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Signed-off-by: Quentin Perret --- arch/arm64/include/asm/kvm_asm.h | 1 + arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 1 + arch/arm64/kvm/hyp/include/nvhe/pkvm.h | 5 ++ arch/arm64/kvm/hyp/nvhe/hyp-main.c | 24 ++++++ arch/arm64/kvm/hyp/nvhe/mem_protect.c | 78 +++++++++++++++++++ 5 files changed, 109 insertions(+) diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_= asm.h index b69390108c5a..e67efee936b6 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -66,6 +66,7 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___pkvm_host_share_hyp, __KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_hyp, __KVM_HOST_SMCCC_FUNC___pkvm_host_share_guest, + __KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_guest, __KVM_HOST_SMCCC_FUNC___kvm_adjust_pc, __KVM_HOST_SMCCC_FUNC___kvm_vcpu_run, __KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context, diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm= /hyp/include/nvhe/mem_protect.h index a7976e50f556..e528a42ed60e 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h @@ -40,6 +40,7 @@ int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages); int __pkvm_host_share_ffa(u64 pfn, u64 nr_pages); int __pkvm_host_unshare_ffa(u64 pfn, u64 nr_pages); int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu, = enum kvm_pgtable_prot prot); +int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm); =20 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/include/nvhe/pkvm.h b/arch/arm64/kvm/hyp/in= clude/nvhe/pkvm.h index be52c5b15e21..5dfc9ece9aa5 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h +++ b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h @@ -64,6 +64,11 @@ static inline bool pkvm_hyp_vcpu_is_protected(struct pkv= m_hyp_vcpu *hyp_vcpu) return vcpu_is_protected(&hyp_vcpu->vcpu); } =20 +static inline bool pkvm_hyp_vm_is_protected(struct pkvm_hyp_vm *hyp_vm) +{ + return kvm_vm_is_protected(&hyp_vm->kvm); +} + void pkvm_hyp_vm_table_init(void *tbl); =20 int __pkvm_init_vm(struct kvm *host_kvm, unsigned long vm_hva, diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/h= yp-main.c index 32bdf6b27958..68bbef69d99a 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -242,6 +242,29 @@ static void handle___pkvm_host_share_guest(struct kvm_= cpu_context *host_ctxt) cpu_reg(host_ctxt, 1) =3D ret; } =20 +static void handle___pkvm_host_unshare_guest(struct kvm_cpu_context *host_= ctxt) +{ + DECLARE_REG(pkvm_handle_t, handle, host_ctxt, 1); + DECLARE_REG(u64, gfn, host_ctxt, 2); + struct pkvm_hyp_vm *hyp_vm; + int ret =3D -EINVAL; + + if (!is_protected_kvm_enabled()) + goto out; + + hyp_vm =3D get_pkvm_hyp_vm(handle); + if (!hyp_vm) + goto out; + if (pkvm_hyp_vm_is_protected(hyp_vm)) + goto put_hyp_vm; + + ret =3D __pkvm_host_unshare_guest(gfn, hyp_vm); +put_hyp_vm: + put_pkvm_hyp_vm(hyp_vm); +out: + cpu_reg(host_ctxt, 1) =3D ret; +} + static void handle___kvm_adjust_pc(struct kvm_cpu_context *host_ctxt) { DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1); @@ -459,6 +482,7 @@ static const hcall_t host_hcall[] =3D { HANDLE_FUNC(__pkvm_host_share_hyp), HANDLE_FUNC(__pkvm_host_unshare_hyp), HANDLE_FUNC(__pkvm_host_share_guest), + HANDLE_FUNC(__pkvm_host_unshare_guest), HANDLE_FUNC(__kvm_adjust_pc), HANDLE_FUNC(__kvm_vcpu_run), HANDLE_FUNC(__kvm_flush_vm_context), diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvh= e/mem_protect.c index a69d7212b64c..f7476a29e1a9 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -1413,3 +1413,81 @@ int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct= pkvm_hyp_vcpu *vcpu, =20 return ret; } + +static int guest_get_valid_pte(struct pkvm_hyp_vm *vm, u64 *phys, u64 ipa,= u8 order, kvm_pte_t *pte) +{ + size_t size =3D PAGE_SIZE << order; + s8 level; + + if (order && size !=3D PMD_SIZE) + return -EINVAL; + + WARN_ON(kvm_pgtable_get_leaf(&vm->pgt, ipa, pte, &level)); + + if (kvm_granule_size(level) !=3D size) + return -E2BIG; + + if (!kvm_pte_valid(*pte)) + return -ENOENT; + + *phys =3D kvm_pte_to_phys(*pte); + + return 0; +} + +static int __check_host_unshare_guest(struct pkvm_hyp_vm *vm, u64 *phys, u= 64 ipa) +{ + enum pkvm_page_state state; + struct hyp_page *page; + kvm_pte_t pte; + int ret; + + ret =3D guest_get_valid_pte(vm, phys, ipa, 0, &pte); + if (ret) + return ret; + + state =3D guest_get_page_state(pte, ipa); + if (state !=3D PKVM_PAGE_SHARED_BORROWED) + return -EPERM; + + ret =3D range_is_allowed_memory(*phys, *phys + PAGE_SIZE); + if (ret) + return ret; + + page =3D hyp_phys_to_page(*phys); + if (page->host_state !=3D PKVM_PAGE_SHARED_OWNED) + return -EPERM; + WARN_ON(!page->host_share_guest_count); + + return 0; +} + +int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm) +{ + u64 ipa =3D hyp_pfn_to_phys(gfn); + struct hyp_page *page; + u64 phys; + int ret; + + host_lock_component(); + guest_lock_component(hyp_vm); + + ret =3D __check_host_unshare_guest(hyp_vm, &phys, ipa); + if (ret) + goto unlock; + + ret =3D kvm_pgtable_stage2_unmap(&hyp_vm->pgt, ipa, PAGE_SIZE); + if (ret) + goto unlock; + + page =3D hyp_phys_to_page(phys); + page->host_share_guest_count--; + if (!page->host_share_guest_count) + WARN_ON(__host_set_page_state_range(phys, PAGE_SIZE, PKVM_PAGE_OWNED)); + +unlock: + guest_unlock_component(hyp_vm); + host_unlock_component(); + + return ret; +} --=20 2.47.0.163.g1226f6d8fa-goog