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 371AE22D781; Fri, 19 Jun 2026 00:31:48 +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=1781829108; cv=none; b=dEG19v5Lsw4EBNHMv0UpuAeQ1fE2eBdxyjcCVlv22TFE2nxWDzNUj2AVZFQl2ODsKoubOoQZbvdzBB6nin+jZWanNgJaiW7u053oLP5kLjkkrbVAgwtbklWASNx3FnHye0Hj3i+QtQTsEvcjnwFTUEoCrE1NT5uBGsDNi1GHie0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781829108; c=relaxed/simple; bh=05np0kXD+1HBAH7Gncn5wqrhYUmgbGkv7Y+NsUcBfHQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=tHdLxvWdrFsR+oWse/1CCU9xTNwbXjjIew1Oik7oY2RcwdNsJfIx1h2q3uerp2BJfhamWCrfob44qFidGCJSeFA/zrFzWlQLr1+DHKqNnfGD8JwY/6DMKh4CZIlEMmVSHh/sUZFuKmKD9dfO/6S8rbv46Pk1l+m8m2Nj5wErKqY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=X7AupsXW; 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="X7AupsXW" Received: by smtp.kernel.org (Postfix) with ESMTPS id AF6B2C4AF0C; Fri, 19 Jun 2026 00:31:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1781829107; bh=05np0kXD+1HBAH7Gncn5wqrhYUmgbGkv7Y+NsUcBfHQ=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=X7AupsXW60gtNP2MQTOW4/73lQ1R/RPs6lrpd/fY0ph7LpBxzJSmYHJxGVicT0Rio v678ZF47iEIKkj9gwsncmfUqBjccrqjwJIsvxrjyMmItve3uIox/1ZjWVIyckOL4wh 3q+5d6zpHuBuahIj2ViK/tO/vwWvhA0r2gmkfYrQudCABulqX2V12mhSDiNSNGZHxg GyrFtiwRPf83bwN7OfOq58w3z0dCVKExnwFpf2fnvf03gZ+hs7rSNsyQGCnb+RtbPX xwb5lf1yb/J4r7PN6ej+U0rpwL4c6sxfFA+rSSxdGNpjdmIu4Ify7kHIYvEsgPgfZ2 j29b7rCTcc2+Q== 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 A2ACFCD98FE; Fri, 19 Jun 2026 00:31:47 +0000 (UTC) From: Ackerley Tng via B4 Relay Date: Thu, 18 Jun 2026 17:31:47 -0700 Subject: [PATCH v8 10/46] KVM: guest_memfd: Wire up core private/shared attribute interfaces Precedence: bulk X-Mailing-List: linux-kernel@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: <20260618-gmem-inplace-conversion-v8-10-9d2959357853@google.com> References: <20260618-gmem-inplace-conversion-v8-0-9d2959357853@google.com> In-Reply-To: <20260618-gmem-inplace-conversion-v8-0-9d2959357853@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, 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 , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Youngjun Park , Qi Zheng , Shakeel Butt , Kiryl Shutsemau , Baoquan He , 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=1781829104; l=4770; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=fOfywxdTO/Whh+2RzVAHLLfy1oRrTLQnZ+x+DH1XTyQ=; b=aaYGk9KsmcaKJOqUgBq9hpVZyNGJXy22b6TtABP59Y1iKXqmq3CHRYIz1a8ITgKIMdzMR+tZ6 4SbI1OwN+YYCBGfJ6ejj9djCaIeXmuq2/AJHq3RfZgvSqrBwIfRZqXd 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: 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, choosing 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). Co-developed-by: Ackerley Tng Signed-off-by: Ackerley Tng Signed-off-by: Sean Christopherson --- include/linux/kvm_host.h | 4 ++++ virt/kvm/guest_memfd.c | 22 +++++++++++++++++++--- virt/kvm/kvm_main.c | 12 +++++++++++- 3 files changed, 34 insertions(+), 4 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 27687fb9d5201..acb552745b428 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2560,6 +2560,8 @@ static inline bool kvm_mem_range_is_private(struct kvm *kvm, gfn_t start, #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); @@ -2568,6 +2570,8 @@ 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 bca912db5be6e..e0e544ef47d69 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -926,6 +926,24 @@ 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_gmem_range_is_private(struct file *file, pgoff_t index, + size_t nr_pages, struct kvm *kvm, gfn_t gfn) +{ + struct maple_tree *mt = &GMEM_I(file_inode(file))->attributes; + pgoff_t end = index + nr_pages - 1; + 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_for_each(mt, entry, index, end) { + if (xa_to_value(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, @@ -946,9 +964,7 @@ 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_gmem_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 8b238e461b854..01761f6e25d25 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.rc0.738.g0c8ab3ebcc-goog