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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 38DE1C43603 for ; Wed, 4 Dec 2019 15:40:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0969220833 for ; Wed, 4 Dec 2019 15:40:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="LkEmcI4T" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728580AbfLDPkt (ORCPT ); Wed, 4 Dec 2019 10:40:49 -0500 Received: from mail-wr1-f68.google.com ([209.85.221.68]:42430 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728357AbfLDPkl (ORCPT ); Wed, 4 Dec 2019 10:40:41 -0500 Received: by mail-wr1-f68.google.com with SMTP id a15so9144050wrf.9; Wed, 04 Dec 2019 07:40:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id; bh=3CWC98h+5raJqQO+ka9hGiDloggJe6dDITvR1rS981E=; b=LkEmcI4TGNSbygcJ7Cko+s9jE4BlWzkAAeKiWUTHaBfr1yAo7wjnpKwN1v9UuMx65t pVyFemQvkAQP4sTma62IrTHQJ7WI6CHPm+t8RcqfXnJ+Edn+3dAu6Ay138Uq+Nd+BG8W 7F+vqfv2mPGubnmF3tOpfnqMAxKjleNr67b4Y2neErbm/mGF4i4RitGjxfgNhn/cZOIL zKT/Uk9ijI5xzkpnLzA0o6iXP0ECKT4myNr9sII/seqoKUdblE2IyonZ8c1j72peaK5I RB6Ih+LIi+kJiwXcwP4pgSCroZKNZGxPGP6yU8fAj0vW54DCYUInhLM7NL1c3eEfJZEe SXvA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id; bh=3CWC98h+5raJqQO+ka9hGiDloggJe6dDITvR1rS981E=; b=G71MsSE1Kf4zhZRgrYj1D5afo77NuagSHrufcg+dxhsVt4IQBlpmclsMQCvsR+/sbn nLE3vxtDdgaHzuOmfnhgBV1lafXTygDXPoTsPo8hB6xa4uOxr3T4N67moT48MczYi0SL 8E1ii1MZrAyApvLfYIXHd5Wxe2i9yVc0+5+F7yos48aQ+BGcKx9aFk2BmnTwdngF2v5L BIfUljgtGr2Ij413xipgasS9OEySMNH3RL+grbg14lrsQJJhdg1M07dgN2Xa5DCpFlOb Gd3kpgtpm/AEnPxDM192h5FI5erqBZN+LgSuDS2ix3dCTrgn9RGKUxtEe1Dt7i56Asae Ubpg== X-Gm-Message-State: APjAAAV4b7fkitg52YnUMkMRaLEGBW8/gMyhcMu13XWXmua8RMM7AM1H c97RwdYhUKjmK88oRSLxENnm2brc X-Google-Smtp-Source: APXvYqzZo5rJU83WbGx4l8YKrQdA+4qX4BShmaAoOAj76qDv2/BdhY3tSWVbfAfWwkcKl922ZsNHhQ== X-Received: by 2002:adf:dd52:: with SMTP id u18mr4805400wrm.131.1575474038983; Wed, 04 Dec 2019 07:40:38 -0800 (PST) Received: from 640k.lan ([93.56.166.5]) by smtp.gmail.com with ESMTPSA id d19sm2372235wmd.38.2019.12.04.07.40.38 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 04 Dec 2019 07:40:38 -0800 (PST) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: thomas.lendacky@amd.com, sean.j.christopherson@intel.com, stable@vger.kernel.org Subject: [PATCH v2] KVM: x86: use CPUID to locate host page table reserved bits Date: Wed, 4 Dec 2019 16:40:37 +0100 Message-Id: <1575474037-7903-1-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.8.3.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The comment in kvm_get_shadow_phys_bits refers to MKTME, but the same is actually true of SME and SEV. Just use CPUID[0x8000_0008].EAX[7:0] unconditionally if available, it is simplest and works even if memory is not encrypted. Cc: stable@vger.kernel.org Reported-by: Tom Lendacky Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu/mmu.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 6f92b40d798c..1e4ee4f8de5f 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -538,16 +538,20 @@ void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask, static u8 kvm_get_shadow_phys_bits(void) { /* - * boot_cpu_data.x86_phys_bits is reduced when MKTME is detected - * in CPU detection code, but MKTME treats those reduced bits as - * 'keyID' thus they are not reserved bits. Therefore for MKTME - * we should still return physical address bits reported by CPUID. + * boot_cpu_data.x86_phys_bits is reduced when MKTME or SME are detected + * in CPU detection code, but the processor treats those reduced bits as + * 'keyID' thus they are not reserved bits. Therefore KVM needs to look at + * the physical address bits reported by CPUID. */ - if (!boot_cpu_has(X86_FEATURE_TME) || - WARN_ON_ONCE(boot_cpu_data.extended_cpuid_level < 0x80000008)) - return boot_cpu_data.x86_phys_bits; + if (likely(boot_cpu_data.extended_cpuid_level >= 0x80000008)) + return cpuid_eax(0x80000008) & 0xff; - return cpuid_eax(0x80000008) & 0xff; + /* + * Quite weird to have VMX or SVM but not MAXPHYADDR; probably a VM with + * custom CPUID. Proceed with whatever the kernel found since these features + * aren't virtualizable (SME/SEV also require CPUIDs higher than 0x80000008). + */ + return boot_cpu_data.x86_phys_bits; } static void kvm_mmu_reset_all_pte_masks(void) -- 1.8.3.1