From f28f1d02f4eaac05c2ad6bf7264a8696dc21d011 Mon Sep 17 00:00:00 2001 From: Vincent Donnefort Date: Wed, 21 May 2025 13:48:28 +0100 Subject: [PATCH] KVM: arm64: Add a range to __pkvm_host_unshare_guest() In preparation for supporting stage-2 huge mappings for np-guest. Add a nr_pages argument to the __pkvm_host_unshare_guest hypercall. This range supports only two values: 1 or PMD_SIZE / PAGE_SIZE (that is 512 on a 4K-pages system). Signed-off-by: Vincent Donnefort Link: https://lore.kernel.org/r/20250521124834.1070650-5-vdonnefort@google.com Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 2 +- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 3 +- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 57 ++++++++++--------- arch/arm64/kvm/pkvm.c | 2 +- 4 files changed, 35 insertions(+), 29 deletions(-) diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h index 47aa7b01114f..19671edbe18f 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h @@ -41,7 +41,7 @@ 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, u64 nr_pages, struct pkvm_hyp_vcpu *vcpu, enum kvm_pgtable_prot prot); -int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm); +int __pkvm_host_unshare_guest(u64 gfn, u64 nr_pages, struct pkvm_hyp_vm *hyp_vm); int __pkvm_host_relax_perms_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_pgtable_prot prot); int __pkvm_host_wrprotect_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm); int __pkvm_host_test_clear_young_guest(u64 gfn, bool mkold, struct pkvm_hyp_vm *vm); diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 4d3d215955c3..5c03bd1db873 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -270,6 +270,7 @@ 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); + DECLARE_REG(u64, nr_pages, host_ctxt, 3); struct pkvm_hyp_vm *hyp_vm; int ret = -EINVAL; @@ -280,7 +281,7 @@ static void handle___pkvm_host_unshare_guest(struct kvm_cpu_context *host_ctxt) if (!hyp_vm) goto out; - ret = __pkvm_host_unshare_guest(gfn, hyp_vm); + ret = __pkvm_host_unshare_guest(gfn, nr_pages, hyp_vm); put_pkvm_hyp_vm(hyp_vm); out: cpu_reg(host_ctxt, 1) = ret; diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 8e0847aa090d..884e2316aa48 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -980,10 +980,9 @@ unlock: return ret; } -static int __check_host_shared_guest(struct pkvm_hyp_vm *vm, u64 *__phys, u64 ipa) +static int __check_host_shared_guest(struct pkvm_hyp_vm *vm, u64 *__phys, u64 ipa, u64 size) { enum pkvm_page_state state; - struct hyp_page *page; kvm_pte_t pte; u64 phys; s8 level; @@ -994,7 +993,7 @@ static int __check_host_shared_guest(struct pkvm_hyp_vm *vm, u64 *__phys, u64 ip return ret; if (!kvm_pte_valid(pte)) return -ENOENT; - if (level != KVM_PGTABLE_LAST_LEVEL) + if (kvm_granule_size(level) != size) return -E2BIG; state = guest_get_page_state(pte, ipa); @@ -1002,43 +1001,49 @@ static int __check_host_shared_guest(struct pkvm_hyp_vm *vm, u64 *__phys, u64 ip return -EPERM; phys = kvm_pte_to_phys(pte); - ret = check_range_allowed_memory(phys, phys + PAGE_SIZE); + ret = check_range_allowed_memory(phys, phys + size); if (WARN_ON(ret)) return ret; - page = hyp_phys_to_page(phys); - if (get_host_state(page) != PKVM_PAGE_SHARED_OWNED) - return -EPERM; - if (WARN_ON(!page->host_share_guest_count)) - return -EINVAL; + for_each_hyp_page(page, phys, size) { + if (get_host_state(page) != PKVM_PAGE_SHARED_OWNED) + return -EPERM; + if (WARN_ON(!page->host_share_guest_count)) + return -EINVAL; + } *__phys = phys; return 0; } -int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *vm) +int __pkvm_host_unshare_guest(u64 gfn, u64 nr_pages, struct pkvm_hyp_vm *vm) { u64 ipa = hyp_pfn_to_phys(gfn); - struct hyp_page *page; - u64 phys; + u64 size, phys; int ret; + ret = __guest_check_transition_size(0, ipa, nr_pages, &size); + if (ret) + return ret; + host_lock_component(); guest_lock_component(vm); - ret = __check_host_shared_guest(vm, &phys, ipa); + ret = __check_host_shared_guest(vm, &phys, ipa, size); if (ret) goto unlock; - ret = kvm_pgtable_stage2_unmap(&vm->pgt, ipa, PAGE_SIZE); + ret = kvm_pgtable_stage2_unmap(&vm->pgt, ipa, size); if (ret) goto unlock; - page = 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)); + for_each_hyp_page(page, phys, size) { + /* __check_host_shared_guest() protects