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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1E48C4332F for ; Wed, 8 Dec 2021 16:54:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237392AbhLHQ5x (ORCPT ); Wed, 8 Dec 2021 11:57:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47540 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237373AbhLHQ5w (ORCPT ); Wed, 8 Dec 2021 11:57:52 -0500 Received: from mail-pg1-x530.google.com (mail-pg1-x530.google.com [IPv6:2607:f8b0:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 82DFDC061746 for ; Wed, 8 Dec 2021 08:54:20 -0800 (PST) Received: by mail-pg1-x530.google.com with SMTP id m24so2546705pgn.7 for ; Wed, 08 Dec 2021 08:54:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=wDsVhbUZQwon98TZc0uQWii9L9HtueN7zt3xozWU+o0=; b=qjKkcDy2Vnd99F+FcvoO1bC64kXXPcSt3EJIU+wYN4wrB3WKm+GgpQkRK8vgG4EyIP yEmXVWLQikSBg2dl3KZBUVIO21pKCDAL5+UQcr/qWb8OA/qHpthYaB0XLGbQbVpSjdRd 1w8aSVUXoZ9N/w2CCkBzUFjOi21cIX7FhfwEcc+0AFCTNu+XCFz29xYyQDRNWEI0UeOq XqLrgs12InSPFGTplPogvsmGvPMtB2wrVCg2Jd9H4ieohL+3kkioqBbLXbluWuW/sHMJ 36Ex+MxfgiTF+1zUstFYEUZi+55M56v4UMTV4U8oV/cYOlOYYOW5nQz9JbJICVp6wGII Wylg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=wDsVhbUZQwon98TZc0uQWii9L9HtueN7zt3xozWU+o0=; b=68Mn1QSs6c0YTLu1z5Or920RwQxD12knR8S7LvPI2G4RBaxjo/YvHp9/Ox3aM52KLo 0GV6Q0kXJ1aUntBuy1beX5gi3yHDUC9gJtpuOPusN07q6Tg2GpvqLwtwnjifP00naoxW pl3aYXL91B+YsKNLxHg4UOuwtw8Gy+5nrvO7zr7p9Kbd8gFEObLsvWHFCYojyRsrhPHn tSsEVyAoAnr1ocOhPhGOyU62dkrDyuxdCgP9Vcb4vIiAt3aNeXxFLfkhLYyxaEDRXMb7 r+5xGfEsh9TKGkKBq6Vi0OlSMg0Xal+HR1Mb9l654urfD6j/Yr8Qniqic9x0yinWB1hp R3SA== X-Gm-Message-State: AOAM531d2LFExOA8Ijzd1mU8lreOHgixqezcE41RGHGkzO5odvLqrnXy 9bhvgwC/OWxWoItaYy890T+njg== X-Google-Smtp-Source: ABdhPJxE3wYM+bIKVuUEjBr3ldRIzan4Rc3pmkStEhIojWk4Ag4lA1gCH7zbcEfstO/sqqo2+3iiiA== X-Received: by 2002:a05:6a00:a14:b0:4a0:945:16fa with SMTP id p20-20020a056a000a1400b004a0094516famr6527927pfh.9.1638982459816; Wed, 08 Dec 2021 08:54:19 -0800 (PST) Received: from google.com (157.214.185.35.bc.googleusercontent.com. [35.185.214.157]) by smtp.gmail.com with ESMTPSA id f3sm3090411pgv.51.2021.12.08.08.54.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 08 Dec 2021 08:54:19 -0800 (PST) Date: Wed, 8 Dec 2021 16:54:15 +0000 From: Sean Christopherson To: Paolo Bonzini Cc: Joao Martins , Maxim Levitsky , stable@vger.kernel.org, David Matlack , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH] selftests: KVM: avoid failures due to reserved HyperTransport region Message-ID: References: <20210805105423.412878-1-pbonzini@redhat.com> <4b530fb6-81cc-be36-aa68-92ec01c65775@oracle.com> <5f3c13be-f65d-1793-bd91-7491d3e149b0@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 09, 2021, Paolo Bonzini wrote: > So this HyperTransport region is not related to this issue, but the errata > does point out that FFFD_0000_0000h and upwards is special in guests. > > The Xen folks also had to deal with it only a couple months ago > (https://yhbt.net/lore/all/1eb16baa-6b1b-3b18-c712-4459bd83e1aa@citrix.com/): > > From "Open-Source Register Reference for AMD Family 17h Processors (PUB)": > https://developer.amd.com/wp-content/resources/56255_3_03.PDF > > "The processor defines a reserved memory address region starting at > FFFD_0000_0000h and extending up to FFFF_FFFF_FFFFh." > > It's still doesn't say that it's at the top of physical address space > although I understand that's how it's now implemented. The official > document doesn't confirm it will move along with physical address space > extension. > > [...] > > 1) On parts with <40 bits, its fully hidden from software > 2) Before Fam17h, it was always 12G just below 1T, even if there was > more RAM above this location > 3) On Fam17h and later, it is variable based on SME, and is either > just below 2^48 (no encryption) or 2^43 (encryption) > > > It's interesting that fn8000_000A EDX[28] is part of the reserved bits from > > that CPUID leaf. > > It's only been defined after AMD deemed that the errata was not fixable in > current generation processors); it's X86_FEATURE_SVME_ADDR_CHK now. > > I'll update the patch based on the findings from the Xen team. So, about that update... :-)