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Wed, 17 Jan 2024 09:34:05 +0000 (UTC) Date: Wed, 17 Jan 2024 10:34:00 +0100 From: Borislav Petkov To: Dave Hansen Cc: Michael Roth , x86@kernel.org, kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-crypto@vger.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, tobin@ibm.com, vbabka@suse.cz, kirill@shutemov.name, ak@linux.intel.com, tony.luck@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, alpergun@google.com, jarkko@kernel.org, ashish.kalra@amd.com, nikunj.dadhania@amd.com, pankaj.gupta@amd.com, liam.merwick@oracle.com Subject: Re: [PATCH v1 11/26] x86/sev: Invalidate pages from the direct map when adding them to the RMP table Message-ID: <20240117093341.GBZaee9f614RSBhXi0@fat_crate.local> References: <20231230161954.569267-1-michael.roth@amd.com> <20231230161954.569267-12-michael.roth@amd.com> <20240115090948.GBZaT2XKw00PokD-WJ@fat_crate.local> <6ecc4517-9a4f-4d7e-a630-2b8357b7be05@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <6ecc4517-9a4f-4d7e-a630-2b8357b7be05@intel.com> X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: B1B3B4000C X-Stat-Signature: o9p6o1kw1r4psoqmxxe6wgka7jsuxwjh X-HE-Tag: 1705484089-449253 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000007, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Jan 16, 2024 at 08:21:09AM -0800, Dave Hansen wrote: > The problem will be the first time someone sees a regression when their > direct-map-fracturing kernel feature (secret pages, SNP host, etc...) > collides with some workload that's sensitive to kernel TLB pressure. Yeah, and that "workload" will be some microbenchmark crap which people would pay too much attention to, without it having any relevance to real-world scenarios. Completely hypothetically speaking, ofc. :-) -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette