRUGO | S_IWUSR); - static inline void apic_set_reg(struct kvm_lapic *apic, int reg_off, u32 val) { *((u32 *) (apic->regs + reg_off)) = val; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 5d004da..d89d51b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -94,6 +94,9 @@ EXPORT_SYMBOL_GPL(kvm_x86_ops); static bool ignore_msrs = 0; module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR); +unsigned int min_timer_period_us = 500; +module_param(min_timer_period_us, uint, S_IRUGO | S_IWUSR); + bool kvm_has_tsc_control; EXPORT_SYMBOL_GPL(kvm_has_tsc_control); u32 kvm_max_guest_tsc_khz; diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index 587fb9e..8da5823 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -125,5 +125,7 @@ int kvm_write_guest_virt_system(struct x86_emulate_ctxt *ctxt, #define KVM_SUPPORTED_XCR0 (XSTATE_FP | XSTATE_SSE | XSTATE_YMM) extern u64 host_xcr0; +extern unsigned int min_timer_period_us; + extern struct static_key kvm_no_apic_vcpu; #endif