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charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260428-gmem-inplace-conversion-v5-13-d8608ccfca22@google.com> References: <20260428-gmem-inplace-conversion-v5-0-d8608ccfca22@google.com> In-Reply-To: <20260428-gmem-inplace-conversion-v5-0-d8608ccfca22@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, 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=1777418714; l=2437; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=2jwl4vZPlGQvOmnwH/oYNhanxNv5t/UdBGux+AjU5aQ=; b=1XrRoXlZ6YyE/8zRKL/CERwfqop5gZw5Z1bMhGmpG5iD5nCUiQ9BfUkM3SKtE7wFQPAeWBH9t qnBc56ZHLjWD+SmyF3p6GdHGVRlIhFa7pRDpwx9wFvKpRHafBXps6VW 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: k5eh184whaadz5aybwbmoc13hzjnqxdf X-Rspamd-Queue-Id: 7675340003 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1777418724-400687 X-HE-Meta: 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 /J2GIZSR NrwEtqEsXrq71H6EPQI0xnO9i6+PYQbUIIlEJX0QVcawQgRXtWvfuEf9+MJfb9tNl7Z2oJI2eMNW3KN490KXKVpZ4rA6ovAL+S2gd9gvL46OMcdO2cyIJWnlae9E1ut20w43OiCtJrTi69Q0Gx4/jLRL7UcmufErM8EB2SXrEdSeefVIjGMfmYDty/uFdn9lMj12oq02XXrcoXoAx/DstHmc8n2511xICHIaesQEp8Pp1nV6dl2+8p+k69RADhZlofBaNelocbgaDW6iTpNTrGlHDk9RFW0c+cuz4+82DKq2GESbj7B9vjtGi4+vdlR+1RcaA4yLjQZ5N9bVrjs57ZPc2tX+caE/YgSUhCC1E8DMLXdzej4cpYMc5tx5FMnpHfeurTwy9gdqL4KST5KxW2vLlOs8bYQNqSLTb2fjmNhLncEKBaUFq69KuJ2HInmIfP33NzQpbNmOy+kl8DvCiJ1CQvg== 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, 24 insertions(+), 9 deletions(-) diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index d563d80d4accb..d8bdb51c50cf0 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -92,6 +92,23 @@ 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) { @@ -667,6 +684,11 @@ static int __kvm_gmem_set_attributes(struct inode *inode, pgoff_t start, filemap_invalidate_lock(mapping); + if (kvm_gmem_range_has_attributes(mt, start, nr_pages, attrs)) { + r = 0; + goto out; + } + mas_init(&mas, mt, start); r = kvm_gmem_mas_preallocate(&mas, attrs, start, nr_pages); if (r) { @@ -1152,20 +1174,13 @@ 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, -- 2.54.0.545.g6539524ca2-goog