[PATCH 15/17] KVM: arm64: Alloc pkvm_hyp_vm using pKVM heap allocator
Vincent Donnefort
vdonnefort at google.com
Wed May 20 08:26:48 PDT 2026
Transition the allocation of the hypervisor VM state structure
(pkvm_hyp_vm) from the host to the hypervisor using
the new pKVM heap allocator (hyp_alloc()).
Previously, the host was responsible for calculating the size of,
allocating, and donating memory for pkvm_hyp_vm during VM creation. With
the heap allocator in place, the hypervisor now allocates this structure
dynamically at EL2.
Use the pkvm_call_hyp_req() wrapper in the host to invoke
__pkvm_init_vm, which automatically handles any top-up requests if the
hypervisor runs out of heap memory during allocation.
Signed-off-by: Vincent Donnefort <vdonnefort at google.com>
diff --git a/arch/arm64/kvm/hyp/hyp-constants.c b/arch/arm64/kvm/hyp/hyp-constants.c
index b257a3b4bfc5..501ab35a3840 100644
--- a/arch/arm64/kvm/hyp/hyp-constants.c
+++ b/arch/arm64/kvm/hyp/hyp-constants.c
@@ -7,7 +7,6 @@
int main(void)
{
DEFINE(STRUCT_HYP_PAGE_SIZE, sizeof(struct hyp_page));
- DEFINE(PKVM_HYP_VM_SIZE, sizeof(struct pkvm_hyp_vm));
DEFINE(PKVM_HYP_VCPU_SIZE, sizeof(struct pkvm_hyp_vcpu));
return 0;
}
diff --git a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
index 624367d0ef5b..8e930c8729af 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
@@ -82,8 +82,7 @@ void pkvm_hyp_vm_table_init(void *tbl);
int __pkvm_reserve_vm(void);
void __pkvm_unreserve_vm(pkvm_handle_t handle);
-int __pkvm_init_vm(struct kvm *host_kvm, unsigned long vm_hva,
- unsigned long pgd_hva);
+int __pkvm_init_vm(struct kvm *host_kvm, void *pgd);
int __pkvm_init_vcpu(pkvm_handle_t handle, struct kvm_vcpu *host_vcpu,
unsigned long vcpu_hva);
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 4e7db8b48614..ebd6b5c09928 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -556,14 +556,30 @@ static void handle___pkvm_unreserve_vm(struct kvm_cpu_context *host_ctxt)
__pkvm_unreserve_vm(handle);
}
+static void errno_to_smccc(int ret, struct kvm_cpu_context *host_ctxt)
+{
+ struct pkvm_hyp_req req = { .type = PKVM_HYP_NO_REQ };
+
+ switch (ret) {
+ case -ENOMEM:
+ req.type = PKVM_HYP_REQ_HYP_ALLOC;
+ req.mem.nr_pages = hyp_alloc_topup_needed();
+ break;
+ }
+
+ cpu_reg(host_ctxt, 1) = ret;
+ pkvm_hyp_req_to_smccc(host_ctxt, &req);
+}
+
static void handle___pkvm_init_vm(struct kvm_cpu_context *host_ctxt)
{
DECLARE_REG(struct kvm *, host_kvm, host_ctxt, 1);
- DECLARE_REG(unsigned long, vm_hva, host_ctxt, 2);
- DECLARE_REG(unsigned long, pgd_hva, host_ctxt, 3);
+ DECLARE_REG(unsigned long, pgd_hva, host_ctxt, 2);
+ void *pgd;
host_kvm = kern_hyp_va(host_kvm);
- cpu_reg(host_ctxt, 1) = __pkvm_init_vm(host_kvm, vm_hva, pgd_hva);
+ pgd = (void *)kern_hyp_va(pgd_hva);
+ errno_to_smccc(__pkvm_init_vm(host_kvm, pgd), host_ctxt);
}
static void handle___pkvm_init_vcpu(struct kvm_cpu_context *host_ctxt)
diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index 3e7f7606a3da..7405626e103a 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -11,6 +11,7 @@
#include <asm/kvm_emulate.h>
+#include <nvhe/alloc.h>
#include <nvhe/mem_protect.h>
#include <nvhe/memory.h>
#include <nvhe/pkvm.h>
@@ -783,24 +784,22 @@ void teardown_selftest_vm(void)
* Unmap the donated memory from the host at stage 2.
*
* host_kvm: A pointer to the host's struct kvm.
- * vm_hva: The host va of the area being donated for the VM state.
- * Must be page aligned.
- * pgd_hva: The host va of the area being donated for the stage-2 PGD for
- * the VM. Must be page aligned. Its size is implied by the VM's
- * VTCR.
+ * pgd: The va of the area being donated for the stage-2 PGD for the VM. Must
+ * be page aligned. Its size is implied by the VM's VTCR.
*
* Return 0 success, negative error code on failure.
