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AJvYcCUno0vRQ4QE6RhNxQzgNsfwqZYZfNXRF8Z2Rpj3qRuUutKks1lACOhzN8s4NM9ANg3V1WJurJRm/TymBz4=@vger.kernel.org X-Gm-Message-State: AOJu0YyWo0ojrXc3yyMamW7/840bcfFS87/FSer6l51mJAJTWDOnyOP8 9a2GIPwkUCsOvhM1QxxlPcKZw15HtCcFWBjJN4kV9RlVUK2b2vCbyqDKPCNF+lWZ8urzVOe5v0X g3yB+T/09N9AswuleNkWPL28ETA== X-Google-Smtp-Source: AGHT+IGjtEU34dqqnybB19rBgoWD/tF1TyeATlVnN+HcnvWeM3cm6kpWoOjHHimLdS4u0Zp3tLd6gH6GokckyTqWLA== X-Received: from pjbbk24.prod.google.com ([2002:a17:90b:818:b0:33b:a0ae:940]) (user=ackerleytng job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:cecb:b0:290:c94b:8381 with SMTP id d9443c01a7336-290c9c89dbbmr63619355ad.7.1760731958742; Fri, 17 Oct 2025 13:12:38 -0700 (PDT) Date: Fri, 17 Oct 2025 13:11:47 -0700 In-Reply-To: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.51.0.858.gf9c4a03a3a-goog Message-ID: Subject: [RFC PATCH v1 06/37] KVM: guest_memfd: Update kvm_gmem_populate() to use gmem attributes From: Ackerley Tng To: cgroups@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, x86@kernel.org Cc: ackerleytng@google.com, akpm@linux-foundation.org, binbin.wu@linux.intel.com, bp@alien8.de, brauner@kernel.org, chao.p.peng@intel.com, chenhuacai@kernel.org, corbet@lwn.net, dave.hansen@intel.com, dave.hansen@linux.intel.com, david@redhat.com, dmatlack@google.com, erdemaktas@google.com, fan.du@intel.com, fvdl@google.com, haibo1.xu@intel.com, hannes@cmpxchg.org, hch@infradead.org, hpa@zytor.com, hughd@google.com, ira.weiny@intel.com, isaku.yamahata@intel.com, jack@suse.cz, james.morse@arm.com, jarkko@kernel.org, jgg@ziepe.ca, jgowans@amazon.com, jhubbard@nvidia.com, jroedel@suse.de, jthoughton@google.com, jun.miao@intel.com, kai.huang@intel.com, keirf@google.com, kent.overstreet@linux.dev, liam.merwick@oracle.com, maciej.wieczor-retman@intel.com, mail@maciej.szmigiero.name, maobibo@loongson.cn, mathieu.desnoyers@efficios.com, maz@kernel.org, mhiramat@kernel.org, mhocko@kernel.org, mic@digikod.net, michael.roth@amd.com, mingo@redhat.com, mlevitsk@redhat.com, mpe@ellerman.id.au, muchun.song@linux.dev, nikunj@amd.com, nsaenz@amazon.es, oliver.upton@linux.dev, palmer@dabbelt.com, pankaj.gupta@amd.com, paul.walmsley@sifive.com, pbonzini@redhat.com, peterx@redhat.com, pgonda@google.com, prsampat@amd.com, pvorel@suse.cz, qperret@google.com, richard.weiyang@gmail.com, rick.p.edgecombe@intel.com, rientjes@google.com, rostedt@goodmis.org, roypat@amazon.co.uk, rppt@kernel.org, seanjc@google.com, shakeel.butt@linux.dev, shuah@kernel.org, steven.price@arm.com, steven.sistare@oracle.com, suzuki.poulose@arm.com, tabba@google.com, tglx@linutronix.de, thomas.lendacky@amd.com, vannapurve@google.com, vbabka@suse.cz, viro@zeniv.linux.org.uk, vkuznets@redhat.com, wei.w.wang@intel.com, will@kernel.org, willy@infradead.org, wyihan@google.com, xiaoyao.li@intel.com, yan.y.zhao@intel.com, yilun.xu@intel.com, yuzenghui@huawei.com, zhiquan1.li@intel.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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. Signed-off-by: Ackerley Tng Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu/mmu.c | 2 +- include/linux/kvm_host.h | 5 ++++- virt/kvm/guest_memfd.c | 26 +++++++++++++++++++++++--- virt/kvm/kvm_main.c | 8 +++----- 4 files changed, 31 insertions(+), 10 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index e4542b37b0db6..52189853cf4ab 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -7897,7 +7897,7 @@ static bool hugepage_has_attrs(struct kvm *kvm, struc= t kvm_memory_slot *slot, const unsigned long end =3D start + KVM_PAGES_PER_HPAGE(level); =20 if (level =3D=3D 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); =20 for (gfn =3D start; gfn < end; gfn +=3D 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 b8418cc5851f1..b48632ee242b3 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2535,12 +2535,15 @@ static inline bool kvm_mem_is_private(struct kvm *k= vm, gfn_t gfn) #endif =20 #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES -bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t e= nd, +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 #endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */ =20 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 f62facc3ab776..855e682041311 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -907,10 +907,30 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memo= ry_slot *slot, EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_get_pfn); =20 #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 =3D 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) !=3D attributes) + return false; + } + + return true; +} + long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src,= long npages, kvm_gmem_populate_cb post_populate, void *opaque) { struct kvm_memory_slot *slot; + struct gmem_inode *gi; void __user *p; =20 int ret =3D 0, max_order; @@ -929,6 +949,8 @@ long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn= , void __user *src, long if (!file) return -EFAULT; =20 + gi =3D GMEM_I(file_inode(file)); + filemap_invalidate_lock(file->f_mapping); =20 npages =3D min_t(ulong, slot->npages - (start_gfn - slot->base_gfn), npag= es); @@ -962,9 +984,7 @@ long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn= , void __user *src, long (npages - i) < (1 << max_order)); =20 ret =3D -EINVAL; - while (!kvm_range_has_memory_attributes(kvm, gfn, gfn + (1 << max_order), - KVM_MEMORY_ATTRIBUTE_PRIVATE, - KVM_MEMORY_ATTRIBUTE_PRIVATE)) { + while (!kvm_gmem_range_is_private(gi, index, 1 << max_order, kvm, gfn)) { if (!max_order) goto put_folio_and_exit; max_order--; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index c73ebdb73070e..35166754a22b4 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -103,9 +103,7 @@ module_param(allow_unsafe_mappings, bool, 0444); =20 #ifdef CONFIG_KVM_MEMORY_ATTRIBUTES #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES -static bool vm_memory_attributes =3D true; -#else -#define vm_memory_attributes false +bool vm_memory_attributes =3D true; #endif DEFINE_STATIC_CALL_RET0(__kvm_get_memory_attributes, kvm_get_memory_attrib= utes_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(str= uct 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 e= nd, +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); =20 /* 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; =20 /* --=20 2.51.0.858.gf9c4a03a3a-goog