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charset="UTF-8" Introduce kvm_arch_supports_gmem() to explicitly indicate whether an architecture supports guest_memfd. Previously, kvm_arch_has_private_mem() was used to check for guest_memfd support. However, this conflated guest_memfd with "private" memory, implying that guest_memfd was exclusively for CoCo VMs or other private memory use cases. With the expansion of guest_memfd to support non-private memory, such as shared host mappings, it is necessary to decouple these concepts. The new kvm_arch_supports_gmem() function provides a clear way to check for guest_memfd support. Reviewed-by: Ira Weiny Reviewed-by: Gavin Shan Reviewed-by: Shivank Garg Reviewed-by: Vlastimil Babka Co-developed-by: David Hildenbrand Signed-off-by: David Hildenbrand Signed-off-by: Fuad Tabba --- arch/x86/include/asm/kvm_host.h | 4 +++- include/linux/kvm_host.h | 11 +++++++++++ virt/kvm/kvm_main.c | 4 ++-- 3 files changed, 16 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 66bdd0759d27..09f4f6240d9d 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -2271,8 +2271,10 @@ void kvm_configure_mmu(bool enable_tdp, int tdp_forced_root_level, #ifdef CONFIG_KVM_GMEM #define kvm_arch_has_private_mem(kvm) ((kvm)->arch.has_private_mem) +#define kvm_arch_supports_gmem(kvm) kvm_arch_has_private_mem(kvm) #else #define kvm_arch_has_private_mem(kvm) false +#define kvm_arch_supports_gmem(kvm) false #endif #define kvm_arch_has_readonly_mem(kvm) (!(kvm)->arch.has_protected_state) @@ -2325,7 +2327,7 @@ enum { #define HF_SMM_INSIDE_NMI_MASK (1 << 2) # define KVM_MAX_NR_ADDRESS_SPACES 2 -/* SMM is currently unsupported for guests with private memory. */ +/* SMM is currently unsupported for guests with guest_memfd private memory. */ # define kvm_arch_nr_memslot_as_ids(kvm) (kvm_arch_has_private_mem(kvm) ? 1 : 2) # define kvm_arch_vcpu_memslots_id(vcpu) ((vcpu)->arch.hflags & HF_SMM_MASK ? 1 : 0) # define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, (role).smm) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 359baaae5e9f..ab1bde048034 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -729,6 +729,17 @@ static inline bool kvm_arch_has_private_mem(struct kvm *kvm) } #endif +/* + * Arch code must define kvm_arch_supports_gmem if support for guest_memfd is + * enabled. + */ +#if !defined(kvm_arch_supports_gmem) && !IS_ENABLED(CONFIG_KVM_GMEM) +static inline bool kvm_arch_supports_gmem(struct kvm *kvm) +{ + return false; +} +#endif + #ifndef kvm_arch_has_readonly_mem static inline bool kvm_arch_has_readonly_mem(struct kvm *kvm) { diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 898c3d5a7ba8..afbc025ce4d3 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1588,7 +1588,7 @@ static int check_memory_region_flags(struct kvm *kvm, { u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES; - if (kvm_arch_has_private_mem(kvm)) + if (kvm_arch_supports_gmem(kvm)) valid_flags |= KVM_MEM_GUEST_MEMFD; /* Dirty logging private memory is not currently supported. */ @@ -4912,7 +4912,7 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) #endif #ifdef CONFIG_KVM_GMEM case KVM_CAP_GUEST_MEMFD: - return !kvm || kvm_arch_has_private_mem(kvm); + return !kvm || kvm_arch_supports_gmem(kvm); #endif default: break; -- 2.50.0.727.gbf7dc18ff4-goog