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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 , Jason Gunthorpe , 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 X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1785285305; l=4904; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=Khc6sycubGrfoJCb/kBxgxJ7UDuxLVJB5MenqDESOq8=; b=c/JKNYH+h7dgoAGoTZo/8qTYbeNkf3QS755Gf97nN6FnguidBdhiMdZ4OfzZK7DSDrl3bLd4l tjElD8FU2xUBYgOf4Tg9CW7t1Se5AjSPj25c1x5+i3J/ohAwM5mSBBL 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: 3035BA0012 X-Stat-Signature: a433971rusoihjz59ptduzpr5je4jomp X-HE-Tag: 1785285310-539977 X-HE-Meta: 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 sXQCsU8D 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Sean Christopherson With in-place conversion, guest_memfd is able to track the private/shared status of memory. Use a global flag to toggle between tracking private/shared status per-vm or within guest_memfd. When queried for supported vm memory attributes, return 0 if attributes are tracked in guest_memfd. When querying for memory attributes over a range, look up memory attributes based on the flag's state at query time. For per-GFN memory attribute queries, choose an implementation (VM or guest_memfd lookup) at KVM load time. The flag is always false for now and will be made toggle-able after all in-place conversion features are added in subsequent patches. If/since the flag is false, if CONFIG_KVM_VM_MEMORY_ATTRIBUTES is also not selected, the per-GFN memory attribute query defaults to returning 0 (false/not private). Signed-off-by: Sean Christopherson Reviewed-by: Fuad Tabba Tested-by: Shivank Garg Co-developed-by: Ackerley Tng Signed-off-by: Ackerley Tng --- include/linux/kvm_host.h | 4 ++++ virt/kvm/guest_memfd.c | 25 ++++++++++++++++++++++--- virt/kvm/kvm_main.c | 12 +++++++++++- 3 files changed, 37 insertions(+), 4 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 73f564b87a324..a913dd57ae622 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2579,6 +2579,8 @@ static inline bool kvm_vm_mem_is_private(struct kvm *kvm, gfn_t gfn) #endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */ #ifdef kvm_arch_has_private_mem +extern bool gmem_in_place_conversion; + typedef bool (kvm_mem_is_private_t)(struct kvm *kvm, gfn_t gfn); DECLARE_STATIC_CALL(__kvm_mem_is_private, kvm_mem_is_private_t); @@ -2587,6 +2589,8 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) return static_call(__kvm_mem_is_private)(kvm, gfn); } #else +#define gmem_in_place_conversion false + static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) { return false; diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 33c9830190e2e..89cf922232920 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -893,6 +893,27 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_get_pfn); #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE +static bool kvm_range_is_private(struct file *file, pgoff_t index, + size_t nr_pages, struct kvm *kvm, gfn_t gfn) +{ + struct inode *inode = file_inode(file); + pgoff_t last = index + nr_pages - 1; + struct maple_tree *mt; + void *entry; + + if (!gmem_in_place_conversion) + return kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + nr_pages, + KVM_MEMORY_ATTRIBUTE_PRIVATE, + KVM_MEMORY_ATTRIBUTE_PRIVATE); + + mt = &GMEM_I(inode)->attributes; + mt_for_each(mt, entry, index, last) { + if (kvm_gmem_interpret_entry(inode, entry) != + KVM_MEMORY_ATTRIBUTE_PRIVATE) + return false; + } + return true; +} static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot, struct file *file, gfn_t gfn, struct page *src_page, @@ -913,9 +934,7 @@ static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot, folio_unlock(folio); - if (!kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + 1, - KVM_MEMORY_ATTRIBUTE_PRIVATE, - KVM_MEMORY_ATTRIBUTE_PRIVATE)) { + if (!kvm_range_is_private(file, index, 1, kvm, gfn)) { ret = -EINVAL; goto out_put_folio; } diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 80317d2c15d07..0dfc91b9478ce 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -101,6 +101,10 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(halt_poll_ns_shrink); static bool __ro_after_init allow_unsafe_mappings; module_param(allow_unsafe_mappings, bool, 0444); +#ifdef kvm_arch_has_private_mem +bool __ro_after_init gmem_in_place_conversion = false; +#endif + /* * Ordering of locks: * @@ -2422,6 +2426,9 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm, static u64 kvm_supported_vm_mem_attributes(struct kvm *kvm) { #ifdef kvm_arch_has_private_mem + if (gmem_in_place_conversion) + return 0; + if (!kvm || kvm_arch_has_private_mem(kvm)) return KVM_MEMORY_ATTRIBUTE_PRIVATE; #endif @@ -2633,8 +2640,11 @@ EXPORT_STATIC_CALL_GPL(__kvm_mem_is_private); static void kvm_init_memory_attributes(void) { + if (gmem_in_place_conversion) + static_call_update(__kvm_mem_is_private, kvm_gmem_is_private); #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES - static_call_update(__kvm_mem_is_private, kvm_vm_mem_is_private); + else + static_call_update(__kvm_mem_is_private, kvm_vm_mem_is_private); #endif } #else -- 2.55.0.508.g3f0d502094-goog