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Received: from SN6PR12MB2767.namprd12.prod.outlook.com (2603:10b6:805:75::23) by DS0PR12MB6608.namprd12.prod.outlook.com (2603:10b6:8:d0::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5834.15; Tue, 22 Nov 2022 10:32:24 +0000 Received: from SN6PR12MB2767.namprd12.prod.outlook.com ([fe80::395:21e6:abfd:7894]) by SN6PR12MB2767.namprd12.prod.outlook.com ([fe80::395:21e6:abfd:7894%6]) with mapi id 15.20.5834.015; Tue, 22 Nov 2022 10:32:24 +0000 Message-ID: Date: Tue, 22 Nov 2022 04:32:18 -0600 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.2.1 Subject: Re: [PATCH Part2 v6 14/49] crypto: ccp: Handle the legacy TMR allocation when SNP is enabled Content-Language: en-US To: Borislav Petkov Cc: x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-crypto@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, michael.roth@amd.com, 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 References: <3a51840f6a80c87b39632dc728dbd9b5dd444cd7.1655761627.git.ashish.kalra@amd.com> <380c9748-1c86-4763-ea18-b884280a3b60@amd.com> From: "Kalra, Ashish" In-Reply-To: Content-Type: text/plain; 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Not sure about panic considering this should almost never happen > and a warning would allow for people to catch dumps and debug the issue. > > * firmware error: I don't think you can know that that is really > the case on a production system without additional fw debugging > capabilities. Dumping a warning would be the least we can do here too, > to signal that something's out of the ordinary and so people can look > into it further. Please note that in both cases, these non-reclaimed pages cannot be freed/returned back to the page allocator. Anytime the kernel accesses these pages it will cause a panic or host process crash. So along with warning, the pages will be added to a leaked pages list, but there is no poisoning or anything, only need to ensure that these pages are not touched/accessed again. Thanks, Ashish > > So yeah, a big fat warning is a good start. And then you don't need any > memory poisoning etc gunk. >