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This will later allow the guest to share a sub-region of an existing huge-mapping with the host. Signed-off-by: Vincent Donnefort --- arch/arm64/include/asm/kvm_asm.h | 1 + arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 1 + arch/arm64/kvm/hyp/nvhe/hyp-main.c | 22 +++ arch/arm64/kvm/hyp/nvhe/mem_protect.c | 127 ++++++++++++++++-- 4 files changed, 138 insertions(+), 13 deletions(-) diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index ec59f0fe9374..a67d171c86d0 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -105,6 +105,7 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___pkvm_host_wrprotect_guest, __KVM_HOST_SMCCC_FUNC___pkvm_host_test_clear_young_guest, __KVM_HOST_SMCCC_FUNC___pkvm_host_mkyoung_guest, + __KVM_HOST_SMCCC_FUNC___pkvm_host_split_guest, __KVM_HOST_SMCCC_FUNC___pkvm_reserve_vm, __KVM_HOST_SMCCC_FUNC___pkvm_unreserve_vm, __KVM_HOST_SMCCC_FUNC___pkvm_init_vm, diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h index 7904a95ab8ac..f9604f9a92dc 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h @@ -50,6 +50,7 @@ int __pkvm_host_relax_perms_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_ int __pkvm_host_wrprotect_guest(u64 gfn, u64 nr_pages, struct pkvm_hyp_vm *hyp_vm); int __pkvm_host_test_clear_young_guest(u64 gfn, u64 nr_pages, bool mkold, struct pkvm_hyp_vm *vm); int __pkvm_host_mkyoung_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu); +int __pkvm_host_split_guest(u64 gfn, u64 nr_pages, 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/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 7ef7da69f48b..cc0e1061d584 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -540,6 +540,27 @@ static void handle___pkvm_host_mkyoung_guest(struct kvm_cpu_context *host_ctxt) cpu_reg(host_ctxt, 1) = ret; } +static void handle___pkvm_host_split_guest(struct kvm_cpu_context *host_ctxt) +{ + DECLARE_REG(u64, gfn, host_ctxt, 1); + DECLARE_REG(u64, nr_pages, host_ctxt, 2); + struct pkvm_hyp_vcpu *hyp_vcpu; + int ret = -EINVAL; + + hyp_vcpu = pkvm_get_loaded_hyp_vcpu(); + if (!hyp_vcpu || !pkvm_hyp_vcpu_is_protected(hyp_vcpu)) + goto out; + + ret = pkvm_refill_memcache(hyp_vcpu); + if (ret) + goto out; + + ret = __pkvm_host_split_guest(gfn, nr_pages, hyp_vcpu); + +out: + cpu_reg(host_ctxt, 1) = ret; +} + static void handle___kvm_adjust_pc(struct kvm_cpu_context *host_ctxt) { DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1); @@ -958,6 +979,7 @@ static const hcall_t host_hcall[] = { HANDLE_FUNC(__pkvm_host_wrprotect_guest), HANDLE_FUNC(__pkvm_host_test_clear_young_guest), HANDLE_FUNC(__pkvm_host_mkyoung_guest), + HANDLE_FUNC(__pkvm_host_split_guest), HANDLE_FUNC(__pkvm_reserve_vm), HANDLE_FUNC(__pkvm_unreserve_vm), HANDLE_FUNC(__pkvm_init_vm), diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 2e8c241f76c9..f4943c2a237f 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -578,6 +578,12 @@ static void __host_update_page_state(phys_addr_t addr, u64 size, enum pkvm_page_ #define KVM_HOST_DONATION_PTE_OWNER_MASK GENMASK(3, 1) #define KVM_HOST_DONATION_PTE_EXTRA_MASK GENMASK(59, 4) +static kvm_pte_t host_stage2_encode_annotation(u8 owner_id, u64 meta) +{ + return FIELD_PREP(KVM_HOST_DONATION_PTE_OWNER_MASK, owner_id) | + FIELD_PREP(KVM_HOST_DONATION_PTE_EXTRA_MASK, meta); +} + static int host_stage2_set_owner_metadata_locked(phys_addr_t addr, u64 size, u8 owner_id, u64 meta) { @@ -596,8 +602,7 @@ static int host_stage2_set_owner_metadata_locked(phys_addr_t addr, u64 size, if (!FIELD_FIT(KVM_HOST_DONATION_PTE_EXTRA_MASK, meta)) return -EINVAL; - annotation = FIELD_PREP(KVM_HOST_DONATION_PTE_OWNER_MASK, owner_id) | - FIELD_PREP(KVM_HOST_DONATION_PTE_EXTRA_MASK, meta); + annotation = host_stage2_encode_annotation(owner_id, meta); ret = host_stage2_try(kvm_pgtable_stage2_annotate, &host_mmu.pgt, addr, size, &host_s2_pool, KVM_HOST_INVALID_PTE_TYPE_DONATION, annotation); @@ -649,10 +654,8 @@ static u64 host_stage2_encode_gfn_meta(struct pkvm_hyp_vm *vm, u64 gfn) FIELD_PREP(KVM_HOST_PTE_OWNER_GUEST_GFN_MASK, gfn); } -static int host_stage2_decode_gfn_meta(kvm_pte_t pte, struct pkvm_hyp_vm **vm, - u64 *gfn) +static int host_stage2_decode_gfn_meta(kvm_pte_t pte, pkvm_handle_t *handle, u64 *gfn) { - pkvm_handle_t handle; u64 meta; if (WARN_ON(kvm_pte_valid(pte))) @@ -667,17 +670,59 @@ static int host_stage2_decode_gfn_meta(kvm_pte_t pte, struct pkvm_hyp_vm **vm, return -EPERM; meta = FIELD_GET(KVM_HOST_DONATION_PTE_EXTRA_MASK, pte); - handle = FIELD_GET(KVM_HOST_PTE_OWNER_GUEST_HANDLE_MASK, meta); - *vm = get_vm_by_handle(handle); - if (!