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 B0BB3C43217 for ; Thu, 9 Dec 2021 06:06:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232666AbhLIGJg (ORCPT ); Thu, 9 Dec 2021 01:09:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57920 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232642AbhLIGJe (ORCPT ); Thu, 9 Dec 2021 01:09:34 -0500 Received: from mail-pj1-x1049.google.com (mail-pj1-x1049.google.com [IPv6:2607:f8b0:4864:20::1049]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EBB26C0617A1 for ; Wed, 8 Dec 2021 22:06:01 -0800 (PST) Received: by mail-pj1-x1049.google.com with SMTP id b8-20020a17090a10c800b001a61dff6c9dso3035970pje.5 for ; Wed, 08 Dec 2021 22:06:01 -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=PUYcIIJKsxBIAAizj0Y9Eh5D3GRB3JGARLuO03M6nuk=; b=lJtw45QEza3KMEyzVaRdR8j9tBIr2Fmk1JFaJKCN0HHUj+MaCw/aS8rUhnS/+uInJx covrIZyP3ITtMtl9YU0/Nqno2QP4OCaO+4rJ6IKCdz47EvW64j3blNt/qeficIY9iED9 eduzYL2rCvLF//D7ktTMwRgoJmxURatdPraNKnYXCJzw3bh3jrVJ2klj7qD4u6yw5i7S gVRc9g+YV0eViIIGIMFBat6dG8+jOinBDrd65BAWV2A8SnYXntrKoYf21b3u/VqA6Wlb w3kWDsDmf61P1YxbhH5fj4CFMF8vmXD6G7IwgPEyvCJTLlC/KOksmwvCBaxD8Iib5jBO C4Kg== 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=PUYcIIJKsxBIAAizj0Y9Eh5D3GRB3JGARLuO03M6nuk=; b=QdiQNkFjQJ0jBu1bDHqxiCxNrqJiHKsQZmSvPz4BRlstrJ70+0wGxx68xrAfOEbAx9 BaNhh0FLDF9uXhwjLXc1yJWNhjNF5KZLpcaU33CKRy2je7BrbyBUYdQsMN4WdWZpnFVw YDevP85fNF0bJHMEaw0qLOdBJi6Bs1TTjhLGcjo7qAVNvIQmmVvMwX2FkUg2BP43Tyzb zktlS+JXfTcp/FKiN4T6D/ip/6E0fW4huqHlN1c4SChlDmqeMlzw2gvTo+opg1FT1THJ vGwaRc/J8OiUQ3g/9GCcOhSoDEzn65+euRne6ljkN+mvxSLRKMbwGmkkBqRU13iv0p+x 5eMA== X-Gm-Message-State: AOAM532MeiHyltlMGvg/1inh3dAGl8ny9BhFT8+KFey+Z4EaR4OmOq6B SoFM2L9w5iMKCvOZs5Q741v5+ivUPxk= X-Google-Smtp-Source: ABdhPJyv6Njx687Wa+aodBEX3C/mF2v7CuZORX5Al6AG4vlZ6nFlmJ2Gt0e9cDjHkK7cE4j1JskeZZNTiMI= X-Received: from seanjc.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:3e5]) (user=seanjc job=sendgmr) by 2002:a17:90b:1057:: with SMTP id gq23mr12968391pjb.203.1639029961379; Wed, 08 Dec 2021 22:06:01 -0800 (PST) Reply-To: Sean Christopherson Date: Thu, 9 Dec 2021 06:05:47 +0000 In-Reply-To: <20211209060552.2956723-1-seanjc@google.com> Message-Id: <20211209060552.2956723-3-seanjc@google.com> Mime-Version: 1.0 References: <20211209060552.2956723-1-seanjc@google.com> X-Mailer: git-send-email 2.34.1.400.ga245620fadb-goog Subject: [PATCH 2/7] KVM: x86: Invoke kvm_mmu_unload() directly on CR4.PCIDE change From: Sean Christopherson To: Paolo Bonzini , Christian Borntraeger , Janosch Frank Cc: David Hildenbrand , Claudio Imbrenda , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Maxim Levitsky , Ben Gardon , Lai Jiangshan Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Replace a KVM_REQ_MMU_RELOAD request with a direct kvm_mmu_unload() call when the guest's CR4.PCIDE changes. This will allow tweaking the logic of KVM_REQ_MMU_RELOAD to free only obsolete/invalid roots, which is the historical intent of KVM_REQ_MMU_RELOAD. The recent PCIDE behavior is the only user of KVM_REQ_MMU_RELOAD that doesn't mark affected roots as obsolete, needs to unconditionally unload the entire MMU, _and_ affects only the current vCPU. Signed-off-by: Sean Christopherson --- arch/x86/kvm/x86.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1aaf37e1bd0f..ca1f0350a868 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1045,19 +1045,18 @@ void kvm_post_set_cr4(struct kvm_vcpu *vcpu, unsigned long old_cr4, unsigned lon * If CR4.PCIDE is changed 0 -> 1, there is no need to flush the TLB * according to the SDM; however, stale prev_roots could be reused * incorrectly in the future after a MOV to CR3 with NOFLUSH=1, so we - * free them all. KVM_REQ_MMU_RELOAD is fit for the both cases; it - * is slow, but changing CR4.PCIDE is a rare case. + * free them all. kvm_mmu_unload() is fit for the both cases; it is + * slow, but changing CR4.PCIDE is a rare case. * * If CR4.PGE is changed, the guest TLB must be flushed. * - * Note: resetting MMU is a superset of KVM_REQ_MMU_RELOAD and - * KVM_REQ_MMU_RELOAD is a superset of KVM_REQ_TLB_FLUSH_GUEST, hence - * the usage of "else if". + * Note: resetting MMU is a superset of unloading an MMU, and unloading + * an MMU is a superset of KVM_REQ_TLB_FLUSH_GUEST, hence the "else if". */ if ((cr4 ^ old_cr4) & KVM_MMU_CR4_ROLE_BITS) kvm_mmu_reset_context(vcpu); else if ((cr4 ^ old_cr4) & X86_CR4_PCIDE) - kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu); + kvm_mmu_unload(vcpu); else if ((cr4 ^ old_cr4) & X86_CR4_PGE) kvm_make_request(KVM_REQ_TLB_FLUSH_GUEST, vcpu); } -- 2.34.1.400.ga245620fadb-goog