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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=1789084533; l=2021; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=aWC7q7TfOQBRXxfaI/bprLobieqMQa31lPnqLIZNQQg=; b=IvM3zmLIvg3kdTU+xjwTpru5AZjxzSMMBzH6CkhOdmQqNSixiQVfVxaHsotMs8RT9igbUQ1Y6 YahMx5Iaz/2Dg1du2b9n8m84m0G29Yr2OT1rQuH/JBCvLFK9otOyy2P 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 X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: D4B61100003 X-Stat-Signature: miry8hr3acnz7bj656b4ptq1xyfgz447 X-HE-Tag: 1789084544-720333 X-HE-Meta: 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 1KhVB9Cu hEx5zHR5xhhDs02SSEHgVc5YjRjt/8is5PJfLNvWn/h+6MphF9Dug88xUYO5rs1rLA9PIlUG9ag0uHZrNt/FSzQ/gbkHOQ7lHdMeyifwxmJQvgXjkXdL2zuxwkJIJtSViTsc91YX20EyoYSc6w1g3wyLjdbbQgYEGpYuD1ullfu0yYengdYXKzDWlZnCaG2g7fQlhFEJGG3CVqpOp0lh1rapsbpY0kiNGT+6j4I2npipadbF0yHCl9GnlT6xobbWJf9s1GqECMWOBzLO2i5+H8SIhKsP3MXIh1uZ6LW9io4SthJZVoORTqnWSQLhl3C1/TI2PK95fc2yQGfrQPMOPqIna5Mikgh1c2fuWJ7G2t3RCkxxSMUugjFrKKZ2e9flkpJOvOD64CzRo/ZjQU9QsDXtcJWu+7Urvyw1QINIfYTM7dojNDXwpLFQvenez+d0EMQDEBuoAhhZJVGd+rIwGqyijnaurBKZYKiKaqdPYAL6TE9RP5eSW4XgApXdTCRUwxytMpHSy4OH+Gi545W4g3mPJ82jfCSmsfkaf Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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. Signed-off-by: Ackerley Tng Tested-by: Shivank Garg Reviewed-by: Fuad Tabba Reviewed-by: Binbin Wu Reviewed-by: Xiaoyao Li Reviewed-by: David Hildenbrand (Arm) --- 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 85446fe720603..f1c36e99cd3ce 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -99,6 +99,24 @@ 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. @@ -636,12 +654,15 @@ 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) { -- 2.55.0.1007.g17ff1f9808-goog