From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 793E130F533; Mon, 31 Aug 2026 00:25:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788135921; cv=none; b=VjEpQ/H528Rl87F7LNmie9RquYSOvykdwB5RJ7u513ywkcpqmJDRPj9SKnJKZRapJ+p7+aYj7fQr7A+/hUSN34Uscyth05HIAzFawiB7GenSZr1NQUXp8cda7EDVD02jD0CiTLbuyDJEL3XsAbbHvSXULQiINOXu4B8Ovhxv8u4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788135921; c=relaxed/simple; bh=0u7TejSHMad9bYL2p6sJmzMrRCXcgVnE5lch746jIL0=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=KV7vkG7xM8t7r2kWsQZCUUz2agw5MTSRGN/QFv1vBUwfSOU7dPfQTteiGrA3cNgcLsRFbVUpa/8djCJohLvTt6Jt8C7ElGZ7aRfUuchkwx3FO2/sXBKJm/PlAKQPD+l4RJdCKPex0oEAr550Pqiq/H0mX+oDWz/FZyBxPfiPdEA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Q4XDKKI9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Q4XDKKI9" Received: by smtp.kernel.org (Postfix) with ESMTPS id 5A0A7C2BD01; Mon, 31 Aug 2026 00:25:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1788135921; bh=0u7TejSHMad9bYL2p6sJmzMrRCXcgVnE5lch746jIL0=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=Q4XDKKI970cDwrlLeOUyPXzL41fHU8ixKdjKvqGjaArmtm3P47QWIbAtRhaNOzqyb +1i/fJnnXYIf3u/mZ8lMtWzBTvlYBxs9+ErohCEzzYLLMjA/3yE66N1ASko4Gq81dG pndUl+FiJaAZRQTFsTP7SBd7DYFlV48y28KYOklloq6f51TTC+9J2A3EmaY6+s4AWv 60p1/q0rVQTJQn8RTpTCqKxMrJZc/MCnwzHODOapdLD+Fg3Vrg5zvFwPxLP7NMKIeN h1TH9DbipEWqk0soO5LzCrkaHmA6OmlViW/Ze8+jBEntG4wkOCmDMddn5bnkIfTXFY MXvuZUpRMzEQw== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38934C61DE4; Mon, 31 Aug 2026 00:25:21 +0000 (UTC) From: Ackerley Tng via B4 Relay Date: Sun, 30 Aug 2026 17:25:18 -0700 Subject: [PATCH v12 17/45] KVM: guest_memfd: Return early if range already has requested attributes Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260830-gmem-inplace-conversion-v12-17-85e5fd25252a@google.com> References: <20260830-gmem-inplace-conversion-v12-0-85e5fd25252a@google.com> In-Reply-To: <20260830-gmem-inplace-conversion-v12-0-85e5fd25252a@google.com> To: aik@amd.com, andrew.jones@linux.dev, binbin.wu@linux.intel.com, brauner@kernel.org, chao.p.peng@linux.intel.com, david@kernel.org, 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, 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 , Sean Christopherson , 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 , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Youngjun Park , Qi Zheng , Shakeel Butt , Kiryl Shutsemau , Baoquan He , Jason Gunthorpe , John Hubbard , Peter Xu , tarunsahu@google.com, Randy Dunlap , Lorenzo Stoakes , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jason Gunthorpe , Fuad Tabba , Vlastimil Babka , Baoquan He Cc: 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, Ackerley Tng , Xiaoyao Li X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1788135915; l=1963; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=9VNi9pEuvRkZvdOHV26sDWiemmZK8/yVnQLh7gIYUDA=; b=CFxkPT3CEVpS6OYk5q/nJQbCjkiuG38jxjI0AEn8ybxQssVnDPdSR4CXvx5zB8nUH7yz3IHXZ FIdLJl85tJiBVhY6bcB+H02CGuqGFpIwiDvHRM0IWlde4lr2+MEuRAp X-Developer-Key: i=ackerleytng@google.com; a=ed25519; pk=sAZDYXdm6Iz8FHitpHeFlCMXwabodTm7p8/3/8xUxuU= X-Endpoint-Received: by B4 Relay for ackerleytng@google.com/20260225 with auth_id=649 X-Original-From: Ackerley Tng Reply-To: ackerleytng@google.com From: Ackerley Tng Provide a function to check that a range has given attributes. Optimize setting memory attributes by returning early if all pages in the requested range already have the requested attributes. Reviewed-by: Fuad Tabba Tested-by: Shivank Garg Reviewed-by: Binbin Wu Reviewed-by: Xiaoyao Li Signed-off-by: Ackerley Tng --- virt/kvm/guest_memfd.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index d14a7024bdc7b..ac8e0c6d6e942 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -98,6 +98,24 @@ static bool kvm_gmem_is_shared_mem(struct inode *inode, pgoff_t index) return !kvm_gmem_is_private_mem(inode, index); } +static bool kvm_gmem_range_has_attributes(struct inode *inode, + pgoff_t index, size_t nr_pages, + u64 attributes) +{ + struct maple_tree *mt = &GMEM_I(inode)->attributes; + pgoff_t end = index + nr_pages - 1; + void *entry; + + lockdep_assert(mt_lock_is_held(mt)); + + mt_for_each(mt, entry, index, end) { + if (kvm_gmem_get_attributes(inode, entry) != attributes) + return false; + } + + return true; +} + /* * Returns a locked folio on success. The caller is responsible for * setting the up-to-date flag before the memory is mapped into the guest. @@ -623,12 +641,15 @@ static int __kvm_gmem_set_attributes(struct inode *inode, pgoff_t start, pgoff_t end = start + nr_pages; struct maple_tree *mt; struct ma_state mas; - int r; + int r = 0; mt = &gi->attributes; filemap_invalidate_lock(mapping); + if (kvm_gmem_range_has_attributes(inode, start, nr_pages, attrs)) + goto out; + mas_init(&mas, mt, start); r = kvm_gmem_mas_preallocate(&mas, attrs, start, nr_pages); if (r) { -- 2.55.0.897.gb25b4bd76c-goog