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AJvYcCWIQeHL82aXa2e0mQ5VFj7hJIqRXtM5o//7Rqn/3rrwk1fbsLjTgpO1FUlQnoYwp33QJsKhgP2LYg==@kvack.org X-Gm-Message-State: AOJu0YzMchEp1/vXi9QqTK6vA824HO2j5WV6Ttd4HzH2fSw5Zk8a1Ngc jTBYvztNHdIR3bBH0LTb2uK7zbnd0Ea9OyHHOpwqz0RAdgB2w2ToeiTXmNoYCuKd5dbDZ78iLMa RxYwNkh9kKJ9fl9M28cdYCv+g2w== X-Received: from pgbcr6.prod.google.com ([2002:a05:6a02:4106:b0:c73:c1e2:84e7]) (user=ackerleytng job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:431d:b0:38d:ee4a:e82f with SMTP id adf61e73a8af0-39c87c4aed6mr312128637.63.1774563876758; Thu, 26 Mar 2026 15:24:36 -0700 (PDT) Date: Thu, 26 Mar 2026 15:24:15 -0700 In-Reply-To: <20260326-gmem-inplace-conversion-v4-0-e202fe950ffd@google.com> Mime-Version: 1.0 References: <20260326-gmem-inplace-conversion-v4-0-e202fe950ffd@google.com> X-Developer-Key: i=ackerleytng@google.com; a=ed25519; pk=sAZDYXdm6Iz8FHitpHeFlCMXwabodTm7p8/3/8xUxuU= X-Developer-Signature: v=1; a=ed25519-sha256; t=1774563861; l=5802; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=vymNc3F4VBBGneenNd8IucPbAr1SdMuDYSLrejXwwUQ=; b=1LWUYI7gs645uKY5pvp+JN0SJPLpfIcJb5vTHCCN4uONoDtA/ZkQwB57ZGcilNgQcL6dc3IRn laHi/lbCytrCWoczD6QHAkpcw7DrsnR7zLOahw4n2P3/9JSmm1eBIJs X-Mailer: b4 0.14.3 Message-ID: <20260326-gmem-inplace-conversion-v4-6-e202fe950ffd@google.com> Subject: [PATCH RFC v4 06/44] KVM: guest_memfd: Update kvm_gmem_populate() to use gmem attributes From: Ackerley Tng 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, jroedel@suse.de, 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 , 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, Ackerley Tng Content-Type: text/plain; charset="utf-8" X-Rspamd-Server: rspam12 X-Stat-Signature: raa1pjfysy7grqgsd7wjw5hgzehymqkq X-Rspamd-Queue-Id: 7777B40008 X-Rspam-User: X-HE-Tag: 1774563878-829848 X-HE-Meta: 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 zjc0TLXX 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Update the guest_memfd populate() flow to pull memory attributes from the gmem instance instead of the VM when KVM is not configured to track shared/private status in the VM. Rename the per-VM API to make it clear that it retrieves per-VM attributes, i.e. is not suitable for use outside of flows that are specific to generic per-VM attributes. Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson Signed-off-by: Ackerley Tng --- arch/x86/kvm/mmu/mmu.c | 2 +- include/linux/kvm_host.h | 14 +++++++++++++- virt/kvm/guest_memfd.c | 24 +++++++++++++++++++++--- virt/kvm/kvm_main.c | 8 +++----- 4 files changed, 38 insertions(+), 10 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 792701b093234..f21e16f22dd7b 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -7978,7 +7978,7 @@ static bool hugepage_has_attrs(struct kvm *kvm, struct kvm_memory_slot *slot, const unsigned long end = start + KVM_PAGES_PER_HPAGE(level); if (level == PG_LEVEL_2M) - return kvm_range_has_memory_attributes(kvm, start, end, ~0, attrs); + return kvm_range_has_vm_memory_attributes(kvm, start, end, ~0, attrs); for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) { if (hugepage_test_mixed(slot, gfn, level - 1) || diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 0f84421b3f49e..19f026f8de390 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2534,12 +2534,24 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) #endif #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES -bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end, +extern bool vm_memory_attributes; +bool kvm_range_has_vm_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end, unsigned long mask, unsigned long attrs); bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm, struct kvm_gfn_range *range); bool kvm_arch_post_set_memory_attributes(struct kvm *kvm, struct kvm_gfn_range *range); +#else +#define vm_memory_attributes false +static inline bool kvm_range_has_vm_memory_attributes(struct kvm *kvm, + gfn_t start, gfn_t end, + unsigned long mask, + unsigned long attrs) +{ + WARN_ONCE(1, "Unexpected call to kvm_range_has_vm_memory_attributes()"); + + return false; +} #endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */ unsigned long kvm_gmem_get_memory_attributes(struct kvm *kvm, gfn_t gfn); diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 6f4252c8b3f59..b6ffa8734175d 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -936,12 +936,31 @@ 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 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; +} static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot, struct file *file, gfn_t gfn, struct page *src_page, kvm_gmem_populate_cb post_populate, void *opaque) { pgoff_t index = kvm_gmem_get_index(slot, gfn); + struct gmem_inode *gi; struct folio *folio; kvm_pfn_t pfn; int ret; @@ -956,9 +975,8 @@ static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot, folio_unlock(folio); - if (!kvm_range_has_memory_attributes(kvm, gfn, gfn + 1, - KVM_MEMORY_ATTRIBUTE_PRIVATE, - KVM_MEMORY_ATTRIBUTE_PRIVATE)) { + gi = GMEM_I(file_inode(file)); + if (!kvm_gmem_range_is_private(gi, 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 7bb59679c9316..70b594dafc5cc 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -104,9 +104,7 @@ module_param(allow_unsafe_mappings, bool, 0444); #ifdef CONFIG_KVM_MEMORY_ATTRIBUTES #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES -static bool vm_memory_attributes = true; -#else -#define vm_memory_attributes false +bool vm_memory_attributes = true; #endif DEFINE_STATIC_CALL_RET0(__kvm_get_memory_attributes, kvm_get_memory_attributes_t); EXPORT_SYMBOL_FOR_KVM_INTERNAL(STATIC_CALL_KEY(__kvm_get_memory_attributes)); @@ -2457,7 +2455,7 @@ static unsigned long kvm_get_vm_memory_attributes(struct kvm *kvm, gfn_t gfn) * Returns true if _all_ gfns in the range [@start, @end) have attributes * such that the bits in @mask match @attrs. */ -bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end, +bool kvm_range_has_vm_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end, unsigned long mask, unsigned long attrs) { XA_STATE(xas, &kvm->mem_attr_array, start); @@ -2591,7 +2589,7 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end, mutex_lock(&kvm->slots_lock); /* Nothing to do if the entire range has the desired attributes. */ - if (kvm_range_has_memory_attributes(kvm, start, end, ~0, attributes)) + if (kvm_range_has_vm_memory_attributes(kvm, start, end, ~0, attributes)) goto out_unlock; /* -- 2.53.0.1018.g2bb0e51243-goog