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AFNElJ9ADo9Ksix/s3SsILpLG6B5TZP2WteQ22qulY5FXf2KoqubHEOY7bPwHjFVER0xl0el9XmRGIAvQA==@kvack.org X-Gm-Message-State: AOJu0YxcKOJBmzMtlH23Qtkx6UOshIkjTBuIPbVD8XS3zqF1hVHp9W15 Pz93ro0mCuIgKSpqsGU/1yaX4p0s9X8STi1wGVmjDqrSlMRf2Wkyb53Qw55TQJ//JaExMbEXt0Q nQNGaEA== X-Received: from pfwp41.prod.google.com ([2002:a05:6a00:26e9:b0:842:5fa6:3103]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:5210:b0:36a:1ed8:6fe6 with SMTP id 98e67ed59e1d1-370f0b58cefmr4684526a91.24.1780684078907; Fri, 05 Jun 2026 11:27:58 -0700 (PDT) Date: Fri, 5 Jun 2026 11:27:58 -0700 In-Reply-To: Mime-Version: 1.0 References: <20260522-gmem-inplace-conversion-v7-0-2f0fae496530@google.com> Message-ID: Subject: Re: [PATCH v7 00/42] guest_memfd: In-place conversion support From: Sean Christopherson To: Ackerley Tng Cc: Ackerley Tng via B4 Relay , aik@amd.com, andrew.jones@linux.dev, binbin.wu@linux.intel.com, brauner@kernel.org, chao.p.peng@linux.intel.com, david@kernel.org, ira.weiny@intel.com, jmattson@google.com, jthoughton@google.com, michael.roth@amd.com, oupton@kernel.org, pankaj.gupta@amd.com, qperret@google.com, rick.p.edgecombe@intel.com, rientjes@google.com, shivankg@amd.com, steven.price@arm.com, tabba@google.com, willy@infradead.org, wyihan@google.com, yan.y.zhao@intel.com, forkloop@google.com, pratyush@kernel.org, suzuki.poulose@arm.com, aneesh.kumar@kernel.org, liam@infradead.org, Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Shuah Khan , Shuah Khan , Vishal Annapurve , Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Youngjun Park , Qi Zheng , Shakeel Butt , Kiryl Shutsemau , Jason Gunthorpe , Vlastimil Babka , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev Content-Type: text/plain; charset="us-ascii" X-Rspamd-Queue-Id: 760D980006 X-Stat-Signature: u9jii9h44i5juobgs5ccutryhwe6ww4y X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1780684080-496445 X-HE-Meta: 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 N/j7qHYD 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Jun 04, 2026, Ackerley Tng wrote: > Sean Christopherson writes: > >> + KVM: selftests: Test conversion with elevated page refcount > >> + Askar pointed out that soon vmsplice may not pin pages. Should I > >> pin pages through CONFIG_GUP_TEST like in [2]? I prefer not to > >> take a dependency on CONFIG_GUP_TEST. > > > > I'm not exactly excited about taking a dependency on CONFIG_GUP_TEST either, but > > it probably is the least awful choice. E.g. KVM also pins pages is certain flows, > > but we're _also_ actively working to remove the need to pin. > > > > Hmm, maybe IORING_REGISTER_PBUF_RING? AFAICT, it's almost literally a "pin user > > memory" syscall. > > > > Hmm that takes a dependency on io_uring, which isn't always compiled > in. Between CONFIG_IO_URING and CONFIG_GUP_TEST, I'd rather > CONFIG_GUP_TEST. Or try both? If it's not a ridiculous amount of work.