From patchwork Fri Jan 22 20:21:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 12040427 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, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham 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 4A473C43381 for ; Fri, 22 Jan 2021 20:29:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 209B223AFC for ; Fri, 22 Jan 2021 20:29:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731034AbhAVU2f (ORCPT ); Fri, 22 Jan 2021 15:28:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729776AbhAVU0G (ORCPT ); Fri, 22 Jan 2021 15:26:06 -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 7F82FC0611C0 for ; Fri, 22 Jan 2021 12:22:24 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id l10so6660669ybt.6 for ; Fri, 22 Jan 2021 12:22:24 -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=ehdULWTO7EegFXRAR9N52T5SfWTOsL20pH6ob+5mEtA=; b=ncns3vkljJeRg+++B9bI09LSTPIN7Q50r6Q7c3MG3mj6tTLQaNCbLE7wM8xKTNclNM Xb7K5tzwyTXa4bffG5EKhNkSaXz30tPX9tCoPNbuQ/hMkGdSr7CfpXYWs+efUuAj8cfh fqpXgp5EaS838qONnFeoLOuKl6380AywdBxmcehdaKJkRWwU3iRgBx0O3QwZPFFGP3no j0Ws4IvPqfGHisE28k+OQm6EgqgwuOp1shbTTLVEVzv7c9UGmdqyzY8s9SL+fidtXZyj PFM6jOmCk5X32S6qiHLRJP5DqpHQY5Fil30Nvx3NUdObX4SZL+37j5IqYdVW2VLqTVWF y1zg== 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=ehdULWTO7EegFXRAR9N52T5SfWTOsL20pH6ob+5mEtA=; b=CkhvSqgQKJv0y0y9D2mdGXN+lZZ2NRMHNXQ3j2u8hk/m5MuhULgU8NxuKvcsJ2Ml7x yWznDXaVvz7wVbRXYfUZS/7u5YipE+cZ+dzM5LnoUDKjkDUx9EtBBAjVN/y6Ew8P9RHh E9BZpaq/RWBH2da3J/FrHjoN3X07xWTqTZSUYfbPZAfOICrmnaj5kHK1/g5vqVKVMghu vCYfztzW0wq4YPdUlsLu0zegrNGtCfBUUNqBp4QMZHkhDaiW7sm6KOTkuVKNP9xSe/G3 73TqvQGNkDMabCflNnuqVZpADk1jgsWjtdecwZrF2XqAwbpZpv/tljyDSmki8yq4htRa S0yg== X-Gm-Message-State: AOAM531UP7icn0m2oFcr5g3nXjrDNSfm+s2u3C06sFncAo/cWlbp4teu xp6HvY+c0bMNWTFCidgiGdx2G6x3pgA= X-Google-Smtp-Source: ABdhPJzLhnyCrRs/Bk9YHCsNQ28pCnNpi0SPWgybuUOEstJduRVYRC0Mk+Qb4Qf5/pmV72gNAwVxTE51u/Y= 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:db87:: with SMTP id g129mr3270161ybf.518.1611346943739; Fri, 22 Jan 2021 12:22:23 -0800 (PST) Reply-To: Sean Christopherson Date: Fri, 22 Jan 2021 12:21:44 -0800 In-Reply-To: <20210122202144.2756381-1-seanjc@google.com> Message-Id: <20210122202144.2756381-14-seanjc@google.com> Mime-Version: 1.0 References: <20210122202144.2756381-1-seanjc@google.com> X-Mailer: git-send-email 2.30.0.280.ga3ce27912f-goog Subject: [PATCH v3 13/13] KVM: SVM: Skip SEV cache flush if no ASIDs have been used From: Sean Christopherson To: Paolo Bonzini , Dave Hansen , Andy Lutomirski , Peter Zijlstra Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Borislav Petkov , Tom Lendacky , Brijesh Singh Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Skip SEV's expensive WBINVD and DF_FLUSH if there are no SEV ASIDs waiting to be reclaimed, e.g. if SEV was never used. This "fixes" an issue where the DF_FLUSH fails during hardware teardown if the original SEV_INIT failed. Ideally, SEV wouldn't be marked as enabled in KVM if SEV_INIT fails, but that's a problem for another day. Signed-off-by: Sean Christopherson Reviewed-by: Tom Lendacky --- arch/x86/kvm/svm/sev.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 73da2af1e25d..0a4715e60b88 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -56,9 +56,14 @@ struct enc_region { unsigned long size; }; -static int sev_flush_asids(void) +static int sev_flush_asids(int min_asid, int max_asid) { - int ret, error = 0; + int ret, pos, error = 0; + + /* Check if there are any ASIDs to reclaim before performing a flush */ + pos = find_next_bit(sev_reclaim_asid_bitmap, max_sev_asid, min_asid); + if (pos >= max_asid) + return -EBUSY; /* * DEACTIVATE will clear the WBINVD indicator causing DF_FLUSH to fail, @@ -80,14 +85,7 @@ static int sev_flush_asids(void) /* Must be called with the sev_bitmap_lock held */ static bool __sev_recycle_asids(int min_asid, int max_asid) { - int pos; - - /* Check if there are any ASIDs to reclaim before performing a flush */ - pos = find_next_bit(sev_reclaim_asid_bitmap, max_sev_asid, min_asid); - if (pos >= max_asid) - return false; - - if (sev_flush_asids()) + if (sev_flush_asids(min_asid, max_asid)) return false; /* The flush process will flush all reclaimable SEV and SEV-ES ASIDs */ @@ -1324,10 +1322,11 @@ void sev_hardware_teardown(void) if (!sev_enabled) return; + /* No need to take sev_bitmap_lock, all VMs have been destroyed. */ + sev_flush_asids(0, max_sev_asid); + bitmap_free(sev_asid_bitmap); bitmap_free(sev_reclaim_asid_bitmap); - - sev_flush_asids(); } int sev_cpu_init(struct svm_cpu_data *sd)