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X-IronPort-AV: E=McAfee;i="6500,9779,10636"; a="314881609" X-IronPort-AV: E=Sophos;i="5.98,225,1673942400"; d="scan'208";a="314881609" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Mar 2023 08:56:08 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10636"; a="738700170" X-IronPort-AV: E=Sophos;i="5.98,225,1673942400"; d="scan'208";a="738700170" Received: from asaha3-mobl1.amr.corp.intel.com (HELO [10.251.12.67]) ([10.251.12.67]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Mar 2023 08:56:06 -0800 Message-ID: Date: Wed, 1 Mar 2023 08:56:05 -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 00/56] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support 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 References: <20230220183847.59159-1-michael.roth@amd.com> From: Dave Hansen In-Reply-To: <20230220183847.59159-1-michael.roth@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 5748920023 X-Stat-Signature: m37fcoorbp79rz5ep7s336wa6dtrjthf X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1677689779-325810 X-HE-Meta: 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 pd1XtTwk MVkV7umI5EeNgCBwomgj5XTtGnVC98kNA9gS+4u3EPWVo6zC80VvtzmFnTHWgPg3LfT7JFDkQ6KPlYkmJceMQ510kBKPKlGf0UsL2vrvPGvZHiulYxppk/RFuuNyeYLgdIe60w/bzRKb0UuR4hbCCGREHAbKPC8DdO6jl 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 10:37, Michael Roth wrote: > The RMP check is enforced as soon as SEV-SNP is enabled. Not every memory > access requires an RMP check. In particular, the read accesses from the > hypervisor do not require RMP checks because the data confidentiality is > already protected via memory encryption. When hardware encounters an RMP > checks failure, it raises a page-fault exception. If RMP check failure > is due to the page-size mismatch, then split the large page to resolve > the fault. What does this all _mean_? When does the kernel need to care about a "page-size mismatch"?