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Message-ID: <20250509131706.2336138-5-vdonnefort@google.com>
Date: Fri, 9 May 2025 14:17:00 +0100
From: Vincent Donnefort <vdonnefort@...gle.com>
To: maz@...nel.org, oliver.upton@...ux.dev, joey.gouly@....com,
suzuki.poulose@....com, yuzenghui@...wei.com, catalin.marinas@....com,
will@...nel.org
Cc: qperret@...gle.com, linux-arm-kernel@...ts.infradead.org,
kvmarm@...ts.linux.dev, linux-kernel@...r.kernel.org, kernel-team@...roid.com,
Vincent Donnefort <vdonnefort@...gle.com>
Subject: [PATCH v4 04/10] 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 <vdonnefort@...gle.com>
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 f0f7c6f83e57..ae9a91a21a61 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -990,7 +990,7 @@ int __pkvm_host_share_guest(u64 pfn, u64 gfn, u64 nr_pages, struct pkvm_hyp_vcpu
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;
@@ -1004,7 +1004,7 @@ 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);
@@ -1012,43 +1012,50 @@ 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(phys, size, page) {
+ 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(phys, size, page) {
+ /* __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);
@@ -1068,7 +1075,7 @@ 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();
@@ -1255,7 +1262,7 @@ 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;
@@ -1263,7 +1270,7 @@ 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;
@@ -1274,7 +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);
assert_transition_res(0, hyp_pin_shared_mem, virt, virt + size);
assert_transition_res(0, hyp_pin_shared_mem, virt, virt + size);
@@ -1286,7 +1293,7 @@ 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();
@@ -1305,7 +1312,7 @@ 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;
@@ -1329,11 +1336,11 @@ 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 0285e2cd2e7f..f77c5157a8d7 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -371,7 +371,7 @@ 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);
--
2.49.0.1015.ga840276032-goog
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