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 7A0D3C43332 for ; Tue, 26 Jan 2021 22:48:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5762E2065D for ; Tue, 26 Jan 2021 22:48:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730020AbhAZWqc (ORCPT ); Tue, 26 Jan 2021 17:46:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394998AbhAZSzY (ORCPT ); Tue, 26 Jan 2021 13:55:24 -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 F0896C061793 for ; Tue, 26 Jan 2021 10:54:43 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id s64so13862987yba.20 for ; Tue, 26 Jan 2021 10:54:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:message-id:mime-version:subject:from:to:cc; bh=9to2H1cFYXc/ftlNkKuCOfsyg9/5wBUz/ls+mCyWEZs=; b=prBxemVJehhr0+ZWWH2Ff2UiFP29igURLHodMPi/TM2u4RHYrY9xUrlIet1xwv1ERy 0yz92AuhxZF1kWnoy1Rm5s1k2zzxBPmbXGFrpj/Iq9TaOTkvbgWZj5SzZr4IbwG8MdDo 7Y2wBFrQHWU9rrzG6TzOlGp8dGCn9LO/hVTGFEb6AFyC0jwo/V4ErXjPFgN9/zPTGqyr +1+k12S61GWluYFqqQjq30p++UegS0gltsnBC6Aj0BQN7D2SCjqoEdXhRlpWojNUXg3W Ei5C1V208AABLK0nt+z56pwLNzeeKxvZGyluoh1pUIhE+7opFnXLSlJxJJ+p+wXePRWx zcZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:message-id:mime-version:subject:from :to:cc; bh=9to2H1cFYXc/ftlNkKuCOfsyg9/5wBUz/ls+mCyWEZs=; b=Eqp06j/2yjCNczI7eVcZ22joXetSHLSyXkvGq3S+5fd4tDDZ/t46l4ZeaoB0PVHKRs 2r+1Z4JhQHOpJxv9UXkDS+CLKvb16kDytTi0VpTTMcTTrFfJpngFm3AVAnRvKItTwr+v G/NpaYROG6SiKJq16XlFU2y+42xW1Eb+YQ4ZtTXsXAvXM2SSBpE0+HR0vBiWZw6jdlkr plDWT+lJR4iZrRh97wTHo8fDfsZ0/UNIjp2TlUutSTswubL0gCVFeNj5Bjing8N9s+0q f59aK3ODKfg+3ktKlZAdGBufE18sRBIfYDERsmbmS5+OzTgKtSUAmnWI2AsK1vs4bEWe Frug== X-Gm-Message-State: AOAM532l+Flk1xnp3ICX6jWXFG0hm5MSszUUbHXhcFlfRRjRkCk46HTU /JX2Xmlu6atWFBKx6/oeTLi6MNrUa7BELQ3cF6N4nlxERYgAcsk0C2qOIqtrsGL8Q5jx7gKxWqM 8Pm0dx2mCf2q4X+FLmNwt0jiVtsXg/tw1euXcoTdp65Nyr+/AQfnxgoM1cg== X-Google-Smtp-Source: ABdhPJzDEQyw5qWF7Q4CXz78wHuuKbrWi6ACFbxCOYGxyVmyE0CnwCycuL3z1GtTxNOM8sB4xSdS9OC6s+k= Sender: "pgonda via sendgmr" X-Received: from pgonda1.kir.corp.google.com ([2620:0:1008:11:f693:9fff:fef4:e3a2]) (user=pgonda job=sendgmr) by 2002:a25:2351:: with SMTP id j78mr10191650ybj.495.1611687283114; Tue, 26 Jan 2021 10:54:43 -0800 (PST) Date: Tue, 26 Jan 2021 10:54:30 -0800 Message-Id: <20210126185431.1824530-1-pgonda@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.30.0.280.ga3ce27912f-goog Subject: [PATCH] Fix unsynchronized access to sev members through svm_register_enc_region From: Peter Gonda To: kvm@vger.kernel.org Cc: Peter Gonda , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Paolo Bonzini , Joerg Roedel , Tom Lendacky , Brijesh Singh , Sean Christopherson , x86@kernel.org, stable@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org sev_pin_memory assumes that callers hold the kvm->lock. This was true for all callers except svm_register_enc_region since it does not originate from svm_mem_enc_op. Also added lockdep annotation to help prevent future regressions. Tested: Booted SEV enabled VM on host. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Paolo Bonzini Cc: Joerg Roedel Cc: Tom Lendacky Cc: Brijesh Singh Cc: Sean Christopherson Cc: x86@kernel.org Cc: kvm@vger.kernel.org Cc: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org Fixes: 116a2214c5173 (KVM: SVM: Pin guest memory when SEV is active) Signed-off-by: Peter Gonda --- arch/x86/kvm/svm.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index afdc5b44fe9f..9884e57f3d0f 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1699,6 +1699,8 @@ static struct page **sev_pin_memory(struct kvm *kvm, unsigned long uaddr, struct page **pages; unsigned long first, last; + lockdep_assert_held(&kvm->lock); + if (ulen == 0 || uaddr + ulen < uaddr) return NULL; @@ -7228,12 +7230,19 @@ static int svm_register_enc_region(struct kvm *kvm, if (!region) return -ENOMEM; + mutex_lock(&kvm->lock); region->pages = sev_pin_memory(kvm, range->addr, range->size, ®ion->npages, 1); if (!region->pages) { ret = -ENOMEM; goto e_free; } + region->uaddr = range->addr; + region->size = range->size; + + list_add_tail(®ion->list, &sev->regions_list); + mutex_unlock(&kvm->lock); + /* * The guest may change the memory encryption attribute from C=0 -> C=1 * or vice versa for this memory range. Lets make sure caches are @@ -7242,13 +7251,6 @@ static int svm_register_enc_region(struct kvm *kvm, */ sev_clflush_pages(region->pages, region->npages); - region->uaddr = range->addr; - region->size = range->size; - - mutex_lock(&kvm->lock); - list_add_tail(®ion->list, &sev->regions_list); - mutex_unlock(&kvm->lock); - return ret; e_free: -- 2.30.0.280.ga3ce27912f-goog