From patchwork Thu Feb 11 15:02:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 12083527 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=-19.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, 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 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 F19B3C433E9 for ; Thu, 11 Feb 2021 15:23:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C229B64F11 for ; Thu, 11 Feb 2021 15:23:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230355AbhBKPXJ (ORCPT ); Thu, 11 Feb 2021 10:23:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:52624 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230333AbhBKPUh (ORCPT ); Thu, 11 Feb 2021 10:20:37 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5151464F2E; Thu, 11 Feb 2021 15:07:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1613056020; bh=MftR7VMP18psrqPKCYg64fQdJg2Q5xCCr+TeihrSvm0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c8gw9etrzq5oQ1oE5KKkNGzZzvF07HcMHGF9naYJt2Rg2shZLeT/5hyGbxK54OnvD AyxvSWO+xx9XH2AAncqEGlPYjNAgvQO0EaPUb203XBicVdJGgKYwdMH3/JR25Sae2r UYXHNh15+HQYyMg1o/sy4Dled8gDT6R45V7FBcT0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Paolo Bonzini , Joerg Roedel , Tom Lendacky , Brijesh Singh , Sean Christopherson , x86@kernel.org, kvm@vger.kernel.org, Peter Gonda Subject: [PATCH 4.19 19/24] Fix unsynchronized access to sev members through svm_register_enc_region Date: Thu, 11 Feb 2021 16:02:53 +0100 Message-Id: <20210211150148.593771643@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210211150147.743660073@linuxfoundation.org> References: <20210211150147.743660073@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Peter Gonda commit 19a23da53932bc8011220bd8c410cb76012de004 upstream. Grab kvm->lock before pinning memory when registering an encrypted region; sev_pin_memory() relies on kvm->lock being held to ensure correctness when checking and updating the number of pinned pages. Add a lockdep assertion to help prevent future regressions. 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: 1e80fdc09d12 ("KVM: SVM: Pin guest memory when SEV is active") Signed-off-by: Peter Gonda V2 - Fix up patch description - Correct file paths svm.c -> sev.c - Add unlock of kvm->lock on sev_pin_memory error V1 - https://lore.kernel.org/kvm/20210126185431.1824530-1-pgonda@google.com/ Message-Id: <20210127161524.2832400-1-pgonda@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/svm.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1832,6 +1832,8 @@ static struct page **sev_pin_memory(stru struct page **pages; unsigned long first, last; + lockdep_assert_held(&kvm->lock); + if (ulen == 0 || uaddr + ulen < uaddr) return NULL; @@ -7084,12 +7086,21 @@ static int svm_register_enc_region(struc 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; + mutex_unlock(&kvm->lock); goto e_free; } + region->uaddr = range->addr; + region->size = range->size; + + mutex_lock(&kvm->lock); + 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 @@ -7098,13 +7109,6 @@ static int svm_register_enc_region(struc */ 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: