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 9B2AE26ED40; Wed, 29 Jul 2026 00:35:08 +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=1785285308; cv=none; b=V/RNtFV1MSPHBFYNj99Ue/2s/o2RSo2p+vBf9YYVIPCuxtCWjwO0KejZ7HzsrP571vdA/easMXa2btEStGvhgkV70Bjwmplbxstoi84sgjalDsV5dVR3xxXMhqXDdbidjR4L1JdfREvCZXnUpd/5Ns5E4aX87tW/LXwRg0MvgWg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785285308; c=relaxed/simple; bh=YU2W/e9zoY8XRLjAHDI08WdN2EsH395vdkPJNoccJg4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=H9SP5vFw43xKuv7gMiViVgXiMXxY/LICKREY9UDwcVaS0NEW/0zPLh4Zk4O5X7oo+DDZBlvKgMOHgN87QoYsS3ZDcOc1cXRv77gIwXf/95gXNnmY4itplc0m4W5KNvvHHUnjCmZKL4u4QQPBhn/HonxsfkSUnZqt4wkPlP6nRUQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iLuQJT2g; 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="iLuQJT2g" Received: by smtp.kernel.org (Postfix) with ESMTPS id 43CC3C2BD04; Wed, 29 Jul 2026 00:35:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1785285308; bh=YU2W/e9zoY8XRLjAHDI08WdN2EsH395vdkPJNoccJg4=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=iLuQJT2gnRe5Ejz0zTxyOY8hkf6rWZP3jfLjbT2JJE8oC5zGXURlkYCpvK0acmuwA P3hW+880DCyGvFu2zF15nSwyFD4Cd0pdTTEGKQPLDgt2f+874hHzH/nrSLmtIjZPC9 oSJUHwXdDdk2+7Y3jXMqhk9rhq0vEkBRHfXWt914CUFAMuqOBrFwli8NK6Ewd3y0/V Chi5469qE9MIqphx72dk72P60pVUqNvqLmardP8ZbLX8DCU8/kIO9+uTc4gzE9cvAF z1ffULI/mLHfHjUv0GaisLvoeq5zpJtiWmFBTN5V6Fgne92fwYRnzVQrIDZhwBejIV a5ViQd+Y97GGQ== 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 2BB63C54F4D; Wed, 29 Jul 2026 00:35:08 +0000 (UTC) From: Ackerley Tng via B4 Relay Date: Tue, 28 Jul 2026 17:35:06 -0700 Subject: [PATCH v9 07/41] KVM: guest_memfd: Wire up core private/shared attribute interfaces Precedence: bulk X-Mailing-List: linux-trace-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: <20260728-gmem-inplace-conversion-v9-7-35f9aec2aed2@google.com> References: <20260728-gmem-inplace-conversion-v9-0-35f9aec2aed2@google.com> In-Reply-To: <20260728-gmem-inplace-conversion-v9-0-35f9aec2aed2@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 , 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 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