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Wed, 20 Mar 2024 12:19:06 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.205]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0296140C6CB3; Wed, 20 Mar 2024 12:19:04 +0000 (UTC) Date: Wed, 20 Mar 2024 12:18:43 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Michael Roth Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, Tom Lendacky , Paolo Bonzini , Markus Armbruster , Pankaj Gupta , Xiaoyao Li , Isaku Yamahata Subject: Re: [PATCH v3 42/49] i386/sev: Add support for SNP CPUID validation Message-ID: References: <20240320083945.991426-1-michael.roth@amd.com> <20240320083945.991426-43-michael.roth@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240320083945.991426-43-michael.roth@amd.com> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.2 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.417, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Mar 20, 2024 at 03:39:38AM -0500, Michael Roth wrote: > SEV-SNP firmware allows a special guest page to be populated with a > table of guest CPUID values so that they can be validated through > firmware before being loaded into encrypted guest memory where they can > be used in place of hypervisor-provided values[1]. > > As part of SEV-SNP guest initialization, use this interface to validate > the CPUID entries reported by KVM_GET_CPUID2 prior to initial guest > start and populate the CPUID page reserved by OVMF with the resulting > encrypted data. > > [1] SEV SNP Firmware ABI Specification, Rev. 0.8, 8.13.2.6 > > Signed-off-by: Michael Roth > --- > target/i386/sev.c | 159 +++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 158 insertions(+), 1 deletion(-) > > +static void > +sev_snp_cpuid_report_mismatches(SnpCpuidInfo *old, > + SnpCpuidInfo *new) > +{ > + size_t i; > + > + if (old->count != new->count) { > + error_report("SEV-SNP: CPUID validation failed due to count mismatch, provided: %d, expected: %d", > + old->count, new->count); > + } Missing 'return' here, may result in array out of bounds on 'new->entries' in the next loop > + > + for (i = 0; i < old->count; i++) { > + SnpCpuidFunc *old_func, *new_func; > + > + old_func = &old->entries[i]; > + new_func = &new->entries[i]; > + > + if (memcmp(old_func, new_func, sizeof(SnpCpuidFunc))) { > + error_report("SEV-SNP: CPUID validation failed for function 0x%x, index: 0x%x.\n" > + "provided: eax:0x%08x, ebx: 0x%08x, ecx: 0x%08x, edx: 0x%08x\n" > + "expected: eax:0x%08x, ebx: 0x%08x, ecx: 0x%08x, edx: 0x%08x", > + old_func->eax_in, old_func->ecx_in, > + old_func->eax, old_func->ebx, old_func->ecx, old_func->edx, > + new_func->eax, new_func->ebx, new_func->ecx, new_func->edx); > + } > + } > +} > + With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|