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Peter Anvin" , Paolo Bonzini , Wanpeng Li , Vitaly Kuznetsov , Andy Lutomirski , Frederic Weisbecker , "Paul E. McKenney" , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Andrew Morton , Uladzislau Rezki , Christoph Hellwig , Lorenzo Stoakes , Josh Poimboeuf , Jason Baron , Kees Cook , Sami Tolvanen , Ard Biesheuvel , Nicholas Piggin , Juerg Haefliger , Nicolas Saenz Julienne , "Kirill A. Shutemov" , Nadav Amit , Dan Carpenter , Chuang Wang , Yang Jihong , Petr Mladek , "Jason A. Donenfeld" , Song Liu , Julian Pidancet , Tom Lendacky , Dionna Glaze , Thomas =?iso-8859-1?Q?Wei=DFschuh?= , Juri Lelli , Marcelo Tosatti , Yair Podemsky , Daniel Wagner , Petr Tesarik Subject: Re: [RFC PATCH v3 13/15] context_tracking,x86: Add infrastructure to defer kernel TLBI Message-ID: <20241121153016.GL39245@noisy.programming.kicks-ass.net> References: <20241119153502.41361-1-vschneid@redhat.com> <20241119153502.41361-14-vschneid@redhat.com> <20241120152216.GM19989@noisy.programming.kicks-ass.net> <20241120153221.GM38972@noisy.programming.kicks-ass.net> <20241121111221.GE24774@noisy.programming.kicks-ass.net> <4b562cd0-7500-4b3a-8f5c-e6acfea2896e@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4b562cd0-7500-4b3a-8f5c-e6acfea2896e@intel.com> X-Rspamd-Server: rspam10 X-Stat-Signature: 7taemccxu911dfrnp8mc8d5m6g8kes8y X-Rspamd-Queue-Id: 42B9C120027 X-Rspam-User: X-HE-Tag: 1732202970-844638 X-HE-Meta: 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 jF1fBLVp PPJux5REeoda2vYDqN1cJ6PlwUK5Dy3xkHCvPTERLEBXaj1gXTyByZfizyuue5AUOBm9ir9njf+WEu8DRRKSfO1+7J10wufS5/OjmLglnRtxp8e6BJROE7uqWaEqfgnzLXnVdXMY7p2UfUaN3RuLqrZZUQrleJA69oWXc2pHrF6daT8Pb4uL2dwihe2gbcHN05G+iR5nS5FEy3dNMEUehtdgT0bPGPgl6BPlBp46433sd1HjBdwCKtfI9JxC200VrdFiSVFAdAWvR4S7fuKcAP0JaXElkdU+Lm9uxhJsujbpje3Ts8P8l0xUKPQ== 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: List-Subscribe: List-Unsubscribe: On Thu, Nov 21, 2024 at 07:07:44AM -0800, Dave Hansen wrote: > On 11/21/24 03:12, Peter Zijlstra wrote: > >> I see e.g. ds_clear_cea() clears PTEs that can have the _PAGE_GLOBAL flag, > >> and it correctly uses the non-deferrable flush_tlb_kernel_range(). > > > > I always forget what we use global pages for, dhansen might know, but > > let me try and have a look. > > > > I *think* we only have GLOBAL on kernel text, and that only sometimes. > > I think you're remembering how _PAGE_GLOBAL gets used when KPTI is in play. Yah, I suppose I am. That was the last time I had a good look at this stuff :-) > Ignoring KPTI for a sec... We use _PAGE_GLOBAL for all kernel mappings. > Before PCIDs, global mappings let the kernel TLB entries live across CR3 > writes. When PCIDs are in play, global mappings let two different ASIDs > share TLB entries. Hurmph.. bah. That means we do need that horrible CR4 dance :/