From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793800972; b=roHg6M4MQSA2N/H5bK5oulfxRc8nGrfjhjPKXBUsLMo5EinjaIJQwTR8L5s5ROZuRUhD oaYCAdpkB/1ow4KJsFhVI6/IraVY5Xzch7Gh4eOdU2TzBvefn8SmA3cuf+9F232As/6qL lIhsGL2ETvR6/7TkB4m1B654LWg25IqSqs4VFgLz34KTVDRzpqeOr9Ps2czYVyuQ2xgLE Kj1MzrOms/fW4jn2oRzoT0Q0a5msgaJqjNyyXgF0hQqZBRF8W+Y+WO0wBAU3BFrvFFSm9 tbn4PLDo3YfkrvJ4WqAkjvmUXoYA5uNPbzdvOnNfzYGGiIhQVk7N6nSxYHdum/AvLjg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793800972; h=Received:DKIM-Signature:X-Mailer:From:To:Cc:Subject:In-Reply-To: References:Date:Message-ID:MIME-Version:Content-Type; bh=p1t0XcRRp1uMVDh1EBUHkAU5r0BAD30gdP7oa2ssEps=; b=DTUCOI90OFsd10YKXETbEZRIibzSoREVkuwq+OTvgX1EMKrAtDZdUWxj6LuIRFEUt1U5 FAzudFIDVopfLeR+VOEcP8uI22QnjxELtsucGxTHOAXuNN0ML2+aWtGscZgyI1z6QTwSr hU67r9vj9tlRM8iaGycNTUsJRsIQ8H1Hm/iS+QsqZLSDVFG00yLKuVjLxT5UtsuEoW6aV 3UOVZxHbpcmwJe40AP+8dHP+uHmluEGxf6ag6zyoGkveZ/SBToPId06FA2/YAFj9KG9cK Xodm/ntaSiUVCeoWbcx5ntwHo8xP1jqvCTq5Z+5tuOcbCO6xskyk08csNzWjmjYNR2A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="C5HXHYT/"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1E374606A326; Wed, 4 Nov 2026 14:02:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=C5HXHYT/ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C2AB1F00A02; Wed, 4 Nov 2026 14:02:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793800971; bh=p1t0XcRRp1uMVDh1EBUHkAU5r0BAD30gdP7oa2ssEps=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=C5HXHYT/oKFLRoX6O0NeJ3VHnhU6UIcl5iX0mNecPKLfoDtWRDh88e3yxAHD4YpVg sIIZ13Mkev8qZk12GaC6xsWb4OGKFaQ4KIHqvyRgi/hDR9I4HJue8L0XKprGAd//35 XxhVpW8a6t1Y6XqHKqqfG00NK0hzfX8x8dn9fYxjO0Nrew3DZ8ObEoz4BOGJ9HDHXg 3/3OnFCi3LwWbpw0Ob++1VqYZE/ZlbAMbaEf3cFEqQ4mNHTAhlKAjWnSsdcrlv0twy Dr80Gh7r7qYsPtTUJy04MMXp5Xaa8CvGFxFsVEEgowhEKGMe136+lpI8efO1YBpQCK Ge1JTw4xfCP4Q== X-Mailer: emacs 31.1 (via feedmail 11-beta-1 I) From: Aneesh Kumar K.V To: Ackerley Tng , linux-coco@lists.linux.dev Cc: Alex Williamson , David Woodhouse , David Hildenbrand , Jason Gunthorpe , "Joerg Roedel (AMD)" , Kevin Tian , Paolo Bonzini , Robin Murphy , Sean Christopherson , Will Deacon , Alexey Kardashevskiy , Xu Yilun , Catalin Marinas , Suzuki K Poulose , Steven Price , Fred Griffoul , iommu@lists.linux.dev, kvm@vger.kernel.org, patches@lists.linux.dev Subject: Re: [RFC PATCH v3 06/13] KVM: guest_memfd: Support device-backed PFN providers In-Reply-To: References: <20261101071928.2462549-1-aneesh.kumar@kernel.org> <20261101071928.2462549-7-aneesh.kumar@kernel.org> Date: Wed, 04 Nov 2026 19:32:42 +0530 Message-ID: X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain Ackerley Tng writes: > "Aneesh Kumar K.V (Arm)" writes: > >> Device resources such as PCI BARs supply PFNs directly and cannot use >> the folio allocation path. Store the mapping owner and device ID in the >> core context during attach(), and use them when preparing device >> memslots. Keep device memory separate from ordinary PFN-backed RAM. >> > > I'm really hoping that device providers are just another kind of PFN > providers and not special in some way. > > Please give me some time to prototype so I can see what can't be > achieved. > Please take a look at the cca/topics/cca-da-gmem-backend-v4 branch in: https://git.gitlab.arm.com/linux-arm/linux-cca.git It documents the differences in detail. -aneesh