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[173.79.60.52]) by smtp.gmail.com with ESMTPSA id af79cd13be357-939e190f8c3sm78468885a.17.2026.09.10.06.40.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Sep 2026 06:40:30 -0700 (PDT) Date: Thu, 10 Sep 2026 09:40:28 -0400 From: Gregory Price To: "David Hildenbrand (Arm)" Cc: linux-mm@kvack.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, pbonzini@redhat.com, seanjc@google.com, akpm@linux-foundation.org, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, ying.huang@linux.alibaba.com, apopple@nvidia.com, shuah@kernel.org Subject: Re: [PATCH 0/5] KVM: guest_memfd: bind backing memory to a NUMA node Message-ID: References: <20260902194657.79075-1-gourry@gourry.net> <9b67424d-70e5-442b-9ec7-22b1d3db12f4@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9b67424d-70e5-442b-9ec7-22b1d3db12f4@kernel.org> X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 8312840009 X-Stat-Signature: cy4hex56tghqyzqtckjb1fjyn9mqxbit X-HE-Tag: 1789047631-235577 X-HE-Meta: U2FsdGVkX19IZPeJeBrD8+Ufi9jbhqATK6XcE3D791t68Ws3SFdqQUip/f2TZqcVuh2nS8+FuBjKzA0bd+7WSTnYiiRvrzZO1GElVJJEaU5oqrOKblBC1CnHzWrBpZJnDWxhHsb5ZVyMPghIU1tv7vV7TJOf6/+02AVBoPuT8WcScJBqQuZsNRmX+xmYGzLrVRvQyOlJEo27DJFhkdDk+h1mdLM6V2QE0muuyu/AoaWgW0qMhb1mWwUnoR3ku+IY0Jj/BatL0bxF+0f6uueIBLTlmMUjRg930gvyMbN2msqWJfr/vxX1y+3UhALNrwBNcI+473zHGnun+2Mwk1VQ0fdc+Vdq+KHb2UPs5aqPngANcADN6b1cjzTdDq5sh5sc4hArsyzvAh07Y9LIJoQFxfNh2AsLBdGF55j1ObsuDDJDnFTqyZR1jTuunWJeXP8YCglsNoCPfy+zL02z3BAyjC7CPY+h+GLExbl/o92VfGqctQbR+iOfsK5l20CN7rVG61NQYr9Whxyyjbkt9RjwOtuTwxffAu0ZSmV5jTFawUz+VVoKpiVC9wJs444PkFuP/FEXjnnBBZbf0XdUjq2Cvp5TSkPIeT1i5IffX/MC6PdS7JnqsBJORIugNxccvxIXCsAnSoHjFff3mzyUmG8ugdXusf9pBiIOj5UwTAqkdzAbn5l+EMBwSRTVWv32SKbgFAiWF2t/OX5GTBZrB5Us7JLTJlo280B7ESqK7pOnonwPLkXFcRcW/8zY6RDAXyaAT1EbGjtCqEOXXy1iyMG/KO3yp9DMfAckmGucX3RZQnEjtufkHXMY/XdNSGlK9Y+6r1Y9jwLuyzW0q3jBjkZrG9iitseM/dZS9xVu/LUlTeLxIC0eZbTdjX8ThPfGc2xX8ahO83rYTbn33tH+rC+nJQOxoVIuEE01V0pEz+vIsgMAUzdXqp491oczSV3wKU+pkpA/3viewrJpNLp8H0U v3CZPTDe DVa51yaMOvcp8wPaujYsBf3vBZSYTiwbfAB6sl6jyaRVjd7vYiu8vbkccFICf9Ti/vtE1AANRUcnLD7pLqBIiQ+5dXq3nJLNuOqLTeIvIwmZGMUsQK6Qh1Jfpkc0l3eRop2htw3gV4Rwp1Wa6bgGPorhzNXsKXscLDG3jQTWUjMQSBCQoq5PpIXekGAbsibLBQdOSM8Bxs0U3BtkGcPVkieBWuUa0j/LdG6jIblGFAFuen5D0E2FMGcqn92SOvVqloL0TTwjjuMbd1m9tBATXGJ5gELCojNZu90NAAi4GeLmRr1B34MJldLEns4uHucmLVME7JkWx+M6/pOJM2Ej9O3wrNmg+M69OYNDL4yCMKZoTYzATfuHoLiZFjQz9G2tH+djsAAf8aVSauDFUjLyc4bx5e10feY6b6VuDIi4WkkTTTFt9YjA+UVlZMQrIQtHzME3nIN7PIHX/ghY= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Sep 10, 2026 at 01:30:04PM +0200, David Hildenbrand (Arm) wrote: > On 9/2/26 21:46, Gregory Price wrote: > > guest_memfd allocates its folios through a per-inode shared mempolicy. > > > > Today that policy can only be set after the fact, with mbind() on a host > > mmap of the fd. That requires the fd to be mappable, and it cannot reach > > folios that are only ever guest-faulted. Neither holds for a > > non-mappable (confidential) guest_memfd. > > That looks like an investment into a mechanism we will soon consider legacy, so > I am not convinced this is the right approach? > Hm, I think i've missed recent work in this space / this context. Any suggested reading here? Don't want to eat too much of your time. ~Gregory