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charset="UTF-8" X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: BB09720009 X-Stat-Signature: wyba47mju84kggxm8izg9yc45mmhjki5 X-Rspam-User: X-HE-Tag: 1749137904-28912 X-HE-Meta: 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 9Of6y0vP 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Ackerley Tng For memslots backed by guest_memfd with shared mem support, the KVM MMU must always fault in pages from guest_memfd, and not from the host userspace_addr. Update the fault handler to do so. This patch also refactors related function names for accuracy: kvm_mem_is_private() returns true only when the current private/shared state (in the CoCo sense) of the memory is private, and returns false if the current state is shared explicitly or impicitly, e.g., belongs to a non-CoCo VM. kvm_mmu_faultin_pfn_gmem() is updated to indicate that it can be used to fault in not just private memory, but more generally, from guest_memfd. Co-developed-by: David Hildenbrand Signed-off-by: David Hildenbrand Signed-off-by: Ackerley Tng Co-developed-by: Fuad Tabba Signed-off-by: Fuad Tabba --- arch/x86/kvm/mmu/mmu.c | 38 +++++++++++++++++++++++--------------- include/linux/kvm_host.h | 25 +++++++++++++++++++++++-- 2 files changed, 46 insertions(+), 17 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 2b6376986f96..5b7df2905aa9 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3289,6 +3289,11 @@ int kvm_mmu_max_mapping_level(struct kvm *kvm, return __kvm_mmu_max_mapping_level(kvm, slot, gfn, PG_LEVEL_NUM, is_private); } +static inline bool fault_from_gmem(struct kvm_page_fault *fault) +{ + return fault->is_private || kvm_gmem_memslot_supports_shared(fault->slot); +} + void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) { struct kvm_memory_slot *slot = fault->slot; @@ -4465,21 +4470,25 @@ 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, - u8 max_level, int gmem_order) +static u8 kvm_max_level_for_fault_and_order(struct kvm *kvm, + struct kvm_page_fault *fault, + int order) { - u8 req_max_level; + u8 max_level = fault->max_level; if (max_level == PG_LEVEL_4K) return PG_LEVEL_4K; - max_level = min(kvm_max_level_for_order(gmem_order), max_level); + max_level = min(kvm_max_level_for_order(order), max_level); if (max_level == PG_LEVEL_4K) return PG_LEVEL_4K; - req_max_level = kvm_x86_call(private_max_mapping_level)(kvm, pfn); - if (req_max_level) - max_level = min(max_level, req_max_level); + if (fault->is_private) { + u8 level = kvm_x86_call(private_max_mapping_level)(kvm, fault->pfn); + + if (level) + max_level = min(max_level, level); + } return max_level; } @@ -4491,10 +4500,10 @@ 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, - struct kvm_page_fault *fault) +static int kvm_mmu_faultin_pfn_gmem(struct kvm_vcpu *vcpu, + struct kvm_page_fault *fault) { - int max_order, r; + int gmem_order, r; if (!kvm_slot_has_gmem(fault->slot)) { kvm_mmu_prepare_memory_fault_exit(vcpu, fault); @@ -4502,15 +4511,14 @@ static int kvm_mmu_faultin_pfn_private(struct kvm_vcpu *vcpu, } r = kvm_gmem_get_pfn(vcpu->kvm, fault->slot, fault->gfn, &fault->pfn, - &fault->refcounted_page, &max_order); + &fault->refcounted_page, &gmem_order); if (r) { kvm_mmu_prepare_memory_fault_exit(vcpu, fault); return r; } 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_level_for_fault_and_order(vcpu->kvm, fault, gmem_order); return RET_PF_CONTINUE; } @@ -4520,8 +4528,8 @@ 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); + if (fault_from_gmem(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 6326d1ad8225..c1c76794b25a 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2524,10 +2524,31 @@ bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm, bool kvm_arch_post_set_memory_attributes(struct kvm *kvm, struct kvm_gfn_range *range); +/* + * Returns true if the given gfn's private/shared status (in the CoCo sense) is + * private. + * + * A return value of false indicates that the gfn is explicitly or implicitly + * shared (i.e., non-CoCo VMs). + */ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) { - return IS_ENABLED(CONFIG_KVM_GMEM) && - kvm_get_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE; + struct kvm_memory_slot *slot; + + if (!IS_ENABLED(CONFIG_KVM_GMEM)) + return false; + + slot = gfn_to_memslot(kvm, gfn); + if (kvm_slot_has_gmem(slot) && kvm_gmem_memslot_supports_shared(slot)) { + /* + * Without in-place conversion support, if a guest_memfd memslot + * supports shared memory, then all the slot's memory is + * considered not private, i.e., implicitly shared. + */ + return false; + } + + return kvm_get_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE; } #else static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) -- 2.49.0.1266.g31b7d2e469-goog