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X-IronPort-AV: E=McAfee;i="6500,9779,10636"; a="322714282" X-IronPort-AV: E=Sophos;i="5.98,225,1673942400"; d="scan'208";a="322714282" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Mar 2023 08:15:49 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10636"; a="817622794" X-IronPort-AV: E=Sophos;i="5.98,225,1673942400"; d="scan'208";a="817622794" Received: from asaha3-mobl1.amr.corp.intel.com (HELO [10.251.12.67]) ([10.251.12.67]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Mar 2023 08:15:47 -0800 Message-ID: <140c3675-376a-be37-56da-878b08df5507@intel.com> Date: Wed, 1 Mar 2023 08:15:46 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH RFC v8 15/56] x86/sev: Invalidate pages from the direct map when adding them to the RMP table Content-Language: en-US To: Michael Roth , kvm@vger.kernel.org Cc: linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-crypto@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, jroedel@suse.de, thomas.lendacky@amd.com, hpa@zytor.com, ardb@kernel.org, pbonzini@redhat.com, seanjc@google.com, vkuznets@redhat.com, jmattson@google.com, luto@kernel.org, dave.hansen@linux.intel.com, slp@redhat.com, pgonda@google.com, peterz@infradead.org, srinivas.pandruvada@linux.intel.com, rientjes@google.com, dovmurik@linux.ibm.com, tobin@ibm.com, bp@alien8.de, vbabka@suse.cz, kirill@shutemov.name, ak@linux.intel.com, tony.luck@intel.com, marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com, alpergun@google.com, dgilbert@redhat.com, jarkko@kernel.org, ashish.kalra@amd.com, nikunj.dadhania@amd.com, Brijesh Singh References: <20230220183847.59159-1-michael.roth@amd.com> <20230220183847.59159-16-michael.roth@amd.com> From: Dave Hansen In-Reply-To: <20230220183847.59159-16-michael.roth@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: cpoq8t7opmwkrijco4fo5y3i5jznd7cc X-Rspam-User: X-Rspamd-Queue-Id: BF7CD120021 X-Rspamd-Server: rspam06 X-HE-Tag: 1677687366-972970 X-HE-Meta: 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 buacGgHq vgtb3c3Hl+h1yiI3c6l71Lc3ejVU9LfBCsZ2VDy0P4O3TerB4kB+UXBOiXdWzM4hns59FoWTuiSzcEtutB55E4AWBpDRNVcZ+LAz1tqSWSdV7Wpij2Ls6NURrj4mKetv2KKRqX8KmUtvDmaKaNEkRHZNVZiiuKDadURf5jip0EZCyIxlrAick1ARcJw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2/20/23 10:38, Michael Roth wrote: > From: Brijesh Singh > > The integrity guarantee of SEV-SNP is enforced through the RMP table. > The RMP is used with standard x86 and IOMMU page tables to enforce > memory restrictions and page access rights. The RMP check is enforced as > soon as SEV-SNP is enabled globally in the system. When hardware > encounters an RMP-check failure, it raises a page-fault exception. > > The rmp_make_private() and rmp_make_shared() helpers are used to add > or remove the pages from the RMP table. Improve the rmp_make_private() > to invalidate state so that pages cannot be used in the direct-map after > they are added the RMP table, and restored to their default valid > permission after the pages are removed from the RMP table. This is a purely "what" changelog. It doesn't explain the "why" at all. Could you please elaborate on why this unmapping operation is necessary?