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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 39E1AC352A4 for ; Mon, 10 Feb 2020 12:46:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 139242051A for ; Mon, 10 Feb 2020 12:46:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338795; bh=mvnVJV3p3/i8WhR2AKqQjf6C6rLK0nHmBp7089fRAX4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=IG+8DPBVe6KnoP6jZIdLc606GehdqkcOZKH58oBiQiVgPbiwOmA7BkMLVnOZIy36B Z2EWy+5JiX3fn9JfwW+sNlHvqSfkBAlETIg+GtHNaL3C15AYYTPtgzhKhOslgMlLLz gKXPYRAsCXwngmTQlQXPoEACs2JiAPmR++gcT6V8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730615AbgBJMqe (ORCPT ); Mon, 10 Feb 2020 07:46:34 -0500 Received: from mail.kernel.org ([198.145.29.99]:44324 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730046AbgBJMll (ORCPT ); Mon, 10 Feb 2020 07:41:41 -0500 Received: from localhost (unknown [209.37.97.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9F6A820838; Mon, 10 Feb 2020 12:41:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338500; bh=mvnVJV3p3/i8WhR2AKqQjf6C6rLK0nHmBp7089fRAX4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hFp7nOFtPF+8ttiuEbxE9M4YPX9NnABkfHV498Vpo6/SNdL4bWcS99/xI+pT+tkVJ Krjfsu1nKt4wtG5hC0C99X1+7ER6206lkHghgIwqLXAmcOZPilH6Q4QHgf7Ljerft/ yeVpJ4LYSJY8UJQCBtw1t3TRVfQaszJDC+BHgTQ8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ben Gardon , Paolo Bonzini Subject: [PATCH 5.5 254/367] KVM: x86: fix overlap between SPTE_MMIO_MASK and generation Date: Mon, 10 Feb 2020 04:32:47 -0800 Message-Id: <20200210122447.865741331@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200210122423.695146547@linuxfoundation.org> References: <20200210122423.695146547@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Paolo Bonzini commit 56871d444bc4d7ea66708775e62e2e0926384dbc upstream. The SPTE_MMIO_MASK overlaps with the bits used to track MMIO generation number. A high enough generation number would overwrite the SPTE_SPECIAL_MASK region and cause the MMIO SPTE to be misinterpreted. Likewise, setting bits 52 and 53 would also cause an incorrect generation number to be read from the PTE, though this was partially mitigated by the (useless if it weren't for the bug) removal of SPTE_SPECIAL_MASK from the spte in get_mmio_spte_generation. Drop that removal, and replace it with a compile-time assertion. Fixes: 6eeb4ef049e7 ("KVM: x86: assign two bits to track SPTE kinds") Reported-by: Ben Gardon Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/mmu/mmu.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -418,22 +418,24 @@ static inline bool is_access_track_spte( * requires a full MMU zap). The flag is instead explicitly queried when * checking for MMIO spte cache hits. */ -#define MMIO_SPTE_GEN_MASK GENMASK_ULL(18, 0) +#define MMIO_SPTE_GEN_MASK GENMASK_ULL(17, 0) #define MMIO_SPTE_GEN_LOW_START 3 #define MMIO_SPTE_GEN_LOW_END 11 #define MMIO_SPTE_GEN_LOW_MASK GENMASK_ULL(MMIO_SPTE_GEN_LOW_END, \ MMIO_SPTE_GEN_LOW_START) -#define MMIO_SPTE_GEN_HIGH_START 52 -#define MMIO_SPTE_GEN_HIGH_END 61 +#define MMIO_SPTE_GEN_HIGH_START PT64_SECOND_AVAIL_BITS_SHIFT +#define MMIO_SPTE_GEN_HIGH_END 62 #define MMIO_SPTE_GEN_HIGH_MASK GENMASK_ULL(MMIO_SPTE_GEN_HIGH_END, \ MMIO_SPTE_GEN_HIGH_START) + static u64 generation_mmio_spte_mask(u64 gen) { u64 mask; WARN_ON(gen & ~MMIO_SPTE_GEN_MASK); + BUILD_BUG_ON((MMIO_SPTE_GEN_HIGH_MASK | MMIO_SPTE_GEN_LOW_MASK) & SPTE_SPECIAL_MASK); mask = (gen << MMIO_SPTE_GEN_LOW_START) & MMIO_SPTE_GEN_LOW_MASK; mask |= (gen << MMIO_SPTE_GEN_HIGH_START) & MMIO_SPTE_GEN_HIGH_MASK; @@ -444,8 +446,6 @@ static u64 get_mmio_spte_generation(u64 { u64 gen; - spte &= ~shadow_mmio_mask; - gen = (spte & MMIO_SPTE_GEN_LOW_MASK) >> MMIO_SPTE_GEN_LOW_START; gen |= (spte & MMIO_SPTE_GEN_HIGH_MASK) >> MMIO_SPTE_GEN_HIGH_START; return gen;