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KVM: arm64: Add a range to __pkvm_host_unshare_guest()

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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@google.com>
Link: https://lore.kernel.org/r/20250521124834.1070650-5-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Vincent Donnefort
2025-05-21 13:48:28 +01:00
committed by Marc Zyngier
parent 4274385ebf
commit f28f1d02f4
4 changed files with 35 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
View File

@@ -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);

3
arch/arm64/kvm/hyp/nvhe/hyp-main.c
View File

@@ -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;

57
arch/arm64/kvm/hyp/nvhe/mem_protect.c
View File

@@ -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;

2
arch/arm64/kvm/pkvm.c
View File

@@ -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);