*/
-int __pkvm_init_vm(struct kvm *host_kvm, unsigned long vm_hva,
- unsigned long pgd_hva)
+int __pkvm_init_vm(struct kvm *host_kvm, void *pgd)
{
struct pkvm_hyp_vm *hyp_vm = NULL;
size_t vm_size, pgd_size;
unsigned int nr_vcpus;
pkvm_handle_t handle;
- void *pgd = NULL;
int ret;
+ if (!PAGE_ALIGNED(pgd))
+ return -EINVAL;
+
ret = hyp_pin_shared_mem(host_kvm, host_kvm + 1);
if (ret)
return ret;
@@ -820,15 +819,15 @@ int __pkvm_init_vm(struct kvm *host_kvm, unsigned long vm_hva,
vm_size = pkvm_get_hyp_vm_size(nr_vcpus);
pgd_size = kvm_pgtable_stage2_pgd_size(host_mmu.arch.mmu.vtcr);
- ret = -ENOMEM;
-
- hyp_vm = map_donated_memory(vm_hva, vm_size);
- if (!hyp_vm)
- goto err_remove_mappings;
+ hyp_vm = hyp_alloc(vm_size);
+ if (!hyp_vm) {
+ ret = hyp_alloc_errno();
+ goto err_unpin_kvm;
+ }
- pgd = map_donated_memory_noclear(pgd_hva, pgd_size);
- if (!pgd)
- goto err_remove_mappings;
+ ret = __pkvm_host_donate_hyp(hyp_virt_to_pfn(pgd), PAGE_ALIGN(pgd_size) >> PAGE_SHIFT);
+ if (ret)
+ goto err_free_hyp_vm;
init_pkvm_hyp_vm(host_kvm, hyp_vm, nr_vcpus, handle);
@@ -844,8 +843,9 @@ int __pkvm_init_vm(struct kvm *host_kvm, unsigned long vm_hva,
return 0;
err_remove_mappings:
- unmap_donated_memory(hyp_vm, vm_size);
unmap_donated_memory_noclear(pgd, pgd_size);
+err_free_hyp_vm:
+ hyp_free(hyp_vm);
err_unpin_kvm:
hyp_unpin_shared_mem(host_kvm, host_kvm + 1);
return ret;
@@ -981,7 +981,6 @@ int __pkvm_finalize_teardown_vm(pkvm_handle_t handle)
struct pkvm_hyp_vm *hyp_vm;
struct kvm *host_kvm;
unsigned int idx;
- size_t vm_size;
int err;
hyp_spin_lock(&vm_table_lock);
@@ -1024,8 +1023,7 @@ int __pkvm_finalize_teardown_vm(pkvm_handle_t handle)
teardown_donated_memory(mc, hyp_vcpu, sizeof(*hyp_vcpu));
}
- vm_size = pkvm_get_hyp_vm_size(hyp_vm->kvm.created_vcpus);
- teardown_donated_memory(mc, hyp_vm, vm_size);
+ hyp_free(hyp_vm);
hyp_unpin_shared_mem(host_kvm, host_kvm + 1);
return 0;
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index 15281ae1be39..8fc2e954d382 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -216,8 +216,8 @@ static int __pkvm_create_hyp_vcpu(struct kvm_vcpu *vcpu)
*/
static int __pkvm_create_hyp_vm(struct kvm *kvm)
{
- size_t pgd_sz, hyp_vm_sz;
- void *pgd, *hyp_vm;
+ size_t pgd_sz;
+ void *pgd;
int ret;
if (kvm->created_vcpus < 1)
@@ -234,28 +234,15 @@ static int __pkvm_create_hyp_vm(struct kvm *kvm)
if (!pgd)
return -ENOMEM;
- /* Allocate memory to donate to hyp for vm and vcpu pointers. */
- hyp_vm_sz = PAGE_ALIGN(size_add(PKVM_HYP_VM_SIZE,
- size_mul(sizeof(void *),
- kvm->created_vcpus)));
- hyp_vm = alloc_pages_exact(hyp_vm_sz, GFP_KERNEL_ACCOUNT);
- if (!hyp_vm) {
- ret = -ENOMEM;
- goto free_pgd;
- }
-
- /* Donate the VM memory to hyp and let hyp initialize it. */
- ret = kvm_call_hyp_nvhe(__pkvm_init_vm, kvm, hyp_vm, pgd);
+ ret = pkvm_call_hyp_req(__pkvm_init_vm, kvm, pgd);
if (ret)
- goto free_vm;
+ goto free_pgd;
kvm->arch.pkvm.is_created = true;
init_hyp_stage2_memcache(&kvm->arch.pkvm.stage2_teardown_mc);
kvm_account_pgtable_pages(pgd, pgd_sz / PAGE_SIZE);
return 0;
-free_vm:
- free_pages_exact(hyp_vm, hyp_vm_sz);
free_pgd:
free_pages_exact(pgd, pgd_sz);
return ret;
--
2.54.0.631.ge1b05301d1-goog
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