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=1793804688; b=oNFGtAqg/52YwugogggWhdlbEDKZ7v5O3Oq5yQaHIBZPPbP5QArkw5aXpsFVlahNR4nu nnaDPD0EX2/nn3//tU5GAEhck144/fPAAstGTnYlRefnaYUB3g0EqWE51OqOyYRSE/6b9 j6q8pE435oMg1wItrKLunKzdwE+qQFz+zC8alHYdHLCqgZS3JhF7P8kqZvac5Cla7UYxT 9jhme0DaufoenWk4PzmsIQThaOK0GDFjOnGIeIZUtNIBCxbqaxcF2cfeenrqC4e7Gu8BH 7BFbzQQ34/ix2HILFkvyPC4Vte9F/Z1E6ASjlblYIJLcqjFjtqMyOOsetGavekKUONg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793804688; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=rS40NRoMRb1Axjjj6DLrLlKdWsMdXuRqZ21vY/yTWC4=; b=CZhR48wDA43P/0qfAVjGw3jkHsin6rsw7UlUhFAPa5SFjsCp2q/3gB2vl9xNP2WgilJq HBsviBnpvf2mG7RCUspaNYUYYixzgrWi8OEFlVq6sV6GR1d8dOrjSgBJIMkzvzkloAZvr zMXPplqSzDhliaGc4TEeXIYRMYVm8lzahH9UXWeRUV2o0rr4WnAxwQ8pCBG+T9ves4hmV EUkgPxhBdqQqfkH+GoHMncbpAPpvEh3tKgqpvbqpjTXjQ156iUJeMvIE42479L7CW18+u nx+BbZy/LTt5zqQp2cGrG8uVr2rmfuhvP/eOCUFPZ8+wMrRdrnSFKEsX2TUq4rfRQXQ== 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=krUATiSa; 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 86482606A33E; Wed, 4 Nov 2026 15:04:48 +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=krUATiSa Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8D86B1F000C1; Wed, 4 Nov 2026 15:04:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793804688; bh=rS40NRoMRb1Axjjj6DLrLlKdWsMdXuRqZ21vY/yTWC4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=krUATiSaTdc5CcZdzxygeRGDWGOF+1KIfBcpsteqisvuJzbk/ZRcl8A5IMmjEfKbD DqBpYtxQNQktX1ttfPg1DcfUGCCpZ3Z8m9XIBmN70PKQ60pI2ZjrKwkvZoru7OfuHF 1qI4JMj07swSks4IW4xh025Xa6upRn4/ht+zwOcGRkU5qlf7k/N2POfepYAE37Z6Bi pVecfsaLIB/HhJCPlu5ZsPp3sym/iHk5ekIcosNYx1EmSbsUo/9uS5OhQkrPdj/a7S HQDOiORokzmOAtD2m9H72Ou3aK+mXkCs6uYolzoq0f+9J6bI/uXskIvaWjhXVIP1bh utXPeW4f8x9jQ== From: "Aneesh Kumar K.V (Arm)" To: linux-coco@lists.linux.dev Cc: "Aneesh Kumar K.V (Arm)" , Ackerley Tng , Alex Williamson , David Woodhouse , David Hildenbrand , Jason Gunthorpe , "Joerg Roedel (AMD)" , Kevin Tian , Paolo Bonzini , Robin Murphy , Sean Christopherson , 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: [RFC PATCH v4 12/25] KVM: guest_memfd: Invalidate mappings before memslot unbind Date: Wed, 4 Nov 2026 20:33:09 +0530 Message-ID: <20261104150322.3516320-13-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20261104150322.3516320-1-aneesh.kumar@kernel.org> References: <20261104150322.3516320-1-aneesh.kumar@kernel.org> 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-Transfer-Encoding: 8bit Use the generic invalidate_start/end helpers to remove shared and private device mappings before removing the memslot's guest_memfd binding. Hold gmem_provider_lock() across invalidation and binding removal to prevent device unlock from racing with teardown. Keep the file attributes and has_private_ranges unchanged. Deleting a memslot removes mappings but does not share the backing range. Device unlock remains blocked until userspace shares the private ranges or closes the last guest_memfd reference. Cc: Paolo Bonzini Cc: Sean Christopherson Cc: David Hildenbrand Cc: kvm@vger.kernel.org Cc: patches@lists.linux.dev Signed-off-by: Aneesh Kumar K.V (Arm) --- virt/kvm/guest_memfd.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index d3de2e7bb9f5..870fe11c1c5c 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -1873,6 +1873,8 @@ void kvm_gmem_unbind(struct kvm_memory_slot *slot) unsigned long start = slot->gmem.pgoff; unsigned long end = start + slot->npages; struct gmem_file *f; + struct gmem_inode *gi; + enum kvm_gfn_range_filter filter; /* * Nothing to do if the underlying file was _already_ closed, as @@ -1892,8 +1894,13 @@ void kvm_gmem_unbind(struct kvm_memory_slot *slot) * drops slots_lock, so there's no need to verify the file is live. */ f = file->private_data; + gi = GMEM_I(file_inode(file)); + filter = kvm_gmem_get_all_gfns_filter(file_inode(file)); filemap_invalidate_lock(file->f_mapping); + gmem_provider_lock(gi); + __kvm_gmem_invalidate_start(f, start, end, filter); + __kvm_gmem_invalidate_end(f, start, end); xa_store_range(&f->bindings, start, end - 1, NULL, GFP_KERNEL); /* @@ -1902,6 +1909,7 @@ void kvm_gmem_unbind(struct kvm_memory_slot *slot) * to guarantee kvm_gmem_get_pfn() can't see the slot+file. */ WRITE_ONCE(slot->gmem.file, NULL); + gmem_provider_unlock(gi); filemap_invalidate_unlock(file->f_mapping); } -- 2.43.0