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bh=mEIlsiCgiRPca7MIEp0cdGq/tH1/+rGW8cuwJMfMUf0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mCZxNJ8xqKIPIJ+QzzzJsJR394Fy8eD+SyWyhwuthJnpMbOqI03lzjQlKaZrPnhtS Ex1DArvhBsu807BjZBxNYrsfhTEwNm6gPc+An3kcRaLoEkMB6M19c4DMQj+b8KtvoC AAs1inzY1AJFjgVryP/yF34N+gMVaJfGmsqP5raUF0AICJPo8GNlmJr72nTldohUta 0sYmdo5g0HompG0016vu/uyg1CDUgQFGjKM7tgoYjIlbtY4C//M+9klpIcSf8bHC0f rZpiXp1bcEAcktV+pJeryrhe6rOAEcE9v748PNKLwKhLMS6tukBOdDyABD1ieJFwnO /fvcjwbaC5ogQ== Date: Fri, 30 Dec 2022 17:19:49 +0200 From: Mike Rapoport To: Borislav Petkov Cc: Michael Roth , Ashish Kalra , 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, 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 Subject: Re: [PATCH Part2 v6 07/49] x86/sev: Invalid pages from direct map when adding it to RMP table Message-ID: References: <243778c282cd55a554af9c11d2ecd3ff9ea6820f.1655761627.git.ashish.kalra@amd.com> <20221219150026.bltiyk72pmdc2ic3@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: BB40D4001A X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: wawir3sqypsbkifbs8ffpydxm4mrzni8 X-HE-Tag: 1672413616-460682 X-HE-Meta: U2FsdGVkX1933BookxCNgqNXEEc0Tm6w6uH+4PpB0HOnX4f5bHGGadjAoTIcT+2F01uIysiB/VDY1XtwP+Q2YgebAPvw+Iy0NpVbGhJAlzshGiyb9n5SMRrP4prcXLRoQl4zls34+zkzn452TYEwzdroNbkITrQi1oGCgyG4I/1RK3C/pyANuNXx1giiUkCq1aiGXa8L/VqsrBa0TS5itmYxHfwuipv+ScbjjouN0qsBDuBM2V1Sqq8jSiyaoBiqTfvocb9eZzzqCSRYC/yXOSFKEoAyY5VA5aBe77ZcGowd0ROPGie4vKLVmcF9VwevBTs0O6pU3jRfGivguhH28JoZLHr38bqrLZPSLMvpDPkKbgfInz7zW2TjK/MmM4BcKJfYY4j7udcqpYyWBl9mCScMYFu+YYfHJTZIVzqKUQybCNZdqer7cVGz7osDdvrtIgkZvXUnPckbIqlU3j8BiHv3mvr5PiI6N8Xhc8vhuJJylnV59s2mdG9NlRgvQHpA11RqrD9v0IABCK4tul3yXPJznffW25UZ19sI45uWLWOMzK7MNoJxToTWli5qj+9RSBwliXfbg1fVE0jpe1JQu5Q2SBxo3X6rCxGqbwX+XPWUlhLzVX1OU3blfIR5ou86dodihywtRS/qohIk9kjqgjpWs+asWcn/4LA3PfZR9aSVzQacj5jjitdGh2GLOu+tVosMuOcSpLUVv8GJbTKjHzvNZmeNqiaFgDLodoT2UHMCs2GHdQPlpyGKOkKTBI564QnyKPrHwNLsRvnmrQenQz5Tjx6fxRq1hoQ88z1BvLeRm2QyeHcFTXD0/wDt+QEaG8/AigdWZzoUELBrmXOJTXKmpB1+3N43l/9mjZGxeTbM63d78GHefKHTcVih06++4ZdqazrJRvwvC4bXedj9iEyQmDZW8w3+Wv8OWGGz9Jg1bG3RJWUQlZKQVN9txebLVwpO3BoeXum3+pcFonO CyCSu84V jUMfZH/v/xaJ5eIO3YAPTcxiPQVgZaLMUUGF2 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 Mon, Dec 19, 2022 at 09:08:31PM +0100, Borislav Petkov wrote: > On Mon, Dec 19, 2022 at 09:00:26AM -0600, Michael Roth wrote: > > We implemented this approach for v7, but it causes a fairly significant > > performance regression, particularly for the case for npages > 1 which > > this change was meant to optimize. > > > > I still need to dig in a big but I'm guessing it's related to flushing > > behavior. > > Well, AFAICT, change_page_attr_set_clr() flushes once at the end. > > Don't you need to flush when you modify the direct map? > > > It would however be nice to have a set_direct_map_default_noflush() > > variant that accepted a 'npages' argument, since it would be more > > performant here and also would potentially allow for restoring the 2M > > direct mapping in some cases. Will look into this more for v8. > > set_pages_direct_map_default_noflush() > > I guess. > > Although the name is a mouthful so I wouldn't mind having those > shortened. I had a patch that just adds numpages parameter: https://lore.kernel.org/lkml/20201123095432.5860-4-rppt@kernel.org/ The set_direct_map*() are not too widely used, so it's not a big deal to update all callers. > In any case, as long as that helper is properly defined and documented, > I don't mind. > > Thx. > > -- > Regards/Gruss, > Boris. > > https://people.kernel.org/tglx/notes-about-netiquette > -- Sincerely yours, Mike.