From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A0760C433EF for ; Sat, 20 Nov 2021 04:52:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237212AbhKTEzp (ORCPT ); Fri, 19 Nov 2021 23:55:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55170 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237043AbhKTEyr (ORCPT ); Fri, 19 Nov 2021 23:54:47 -0500 Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 53BF8C061758 for ; Fri, 19 Nov 2021 20:51:29 -0800 (PST) Received: by mail-pg1-x549.google.com with SMTP id s8-20020a63af48000000b002e6c10ac245so5029519pgo.21 for ; Fri, 19 Nov 2021 20:51:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=reply-to:date:in-reply-to:message-id:mime-version:references :subject:from:to:cc; bh=AYx9sJvbwxB0sjhZtd5DFNw6mN6V1huadyjHwAl8qyw=; b=f+RKeHOw+lES1XSli4Wpoaxhwl+WeKvn1k9OMhsgTilJMSFmV3iHgjFoLtCpkxl3WE V5bBEh+2u7V5C527aOhUlnyV1RufARW1OjFiKJdmn7ScVYBEJrrfrC6kcsD9XC9yYoG2 t3OnPoUfRnBKevyG03GekYE/qSYf1buEGsap0wIQF5akx9JOuKFyvJxNVnVsWyWVI1iT N2ry8L7wQOWzWU7135htytqvIu0pSawNjiCtQso5UHn7DLF/XAEqXCkdnc+YHbzHV3N7 0ExIfdUX6xlJ4XqGizNqYDQxrvngZkem6nSWQ4K/LjWy7PlS09g0nX/4c4GKhh6XZHpM woxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:reply-to:date:in-reply-to:message-id :mime-version:references:subject:from:to:cc; bh=AYx9sJvbwxB0sjhZtd5DFNw6mN6V1huadyjHwAl8qyw=; b=Y+quBOj3i0cffIAgwmShgNzyLuGEOfT4pZ4XoRJLMuX7JBsVYIF6Rk4i5xivghoWGR D3A2v8f1/m0J2cJAHGY+PjZqoJ4kAcUtho66T6km56wbHLgFwSql9LQ3xnxan9oQmzlT zLImaYyM9lFFrDgWJeq3jTSisgYCRnQV9APv9S0oaLp4CdOLH0LybXKIUXFbud2iUEEX LonwMejAakivWM3i0sOicKZuXhx4CCSr5xfCREbwIQZzV8hf5ZPNl+HvAL7U0SYAn4uT s7izIf3eHIZRVXzU3PcAI3dDp8E6KFjEUN1MLF4AQMa7XRGKD6lDj54y3WhaAHhvKlZX XdaQ== X-Gm-Message-State: AOAM5315cSO3Wz7FeLTZe9BFBmmY5nR3vXF5jbj3+2nFvKPIbCEpRHIU vwGzz4pXH0YDTyeDu+eo+gxQnoik2lU= X-Google-Smtp-Source: ABdhPJwaSJWhoYJY/fMx/Lp60XbTR6Qc8p1gEC2NAp15y6/XV+Y5Mcb3KxEIwLy8gZ54AMTzhL+9ZdZc1Gc= X-Received: from seanjc.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:3e5]) (user=seanjc job=sendgmr) by 2002:a63:63c1:: with SMTP id x184mr20729341pgb.401.1637383888887; Fri, 19 Nov 2021 20:51:28 -0800 (PST) Reply-To: Sean Christopherson Date: Sat, 20 Nov 2021 04:50:40 +0000 In-Reply-To: <20211120045046.3940942-1-seanjc@google.com> Message-Id: <20211120045046.3940942-23-seanjc@google.com> Mime-Version: 1.0 References: <20211120045046.3940942-1-seanjc@google.com> X-Mailer: git-send-email 2.34.0.rc2.393.gf8c9666880-goog Subject: [PATCH 22/28] KVM: x86/mmu: Skip remote TLB flush when zapping all of TDP MMU From: Sean Christopherson To: Paolo Bonzini Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Hou Wenlong , Ben Gardon Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Don't flush the TLBs when zapping all TDP MMU pages, as the only time KVM uses the slow version of "zap everything" is when the VM is being destroyed or the owning mm has exited. In either case, KVM_RUN is unreachable for the VM, i.e. the guest TLB entries cannot be consumed. Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu/tdp_mmu.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 31fb622249e5..e5401f0efe8e 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -888,14 +888,15 @@ bool __kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, int as_id, gfn_t start, void kvm_tdp_mmu_zap_all(struct kvm *kvm) { - bool flush = false; int i; + /* + * A TLB flush is unnecessary, KVM's zap everything if and only the VM + * is being destroyed or the userspace VMM has exited. In both cases, + * KVM_RUN is unreachable, i.e. no vCPUs will ever service the request. + */ for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) - flush = kvm_tdp_mmu_zap_gfn_range(kvm, i, 0, -1ull, flush); - - if (flush) - kvm_flush_remote_tlbs(kvm); + (void)kvm_tdp_mmu_zap_gfn_range(kvm, i, 0, -1ull, false); } /* -- 2.34.0.rc2.393.gf8c9666880-goog