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Thu, 13 Nov 2025 13:25:54 -0800 (PST) X-Google-Smtp-Source: AGHT+IFG7adQ+To1sVTkWH9kHmWTxIW7v+qGjRIswi48je30/xk/DlGdUNhUX3w4qos3uFEoeFPyIQ== X-Received: by 2002:ac8:5888:0:b0:4ed:bbca:fdec with SMTP id d75a77b69052e-4edf2048486mr20165981cf.16.1763069153946; Thu, 13 Nov 2025 13:25:53 -0800 (PST) Received: from x1.local ([142.188.210.50]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8b2aef2fa3bsm204086285a.36.2025.11.13.13.25.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 13 Nov 2025 13:25:53 -0800 (PST) Date: Thu, 13 Nov 2025 16:25:49 -0500 From: Peter Xu To: Xiaoyao Li Cc: qemu-devel@nongnu.org, Paolo Bonzini , Fabiano Rosas , Chenyi Qiang , David Hildenbrand , Alexey Kardashevskiy , Juraj Marcin Subject: Re: [PATCH 4/8] memory: Rename RAM_GUEST_MEMFD to RAM_GUEST_MEMFD_PRIVATE Message-ID: References: <20251023185913.2923322-1-peterx@redhat.com> <20251023185913.2923322-5-peterx@redhat.com> <872f9349-7d3d-4b7b-9ba9-bcbc44c9afe5@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <872f9349-7d3d-4b7b-9ba9-bcbc44c9afe5@intel.com> Received-SPF: pass client-ip=170.10.129.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, Oct 24, 2025 at 05:17:20PM +0800, Xiaoyao Li wrote: > On 10/24/2025 2:59 AM, Peter Xu wrote: > > This name is too generic, and can conflict with in-place guest-memfd > > support. Add a _PRIVATE suffix to show what it really means: it is always > > silently using an internal guest-memfd to back a shared host backend, > > rather than used in-place. > > > > This paves way for in-place guest-memfd, which means we can have a ramblock > > that allocates pages completely from guest-memfd (private or shared). > > It's for patch 4-7. Regarding the rename. How about: > > - RAM_GUEST_MEMFD => RAM_PRIVATE_MEMORY > - backend->guest_memfd => backend->private_memory > - machine_require_guest_memfd() => machine_require_private_memory() > - cgs->require_guest_memfd => cgs->require_private_memory > > For CoCo VMs, what they require is the support of private memory, while the > guest_memfd is how linux provides private memory support. But with mmap > support added to guest memfd, it can serve as shared/non-private memory as > well. Futher, in the future when in-place conversion support is implemented, > a single guest memfd can serve as both shared and private in different > parts. So guest_memfd_private will be confusing at that time. That's more or less a valid point. Said so, I think PRIVATE_MEMORY is confusing too v.s. RAM_PRIVATE. See: commit 6169f1193657d0ba630a2ce33cef639ae918bce4 Author: Steve Sistare Date: Wed Jan 15 11:00:31 2025 -0800 memory: add RAM_PRIVATE Not to mention its possible confusion against mmap(MAP_PRIVATE) which is even more well known (where here RAM_PRIVATE is exactly about it). It'll not be a concern until private gmemfd will start to back shared memories, even if it happens (I believe it will, a matter of time..) IMHO it's still fine to use guest_memfd_private, because here private describes that the fd is a private FD (not the memory is private). It's private because it's hidden inside each ramblock that matters. Then a fd that is private can still back shared memories. Would you mind I keep everything as-is for now? Thanks, -- Peter Xu