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charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260507-gmem-inplace-conversion-v6-13-91ab5a8b19a4@google.com> References: <20260507-gmem-inplace-conversion-v6-0-91ab5a8b19a4@google.com> In-Reply-To: <20260507-gmem-inplace-conversion-v6-0-91ab5a8b19a4@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, ira.weiny@intel.com, 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, tabba@google.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 , Baoquan He , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Youngjun Park , Qi Zheng , Shakeel Butt , Kiryl Shutsemau , Jason Gunthorpe , Vlastimil Babka 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 X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1778185365; l=2558; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=b2U3rQZtoe13iK85Md2FTyXx66OuI05q1gqdIbbHlSQ=; b=UN/8Y1orfcMwyEZH0S6RExPannjH51GfhVxr5vzN7x9jmFkjvni9/PmzSMTOUzMaLZLxQCqVH lSEBC+HA0RABt69qVqqsoI+XK5xrvF6Ruy0bRDp9YiSgwEBHz9IOKpv 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-Stat-Signature: 6f5yeheyos1q5nqb5j5gjj9bjqy8xaiy X-Rspam-User: X-Rspamd-Queue-Id: 509BD100003 X-Rspamd-Server: rspam07 X-HE-Tag: 1778185375-420304 X-HE-Meta: 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 aoALI2nR ApsYTLMZ0vtK+K+ylqaxKakROtOPg16jqpSsuZ03n/sT9EDG2GjQtaGE685XhJu+vpX3BOZkfQAcL8jiJh1K0vzfTgjKKCTcNkE9xWMRiE5mKVESfCieziJzr4BlSXgCXdPXAX9FN4LU8G2n6hxt0GjqTu3pasgHJ43qAQTGaJhTmU9RoEeGZOM7VGoHEQj+ASasg6ykHNBdj6raAwG1L4c0dXWXsSdO9Z4rbB2EgZFRE+AMD4FRssPn2Qr7KQ8wkU+IM6f0yq53PJ3BoaH1zsACluQyBGzeFNAdJuIFaf17rHSFxkg+ofHsMx0PPXux94KsJCgv8iFswCCts8uRMC2kKF3LnJzdZ2CPT6WjFJuW1W8YQdN8Y7TwB0vRJGuohU2TYAGIJrS+KOwowF9EAOGmYjhP8snB3tGGxC6vwav6boVJQ4TqMEH5j1HFAjo82/0F1nwb/dsnw0cXaA3DlnXPA2g== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Ackerley Tng Extract a helper out of kvm_gmem_range_is_private() that checks that a range has given attributes. Optimize setting memory attributes by returning early if all pages in the requested range already has the requested attributes. Signed-off-by: Ackerley Tng --- virt/kvm/guest_memfd.c | 33 +++++++++++++++++++++++---------- 1 file changed, 23 insertions(+), 10 deletions(-) diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index baf4b88dead1f..034b72b4947fb 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -86,6 +86,23 @@ 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 maple_tree *mt, + pgoff_t index, size_t nr_pages, + u64 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 (xa_to_value(entry) != attributes) + return false; + } + + return true; +} + static int __kvm_gmem_prepare_folio(struct kvm *kvm, struct kvm_memory_slot *slot, pgoff_t index, struct folio *folio) { @@ -649,12 +666,15 @@ 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(mt, start, nr_pages, attrs)) + goto out; + mas_init(&mas, mt, start); r = kvm_gmem_mas_preallocate(&mas, attrs, start, nr_pages); if (r) { @@ -1140,20 +1160,13 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_get_pfn); static bool kvm_gmem_range_is_private(struct gmem_inode *gi, pgoff_t index, size_t nr_pages, struct kvm *kvm, gfn_t gfn) { - pgoff_t end = index + nr_pages - 1; - void *entry; - if (vm_memory_attributes) return kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + nr_pages, KVM_MEMORY_ATTRIBUTE_PRIVATE, KVM_MEMORY_ATTRIBUTE_PRIVATE); - mt_for_each(&gi->attributes, entry, index, end) { - if (xa_to_value(entry) != KVM_MEMORY_ATTRIBUTE_PRIVATE) - return false; - } - - return true; + return kvm_gmem_range_has_attributes(&gi->attributes, index, nr_pages, + KVM_MEMORY_ATTRIBUTE_PRIVATE); } static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot, -- 2.54.0.563.g4f69b47b94-goog