From patchwork Sat May 24 08:21:57 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Mackerras X-Patchwork-Id: 4237281 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 685289F1CD for ; Sat, 24 May 2014 08:22:51 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 90CE02024D for ; Sat, 24 May 2014 08:22:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B9A3A2022D for ; Sat, 24 May 2014 08:22:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751398AbaEXIWq (ORCPT ); Sat, 24 May 2014 04:22:46 -0400 Received: from ozlabs.org ([103.22.144.67]:55967 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751263AbaEXIWW (ORCPT ); Sat, 24 May 2014 04:22:22 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPSA id 9A59C1400D2; Sat, 24 May 2014 18:22:20 +1000 (EST) From: Paul Mackerras To: Alexander Graf Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org Subject: [PATCH 3/7] KVM: PPC: Book3S HV: Fix check for running inside guest in global_invalidates() Date: Sat, 24 May 2014 18:21:57 +1000 Message-Id: <1400919721-14264-4-git-send-email-paulus@samba.org> X-Mailer: git-send-email 2.0.0.rc2 In-Reply-To: <1400919721-14264-1-git-send-email-paulus@samba.org> References: <1400919721-14264-1-git-send-email-paulus@samba.org> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham 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 The global_invalidates() function contains a check that is intended to tell whether we are currently executing in the context of a hypercall issued by the guest. The reason is that the optimization of using a local TLB invalidate instruction is only valid in that context. The check was testing local_paca->kvm_hstate.kvm_vcore, which gets set when entering the guest but no longer gets cleared when exiting the guest. To fix this, we use the kvm_vcpu field instead, which does get cleared when exiting the guest, by the kvmppc_release_hwthread() calls inside kvmppc_run_core(). The effect of having the check wrong was that when kvmppc_do_h_remove() got called from htab_write() on the destination machine during a migration, it cleared the current cpu's bit in kvm->arch.need_tlb_flush. This meant that when the guest started running in the destination VM, it may miss out on doing a complete TLB flush, and therefore may end up using stale TLB entries from a previous guest that used the same LPID value. This should make migration more reliable. Signed-off-by: Paul Mackerras --- arch/powerpc/kvm/book3s_hv_rm_mmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c index 1d6c56a..ac840c6 100644 --- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c +++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c @@ -42,13 +42,14 @@ static int global_invalidates(struct kvm *kvm, unsigned long flags) /* * If there is only one vcore, and it's currently running, + * as indicated by local_paca->kvm_hstate.kvm_vcpu being set, * we can use tlbiel as long as we mark all other physical * cores as potentially having stale TLB entries for this lpid. * If we're not using MMU notifiers, we never take pages away * from the guest, so we can use tlbiel if requested. * Otherwise, don't use tlbiel. */ - if (kvm->arch.online_vcores == 1 && local_paca->kvm_hstate.kvm_vcore) + if (kvm->arch.online_vcores == 1 && local_paca->kvm_hstate.kvm_vcpu) global = 0; else if (kvm->arch.using_mmu_notifiers) global = 1;