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AJvYcCVY4a1Nxq3mrnPiBdsKZmhdj/JoeqboOFiQ6tuwST9EseJjNjvJXwsMNE+qz+heXXFgqaDHjzEozBHBXmfY@vger.kernel.org X-Gm-Message-State: AOJu0YzdMy7gBx3Uvw4AjDS+sKalPi8r5b8cm0ZTQzWbwY6YigsYXAp1 vsmFT4eeNWgMDAmC1KM0bmVfSm/6Wju02cqeUTEI7ZWgIbaPMcsDmaQehFuJj4M3kM8BlbOcdw= = X-Google-Smtp-Source: AGHT+IETFauGFsHYOJjw4CSDyJ0tdvCZM93gDYVKoGoQHbFjxmQvhxMExSQAfHqlOSGTi6uXKyM5+m3cQQ== X-Received: from wmbjx12.prod.google.com ([2002:a05:600c:578c:b0:440:595d:fba9]) (user=tabba job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:4e09:b0:43d:5ec:b2f4 with SMTP id 5b1f17b1804b1-441b1f35490mr48191655e9.10.1746032229343; Wed, 30 Apr 2025 09:57:09 -0700 (PDT) Date: Wed, 30 Apr 2025 17:56:48 +0100 In-Reply-To: <20250430165655.605595-1-tabba@google.com> Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250430165655.605595-1-tabba@google.com> X-Mailer: git-send-email 2.49.0.967.g6a0df3ecc3-goog Message-ID: <20250430165655.605595-7-tabba@google.com> Subject: [PATCH v8 06/13] KVM: x86: Generalize private fault lookups to guest_memfd fault lookups From: Fuad Tabba To: kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mm@kvack.org Cc: pbonzini@redhat.com, chenhuacai@kernel.org, mpe@ellerman.id.au, anup@brainfault.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, seanjc@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, akpm@linux-foundation.org, xiaoyao.li@intel.com, yilun.xu@intel.com, chao.p.peng@linux.intel.com, jarkko@kernel.org, amoorthy@google.com, dmatlack@google.com, isaku.yamahata@intel.com, mic@digikod.net, vbabka@suse.cz, vannapurve@google.com, ackerleytng@google.com, mail@maciej.szmigiero.name, david@redhat.com, michael.roth@amd.com, wei.w.wang@intel.com, liam.merwick@oracle.com, isaku.yamahata@gmail.com, kirill.shutemov@linux.intel.com, suzuki.poulose@arm.com, steven.price@arm.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_tsoni@quicinc.com, quic_svaddagi@quicinc.com, quic_cvanscha@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, catalin.marinas@arm.com, james.morse@arm.com, yuzenghui@huawei.com, oliver.upton@linux.dev, maz@kernel.org, will@kernel.org, qperret@google.com, keirf@google.com, roypat@amazon.co.uk, shuah@kernel.org, hch@infradead.org, jgg@nvidia.com, rientjes@google.com, jhubbard@nvidia.com, fvdl@google.com, hughd@google.com, jthoughton@google.com, peterx@redhat.com, pankaj.gupta@amd.com, tabba@google.com Until now, faults to private memory backed by guest_memfd are always consumed from guest_memfd whereas faults to shared memory are consumed from anonymous memory. Subsequent patches will allow sharing guest_memfd backed memory in-place, and mapping it by the host. Faults to in-place shared memory should be consumed from guest_memfd as well. In order to facilitate that, generalize the fault lookups. Currently, only private memory is consumed from guest_memfd and therefore as it stands, this patch does not change the behavior. Co-developed-by: David Hildenbrand Signed-off-by: David Hildenbrand Signed-off-by: Fuad Tabba --- arch/x86/kvm/mmu/mmu.c | 19 +++++++++---------- include/linux/kvm_host.h | 6 ++++++ 2 files changed, 15 insertions(+), 10 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 6d5dd869c890..08eebd24a0e1 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3258,7 +3258,7 @@ static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn, static int __kvm_mmu_max_mapping_level(struct kvm *kvm, const struct kvm_memory_slot *slot, - gfn_t gfn, int max_level, bool is_private) + gfn_t gfn, int max_level, bool is_gmem) { struct kvm_lpage_info *linfo; int host_level; @@ -3270,7 +3270,7 @@ static int __kvm_mmu_max_mapping_level(struct kvm *kvm, break; } - if (is_private) + if (is_gmem) return max_level; if (max_level == PG_LEVEL_4K) @@ -3283,10 +3283,9 @@ static int __kvm_mmu_max_mapping_level(struct kvm *kvm, int kvm_mmu_max_mapping_level(struct kvm *kvm, const struct kvm_memory_slot *slot, gfn_t gfn) { - bool is_private = kvm_slot_has_gmem(slot) && - kvm_mem_is_private(kvm, gfn); + bool is_gmem = kvm_slot_has_gmem(slot) && kvm_mem_from_gmem(kvm, gfn); - return __kvm_mmu_max_mapping_level(kvm, slot, gfn, PG_LEVEL_NUM, is_private); + return __kvm_mmu_max_mapping_level(kvm, slot, gfn, PG_LEVEL_NUM, is_gmem); } void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) @@ -4465,7 +4464,7 @@ static inline u8 kvm_max_level_for_order(int order) return PG_LEVEL_4K; } -static u8 kvm_max_private_mapping_level(struct kvm *kvm, kvm_pfn_t pfn, +static u8 kvm_max_gmem_mapping_level(struct kvm *kvm, kvm_pfn_t pfn, u8 max_level, int gmem_order) { u8 req_max_level; @@ -4491,7 +4490,7 @@ static void kvm_mmu_finish_page_fault(struct kvm_vcpu *vcpu, r == RET_PF_RETRY, fault->map_writable); } -static int kvm_mmu_faultin_pfn_private(struct kvm_vcpu *vcpu, +static int kvm_mmu_faultin_pfn_gmem(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) { int max_order, r; @@ -4509,8 +4508,8 @@ static int kvm_mmu_faultin_pfn_private(struct kvm_vcpu *vcpu, } fault->map_writable = !(fault->slot->flags & KVM_MEM_READONLY); - fault->max_level = kvm_max_private_mapping_level(vcpu->kvm, fault->pfn, - fault->max_level, max_order); + fault->max_level = kvm_max_gmem_mapping_level(vcpu->kvm, fault->pfn, + fault->max_level, max_order); return RET_PF_CONTINUE; } @@ -4521,7 +4520,7 @@ static int __kvm_mmu_faultin_pfn(struct kvm_vcpu *vcpu, unsigned int foll = fault->write ? FOLL_WRITE : 0; if (fault->is_private) - return kvm_mmu_faultin_pfn_private(vcpu, fault); + return kvm_mmu_faultin_pfn_gmem(vcpu, fault); foll |= FOLL_NOWAIT; fault->pfn = __kvm_faultin_pfn(fault->slot, fault->gfn, foll, diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index d9616ee6acc7..cdcd7ac091b5 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2514,6 +2514,12 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) } #endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */ +static inline bool kvm_mem_from_gmem(struct kvm *kvm, gfn_t gfn) +{ + /* For now, only private memory gets consumed from guest_memfd. */ + return kvm_mem_is_private(kvm, gfn); +} + #ifdef CONFIG_KVM_GMEM int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn, kvm_pfn_t *pfn, struct page **page,