diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 2e481864ec19..7d0761cb46b3 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -472,8 +472,12 @@ struct kvm_vcpu_arch { /* vcpu power state */ struct kvm_mp_state mp_state; - /* Cache some mmu pages needed inside spinlock regions */ - struct kvm_mmu_memory_cache mmu_page_cache; + union { + /* Cache some mmu pages needed inside spinlock regions */ + struct kvm_mmu_memory_cache mmu_page_cache; + /* Pages to be donated to pkvm/EL2 if it runs out */ + struct kvm_hyp_memcache pkvm_memcache; + }; /* Target CPU and feature flags */ int target; diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h index cc7aa2c1bba0..a91c3ad6db0b 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h @@ -57,6 +57,7 @@ extern struct host_mmu host_mmu; enum pkvm_component_id { PKVM_ID_HOST, PKVM_ID_HYP, + PKVM_ID_GUEST, }; extern unsigned long hyp_nr_cpus; @@ -67,6 +68,7 @@ int __pkvm_host_unshare_hyp(u64 pfn); int __pkvm_host_reclaim_page(u64 pfn); int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages); int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages); +int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu); bool addr_is_memory(phys_addr_t phys); int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot); diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 9afc3164c153..60f90af7dafc 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -578,11 +578,21 @@ struct pkvm_mem_transition { struct { u64 completer_addr; } hyp; + struct { + struct pkvm_hyp_vcpu *hyp_vcpu; + } guest; }; } initiator; struct { enum pkvm_component_id id; + + union { + struct { + struct pkvm_hyp_vcpu *hyp_vcpu; + phys_addr_t phys; + } guest; + }; } completer; }; @@ -846,6 +856,52 @@ static int hyp_complete_donation(u64 addr, return pkvm_create_mappings_locked(start, end, prot); } +static enum pkvm_page_state guest_get_page_state(kvm_pte_t pte) +{ + if (!kvm_pte_valid(pte)) + return PKVM_NOPAGE; + + return pkvm_getstate(kvm_pgtable_stage2_pte_prot(pte)); +} + +static int __guest_check_page_state_range(struct pkvm_hyp_vcpu *vcpu, u64 addr, + u64 size, enum pkvm_page_state state) +{ + struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu); + struct check_walk_data d = { + .desired = state, + .get_page_state = guest_get_page_state, + }; + + hyp_assert_lock_held(&vm->lock); + return check_page_state_range(&vm->pgt, addr, size, &d); +} + +static int guest_ack_share(u64 addr, const struct pkvm_mem_transition *tx, + enum kvm_pgtable_prot perms) +{ + u64 size = tx->nr_pages * PAGE_SIZE; + + if (perms != KVM_PGTABLE_PROT_RWX) + return -EPERM; + + return __guest_check_page_state_range(tx->completer.guest.hyp_vcpu, + addr, size, PKVM_NOPAGE); +} + +static int guest_complete_share(u64 addr, const struct pkvm_mem_transition *tx, + enum kvm_pgtable_prot perms) +{ + struct pkvm_hyp_vcpu *vcpu = tx->completer.guest.hyp_vcpu; + struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu); + u64 size = tx->nr_pages * PAGE_SIZE; + enum kvm_pgtable_prot prot; + + prot = pkvm_mkstate(perms, PKVM_PAGE_SHARED_BORROWED); + return kvm_pgtable_stage2_map(&vm->pgt, addr, size, tx->completer.guest.phys, + prot, &vcpu->vcpu.arch.pkvm_memcache); +} + static int check_share(struct pkvm_mem_share *share) { const struct pkvm_mem_transition *tx = &share->tx; @@ -867,6 +923,9 @@ static int check_share(struct pkvm_mem_share *share) case PKVM_ID_HYP: ret = hyp_ack_share(completer_addr, tx, share->completer_prot); break; + case PKVM_ID_GUEST: + ret = guest_ack_share(completer_addr, tx, share->completer_prot); + break; default: ret = -EINVAL; } @@ -895,6 +954,9 @@ static int __do_share(struct pkvm_mem_share *share) case PKVM_ID_HYP: ret = hyp_complete_share(completer_addr, tx, share->completer_prot); break; + case PKVM_ID_GUEST: + ret = guest_complete_share(completer_addr, tx, share->completer_prot); + break; default: ret = -EINVAL; } @@ -1261,6 +1323,44 @@ void hyp_unpin_shared_mem(void *from, void *to) host_unlock_component(); } +int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu) +{ + int ret; + u64 host_addr = hyp_pfn_to_phys(pfn); + u64 guest_addr = hyp_pfn_to_phys(gfn); + struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu); + struct pkvm_mem_share share = { + .tx = { + .nr_pages = 1, + .initiator = { + .id = PKVM_ID_HOST, + .addr = host_addr, + .host = { + .completer_addr = guest_addr, + }, + }, + .completer = { + .id = PKVM_ID_GUEST, + .guest = { + .hyp_vcpu = vcpu, + .phys = host_addr, + }, + }, + }, + .completer_prot = KVM_PGTABLE_PROT_RWX, + }; + + host_lock_component(); + guest_lock_component(vm); + + ret = do_share(&share); + + guest_unlock_component(vm); + host_unlock_component(); + + return ret; +} + static int hyp_zero_page(phys_addr_t phys) { void *addr;