From patchwork Tue Jun 17 10:03:58 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Graf X-Patchwork-Id: 4365651 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id D14519F36A for ; Tue, 17 Jun 2014 10:04:07 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 1838420204 for ; Tue, 17 Jun 2014 10:04:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1BE81201DE for ; Tue, 17 Jun 2014 10:04:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753135AbaFQKEB (ORCPT ); Tue, 17 Jun 2014 06:04:01 -0400 Received: from cantor2.suse.de ([195.135.220.15]:47302 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751737AbaFQKEA (ORCPT ); Tue, 17 Jun 2014 06:04:00 -0400 Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id F379BAABA; Tue, 17 Jun 2014 10:03:58 +0000 (UTC) From: Alexander Graf To: kvm-ppc@vger.kernel.org Cc: kvm@vger.kernel.org Subject: [PATCH v2] KVM: PPC: Book3s PR: Disable AIL mode with OPAL Date: Tue, 17 Jun 2014 12:03:58 +0200 Message-Id: <1402999438-51617-1-git-send-email-agraf@suse.de> X-Mailer: git-send-email 1.8.1.4 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.9 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 When we're using PR KVM we must not allow the CPU to take interrupts in virtual mode, as the SLB does not contain host kernel mappings when running inside the guest context. To make sure we get good performance for non-KVM tasks but still properly functioning PR KVM, let's just disable AIL whenever a vcpu is scheduled in. This is fundamentally different from how we deal with AIL on pSeries type machines where we disable AIL for the whole machine as soon as a single KVM VM is up. The reason for that is easy - on pSeries we do not have control over per-cpu configuration of AIL. We also don't want to mess with CPU hotplug races and AIL configuration, so setting it per CPU is easier and more flexible. This patch fixes running PR KVM on POWER8 bare metal for me. Signed-off-by: Alexander Graf Acked-by: Paul Mackerras --- v1 -> v2: - Extend patch description -- 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/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 3da412e..8ea7da4 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -71,6 +71,12 @@ static void kvmppc_core_vcpu_load_pr(struct kvm_vcpu *vcpu, int cpu) svcpu->in_use = 0; svcpu_put(svcpu); #endif + + /* Disable AIL if supported */ + if (cpu_has_feature(CPU_FTR_HVMODE) && + cpu_has_feature(CPU_FTR_ARCH_207S)) + mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) & ~LPCR_AIL); + vcpu->cpu = smp_processor_id(); #ifdef CONFIG_PPC_BOOK3S_32 current->thread.kvm_shadow_vcpu = vcpu->arch.shadow_vcpu; @@ -91,6 +97,12 @@ static void kvmppc_core_vcpu_put_pr(struct kvm_vcpu *vcpu) kvmppc_giveup_ext(vcpu, MSR_FP | MSR_VEC | MSR_VSX); kvmppc_giveup_fac(vcpu, FSCR_TAR_LG); + + /* Enable AIL if supported */ + if (cpu_has_feature(CPU_FTR_HVMODE) && + cpu_has_feature(CPU_FTR_ARCH_207S)) + mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_AIL_3); + vcpu->cpu = -1; }