against underflow */ + page->host_share_guest_count--; + if (!page->host_share_guest_count) + set_host_state(page, PKVM_PAGE_OWNED); + } unlock: guest_unlock_component(vm); @@ -1058,7 +1063,7 @@ static void assert_host_shared_guest(struct pkvm_hyp_vm *vm, u64 ipa) host_lock_component(); guest_lock_component(vm); - ret = __check_host_shared_guest(vm, &phys, ipa); + ret = __check_host_shared_guest(vm, &phys, ipa, PAGE_SIZE); guest_unlock_component(vm); host_unlock_component(); @@ -1245,7 +1250,7 @@ void pkvm_ownership_selftest(void *base) assert_transition_res(-EPERM, __pkvm_host_unshare_ffa, pfn, 1); assert_transition_res(-EPERM, hyp_pin_shared_mem, virt, virt + size); assert_transition_res(-EPERM, __pkvm_host_share_guest, pfn, gfn, 1, vcpu, prot); - assert_transition_res(-ENOENT, __pkvm_host_unshare_guest, gfn, vm); + assert_transition_res(-ENOENT, __pkvm_host_unshare_guest, gfn, 1, vm); selftest_state.host = PKVM_PAGE_OWNED; selftest_state.hyp = PKVM_NOPAGE; @@ -1253,7 +1258,7 @@ void pkvm_ownership_selftest(void *base) assert_transition_res(-EPERM, __pkvm_hyp_donate_host, pfn, 1); assert_transition_res(-EPERM, __pkvm_host_unshare_hyp, pfn); assert_transition_res(-EPERM, __pkvm_host_unshare_ffa, pfn, 1); - assert_transition_res(-ENOENT, __pkvm_host_unshare_guest, gfn, vm); + assert_transition_res(-ENOENT, __pkvm_host_unshare_guest, gfn, 1, vm); assert_transition_res(-EPERM, hyp_pin_shared_mem, virt, virt + size); selftest_state.host = PKVM_PAGE_SHARED_OWNED; @@ -1264,7 +1269,7 @@ void pkvm_ownership_selftest(void *base) assert_transition_res(-EPERM, __pkvm_host_share_ffa, pfn, 1); assert_transition_res(-EPERM, __pkvm_hyp_donate_host, pfn, 1); assert_transition_res(-EPERM, __pkvm_host_share_guest, pfn, gfn, 1, vcpu, prot); - assert_transition_res(-ENOENT, __pkvm_host_unshare_guest, gfn, vm); + assert_transition_res(-ENOENT, __pkvm_host_unshare_guest, gfn, 1, vm); assert_transition_res(0, hyp_pin_shared_mem, virt, virt + size); assert_transition_res(0, hyp_pin_shared_mem, virt, virt + size); @@ -1276,7 +1281,7 @@ void pkvm_ownership_selftest(void *base) assert_transition_res(-EPERM, __pkvm_host_share_ffa, pfn, 1); assert_transition_res(-EPERM, __pkvm_hyp_donate_host, pfn, 1); assert_transition_res(-EPERM, __pkvm_host_share_guest, pfn, gfn, 1, vcpu, prot); - assert_transition_res(-ENOENT, __pkvm_host_unshare_guest, gfn, vm); + assert_transition_res(-ENOENT, __pkvm_host_unshare_guest, gfn, 1, vm); hyp_unpin_shared_mem(virt, virt + size); assert_page_state(); @@ -1295,7 +1300,7 @@ void pkvm_ownership_selftest(void *base) assert_transition_res(-EPERM, __pkvm_host_unshare_hyp, pfn); assert_transition_res(-EPERM, __pkvm_hyp_donate_host, pfn, 1); assert_transition_res(-EPERM, __pkvm_host_share_guest, pfn, gfn, 1, vcpu, prot); - assert_transition_res(-ENOENT, __pkvm_host_unshare_guest, gfn, vm); + assert_transition_res(-ENOENT, __pkvm_host_unshare_guest, gfn, 1, vm); assert_transition_res(-EPERM, hyp_pin_shared_mem, virt, virt + size); selftest_state.host = PKVM_PAGE_OWNED; @@ -1319,11 +1324,11 @@ void pkvm_ownership_selftest(void *base) WARN_ON(hyp_virt_to_page(virt)->host_share_guest_count != 2); selftest_state.guest[0] = PKVM_NOPAGE; - assert_transition_res(0, __pkvm_host_unshare_guest, gfn, vm); + assert_transition_res(0, __pkvm_host_unshare_guest, gfn, 1, vm); selftest_state.guest[1] = PKVM_NOPAGE; selftest_state.host = PKVM_PAGE_OWNED; - assert_transition_res(0, __pkvm_host_unshare_guest, gfn + 1, vm); + assert_transition_res(0, __pkvm_host_unshare_guest, gfn + 1, 1, vm); selftest_state.host = PKVM_NOPAGE; selftest_state.hyp = PKVM_PAGE_OWNED; diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c index 987bc5fb18f9..0c5733be6bf4 100644 --- a/arch/arm64/kvm/pkvm.c +++ b/arch/arm64/kvm/pkvm.c @@ -390,7 +390,7 @@ int pkvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size) lockdep_assert_held_write(&kvm->mmu_lock); for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping) { - ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_guest, handle, mapping->gfn); + ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_guest, handle, mapping->gfn, 1); if (WARN_ON(ret)) break; rb_erase(&mapping->node, &pgt->pkvm_mappings); -- 2.25.1