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 X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A022C433E0 for ; Fri, 22 Jan 2021 23:55:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5EAA823B51 for ; Fri, 22 Jan 2021 23:55:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726308AbhAVXyp (ORCPT ); Fri, 22 Jan 2021 18:54:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60832 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726448AbhAVXwd (ORCPT ); Fri, 22 Jan 2021 18:52:33 -0500 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3005CC0617AA for ; Fri, 22 Jan 2021 15:51:06 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id 67so7094656ybh.22 for ; Fri, 22 Jan 2021 15:51:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:reply-to:date:in-reply-to:message-id:mime-version:references :subject:from:to:cc; bh=r3IIkGAa61MnJqRj3fcRniDrryvcAMIqBhLKyFl38rA=; b=i/kBaLgRBYVZ0ZgLV1J9cHLj/jJy/sxK/Mg1oV7j4zoRI5zRWYtXPmiKSIl6uEEU7+ Bb2JpBuQ9PzOHY3f0nE1SQsK5SR9MoMEgXs9KjGVoNZS7Hy1zjxzzrarFPA3vAyueNuM 5I5IKEjLBOzrvwGtcSACwoU5rb48kKCzWuTnjyt00FfNCoo7nY2APFvJj3sdTIc7rRgQ 1Y/409GkeshmRujBFBV4eGq2tD2nJUJ+3NQmpNFJfl6m8F23ZEnjDZZp3MM1LJl7DHeJ hQqMrRvq9OLwHUtDKRoHCYb2fqQ3IrGAuuQZlo0uk2t4wR4P11Va8TAv7Q12+a9NYluW B3zw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:reply-to:date:in-reply-to:message-id :mime-version:references:subject:from:to:cc; bh=r3IIkGAa61MnJqRj3fcRniDrryvcAMIqBhLKyFl38rA=; b=NEEwBOlULzO21znpItoQ/7XIxao/fIUfLQT54kKdOw4nWT9cKDm+W9XrCiG43PXRyK GWxsgNY5/0m/+iZ/cvSTgO2VuoIrUxXiCOBhuoxa82PYLqXrux7a/gVTA45WN9gtvjsW +Gd0nPgJuqHihkWixs6hMmpFfDCSCNWxl5OGQr0HCMGLANuA4u3KXJZ8f2RA76oSk1J4 Vx8tpFr5NObv6ddeK6PUlbZmY9QJOdNbG+wjn+w2oRbwOHob29Ek3Z9/SJwrfREQvC4A bnOcv1BUA9OCZygf2kBct4VgWG6VisOWI73Tnjt25LJfAaMJCTNOwCkkUzpA1ZT3DlB/ W5qA== X-Gm-Message-State: AOAM531pBfJ6u48zwMjCIfnnd1rQnrCz3pN8QnK5/U91u/Oyeo6sEkyK QmPXcjwR471SyrnS299QQ8niK3KY6Ps= X-Google-Smtp-Source: ABdhPJz3mmxzI6jTLrn733eHumARphbHgVa0LiQzSZwODrHcFjN+KjRnng59m2ZkbGYrFf7QPWspkCybedU= Sender: "seanjc via sendgmr" X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:f:10:1ea0:b8ff:fe73:50f5]) (user=seanjc job=sendgmr) by 2002:a25:d70a:: with SMTP id o10mr9412902ybg.235.1611359465355; Fri, 22 Jan 2021 15:51:05 -0800 (PST) Reply-To: Sean Christopherson Date: Fri, 22 Jan 2021 15:50:49 -0800 In-Reply-To: <20210122235049.3107620-1-seanjc@google.com> Message-Id: <20210122235049.3107620-4-seanjc@google.com> Mime-Version: 1.0 References: <20210122235049.3107620-1-seanjc@google.com> X-Mailer: git-send-email 2.30.0.280.ga3ce27912f-goog Subject: [PATCH 3/3] KVM: SVM: Sync GPRs to the GHCB only after VMGEXIT 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, Brijesh Singh , Tom Lendacky Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sync GPRs to the GHCB on VMRUN only if a sync is needed, i.e. if the previous exit was a VMGEXIT and the guest is expecting some data back. Cc: Brijesh Singh Cc: Tom Lendacky Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/sev.c | 15 ++++++++++----- arch/x86/kvm/svm/svm.h | 1 + 2 files changed, 11 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index ac652bc476ae..9bd1e1650eb3 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -1418,10 +1418,13 @@ static void sev_es_sync_to_ghcb(struct vcpu_svm *svm) * Copy their values, even if they may not have been written during the * VM-Exit. It's the guest's responsibility to not consume random data. */ - ghcb_set_rax(ghcb, vcpu->arch.regs[VCPU_REGS_RAX]); - ghcb_set_rbx(ghcb, vcpu->arch.regs[VCPU_REGS_RBX]); - ghcb_set_rcx(ghcb, vcpu->arch.regs[VCPU_REGS_RCX]); - ghcb_set_rdx(ghcb, vcpu->arch.regs[VCPU_REGS_RDX]); + if (svm->need_sync_to_ghcb) { + ghcb_set_rax(ghcb, vcpu->arch.regs[VCPU_REGS_RAX]); + ghcb_set_rbx(ghcb, vcpu->arch.regs[VCPU_REGS_RBX]); + ghcb_set_rcx(ghcb, vcpu->arch.regs[VCPU_REGS_RCX]); + ghcb_set_rdx(ghcb, vcpu->arch.regs[VCPU_REGS_RDX]); + svm->need_sync_to_ghcb = false; + } } static void sev_es_sync_from_ghcb(struct vcpu_svm *svm) @@ -1441,8 +1444,10 @@ static void sev_es_sync_from_ghcb(struct vcpu_svm *svm) * VMMCALL allows the guest to provide extra registers. KVM also * expects RSI for hypercalls, so include that, too. * - * Copy their values to the appropriate location if supplied. + * Copy their values to the appropriate location if supplied, and + * flag that a sync back to the GHCB is needed on the next VMRUN. */ + svm->need_sync_to_ghcb = true; memset(vcpu->arch.regs, 0, sizeof(vcpu->arch.regs)); vcpu->arch.regs[VCPU_REGS_RAX] = ghcb_get_rax_if_valid(ghcb); diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 0fe874ae5498..4e2e5f9fbfc2 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -192,6 +192,7 @@ struct vcpu_svm { u64 ghcb_sa_len; bool ghcb_sa_sync; bool ghcb_sa_free; + bool need_sync_to_ghcb; }; struct svm_cpu_data { -- 2.30.0.280.ga3ce27912f-goog