From patchwork Tue Mar 3 17:44:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 229972 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=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 417A4C3F2D7 for ; Tue, 3 Mar 2020 18:02:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1DAB320656 for ; Tue, 3 Mar 2020 18:02:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583258544; bh=qjzHJ7RyXbk68kqkDHkrRTeM8Wey8C0wgzXF/aGFSeE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=qn5x7uNUC2TGmVDw+xTt6gOmTkMifarEQM5Nmo9Voef+AMcE+rnrktYClp7zu7d6R m3AhNGlJlJI2vzkAMs13H8RKPsUqtE1uStXrZ6ffgWfh3XNOAxgXI7BPaK/V51UuxV fpH44u06uwpSGnrjihnIO7YmXWp8U6MlokdsCZSs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388177AbgCCSCX (ORCPT ); Tue, 3 Mar 2020 13:02:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:46910 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388192AbgCCSCW (ORCPT ); Tue, 3 Mar 2020 13:02:22 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 4075220866; Tue, 3 Mar 2020 18:02:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583258540; bh=qjzHJ7RyXbk68kqkDHkrRTeM8Wey8C0wgzXF/aGFSeE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wVTXD9ux069sZP4A4SaxVvcGIrF4+OXGoYzOn7lruVEe3WgDj3Lylxk9FOb7U2bkh OGMs+Tjq/lpHkoCOQcU0V34EsbRZj7qFTyqCcM826Sn2glnWj8BCaCW6tIl5a4NKyj KnkS0LC7M3AwCYB/OR2ejh/3qGWOZiTydG8XIc3U= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sean Christopherson , Tom Lendacky , Paolo Bonzini Subject: [PATCH 4.19 70/87] KVM: SVM: Override default MMIO mask if memory encryption is enabled Date: Tue, 3 Mar 2020 18:44:01 +0100 Message-Id: <20200303174356.572899901@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200303174349.075101355@linuxfoundation.org> References: <20200303174349.075101355@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Tom Lendacky commit 52918ed5fcf05d97d257f4131e19479da18f5d16 upstream. The KVM MMIO support uses bit 51 as the reserved bit to cause nested page faults when a guest performs MMIO. The AMD memory encryption support uses a CPUID function to define the encryption bit position. Given this, it is possible that these bits can conflict. Use svm_hardware_setup() to override the MMIO mask if memory encryption support is enabled. Various checks are performed to ensure that the mask is properly defined and rsvd_bits() is used to generate the new mask (as was done prior to the change that necessitated this patch). Fixes: 28a1f3ac1d0c ("kvm: x86: Set highest physical address bits in non-present/reserved SPTEs") Suggested-by: Sean Christopherson Reviewed-by: Sean Christopherson Signed-off-by: Tom Lendacky Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/svm.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1298,6 +1298,47 @@ static void shrink_ple_window(struct kvm control->pause_filter_count, old); } +/* + * The default MMIO mask is a single bit (excluding the present bit), + * which could conflict with the memory encryption bit. Check for + * memory encryption support and override the default MMIO mask if + * memory encryption is enabled. + */ +static __init void svm_adjust_mmio_mask(void) +{ + unsigned int enc_bit, mask_bit; + u64 msr, mask; + + /* If there is no memory encryption support, use existing mask */ + if (cpuid_eax(0x80000000) < 0x8000001f) + return; + + /* If memory encryption is not enabled, use existing mask */ + rdmsrl(MSR_K8_SYSCFG, msr); + if (!(msr & MSR_K8_SYSCFG_MEM_ENCRYPT)) + return; + + enc_bit = cpuid_ebx(0x8000001f) & 0x3f; + mask_bit = boot_cpu_data.x86_phys_bits; + + /* Increment the mask bit if it is the same as the encryption bit */ + if (enc_bit == mask_bit) + mask_bit++; + + /* + * If the mask bit location is below 52, then some bits above the + * physical addressing limit will always be reserved, so use the + * rsvd_bits() function to generate the mask. This mask, along with + * the present bit, will be used to generate a page fault with + * PFER.RSV = 1. + * + * If the mask bit location is 52 (or above), then clear the mask. + */ + mask = (mask_bit < 52) ? rsvd_bits(mask_bit, 51) | PT_PRESENT_MASK : 0; + + kvm_mmu_set_mmio_spte_mask(mask, PT_WRITABLE_MASK | PT_USER_MASK); +} + static __init int svm_hardware_setup(void) { int cpu; @@ -1352,6 +1393,8 @@ static __init int svm_hardware_setup(voi } } + svm_adjust_mmio_mask(); + for_each_possible_cpu(cpu) { r = svm_cpu_init(cpu); if (r)