*vm) { - /* We probably raced with teardown; try again */ - return -EAGAIN; - } - + *handle = FIELD_GET(KVM_HOST_PTE_OWNER_GUEST_HANDLE_MASK, meta); *gfn = FIELD_GET(KVM_HOST_PTE_OWNER_GUEST_GFN_MASK, meta); return 0; } +static int host_stage2_split_gfn_meta(phys_addr_t phys, u64 ipa, u64 size, struct pkvm_hyp_vm *vm) +{ + struct kvm_pgtable_mm_ops *mm_ops = &host_mmu.mm_ops; + struct kvm_pgtable *pgt = &host_mmu.pgt; + kvm_pte_t pte, *table, *ptep; + pkvm_handle_t handle; + s8 level; + u64 gfn; + int ret; + + ret = kvm_pgtable_get_leaf(pgt, phys, &pte, &level); + if (ret) + return ret; + + if (kvm_granule_size(level) != size) + return -EINVAL; + + ret = host_stage2_decode_gfn_meta(pte, &handle, &gfn); + if (ret) + return ret; + + if (handle != vm->kvm.arch.pkvm.handle || gfn != (ipa >> PAGE_SHIFT)) + return -EINVAL; + + table = mm_ops->zalloc_page(&host_s2_pool); + if (!table) + return -ENOMEM; + + ptep = table; + while (ptep < table + PTRS_PER_PTE) { + u64 meta = host_stage2_encode_gfn_meta(vm, gfn); + kvm_pte_t annotation = host_stage2_encode_annotation(PKVM_ID_GUEST, meta); + + *ptep = FIELD_PREP(KVM_INVALID_PTE_TYPE_MASK, KVM_HOST_INVALID_PTE_TYPE_DONATION) | + annotation; + + mm_ops->get_page(ptep); + ptep++; + gfn++; + } + + ret = kvm_pgtable_stage2_table_install(pgt, phys, size, table); + if (ret) + kvm_pgtable_stage2_free_unlinked(mm_ops, table, level); + + return ret; +} + static bool host_stage2_force_pte_cb(u64 addr, u64 end, enum kvm_pgtable_prot prot) { /* @@ -1328,6 +1373,7 @@ static int host_stage2_get_guest_info(phys_addr_t phys, u64 *size, struct pkvm_h u64 *gfn) { enum pkvm_page_state state; + pkvm_handle_t handle; kvm_pte_t pte; s8 level; int ret; @@ -1356,10 +1402,16 @@ static int host_stage2_get_guest_info(phys_addr_t phys, u64 *size, struct pkvm_h if (level < KVM_PGTABLE_LAST_LEVEL - 1) return -E2BIG; - ret = host_stage2_decode_gfn_meta(pte, vm, gfn); + ret = host_stage2_decode_gfn_meta(pte, &handle, gfn); if (ret) return ret; + *vm = get_vm_by_handle(handle); + if (!*vm) { + /* We probably raced with teardown; try again */ + return -EAGAIN; + } + *size = kvm_granule_size(level); return 0; @@ -1755,6 +1807,55 @@ int __pkvm_host_mkyoung_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu) return 0; } +int __pkvm_host_split_guest(u64 gfn, u64 nr_pages, struct pkvm_hyp_vcpu *vcpu) +{ + struct kvm_hyp_memcache *mc = &vcpu->vcpu.arch.pkvm_memcache; + struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu); + u64 size = nr_pages << PAGE_SHIFT; + u64 ipa = hyp_pfn_to_phys(gfn); + kvm_pte_t pte, *table; + phys_addr_t phys; + s8 level; + int ret; + + if (!vcpu->vcpu.arch.pkvm_memcache.nr_pages) + return -ENOMEM; + + if (size != PMD_SIZE || !IS_ALIGNED(ipa, PMD_SIZE)) + return -EINVAL; + + level = KVM_PGTABLE_LAST_LEVEL - 1; + + host_lock_component(); + guest_lock_component(vm); + + ret = get_valid_guest_pte(vm, ipa, size, &pte, &phys); + if (ret) + goto unlock; + + table = kvm_pgtable_stage2_create_unlinked(&vm->pgt, kvm_pte_to_phys(pte), level, + kvm_pgtable_stage2_pte_prot(pte), + mc, true); + if (IS_ERR(table)) { + ret = PTR_ERR(table); + goto unlock; + } + + ret = host_stage2_split_gfn_meta(phys, ipa, size, vm); + if (ret) { + kvm_pgtable_stage2_free_unlinked(&vm->mm_ops, table, level); + goto unlock; + } + + WARN_ON(kvm_pgtable_stage2_table_install(&vm->pgt, ipa, size, table)); + +unlock: + guest_unlock_component(vm); + host_unlock_component(); + + return ret; +} + #ifdef CONFIG_NVHE_EL2_DEBUG struct pkvm_expected_state { enum pkvm_page_state host; -- 2.55.0.1007.g17ff1f9808-goog