KVM: arm64: Instantiate pKVM hypervisor VM and vCPU structures from EL1

With the pKVM hypervisor at EL2 now offering hypercalls to the host for
creating and destroying VM and vCPU structures, plumb these in to the
existing arm64 KVM backend to ensure that the hypervisor data structures
are allocated and initialised on first vCPU run for a pKVM guest.

In the host, 'struct kvm_protected_vm' is introduced to hold the handle
of the pKVM VM instance as well as to track references to the memory
donated to the hypervisor so that it can be freed back to the host
allocator following VM teardown. The stage-2 page-table, hypervisor VM
and vCPU structures are allocated separately so as to avoid the need for
a large physically-contiguous allocation in the host at run-time.

Tested-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221110190259.26861-14-will@kernel.org

2 files changed, 14 insertions, 4 deletions

diff --git a/arch/arm64/kvm/hyp/hyp-constants.c b/arch/arm64/kvm/hyp/hyp-constants.c
index b3742a6691e8..b257a3b4bfc5 100644
--- a/arch/arm64/kvm/hyp/hyp-constants.c
+++ b/arch/arm64/kvm/hyp/hyp-constants.c
@@ -2,9 +2,12 @@
 
 #include <linux/kbuild.h>
 #include <nvhe/memory.h>
+#include <nvhe/pkvm.h>
 
 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/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index 135c9a095eca..2c73c4640e4d 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -324,7 +324,7 @@ static pkvm_handle_t insert_vm_table_entry(struct kvm *host_kvm,
 	if (idx < 0)
 		return idx;
 
-	hyp_vm->kvm.arch.pkvm_handle = idx_to_vm_handle(idx);
+	hyp_vm->kvm.arch.pkvm.handle = idx_to_vm_handle(idx);
 
 	/* VMID 0 is reserved for the host */
 	atomic64_set(&mmu->vmid.id, idx + 1);
@@ -333,7 +333,7 @@ static pkvm_handle_t insert_vm_table_entry(struct kvm *host_kvm,
 	mmu->pgt = &hyp_vm->pgt;
 
 	vm_table[idx] = hyp_vm;
-	return hyp_vm->kvm.arch.pkvm_handle;
+	return hyp_vm->kvm.arch.pkvm.handle;
 }
 
 /*
@@ -458,10 +458,10 @@ int __pkvm_init_vm(struct kvm *host_kvm, unsigned long vm_hva,
 		goto err_remove_vm_table_entry;
 	hyp_spin_unlock(&vm_table_lock);
 
-	return hyp_vm->kvm.arch.pkvm_handle;
+	return hyp_vm->kvm.arch.pkvm.handle;
 
 err_remove_vm_table_entry:
-	remove_vm_table_entry(hyp_vm->kvm.arch.pkvm_handle);
+	remove_vm_table_entry(hyp_vm->kvm.arch.pkvm.handle);
 err_unlock:
 	hyp_spin_unlock(&vm_table_lock);
 err_remove_mappings:
@@ -528,6 +528,7 @@ int __pkvm_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;
 
@@ -553,6 +554,12 @@ int __pkvm_teardown_vm(pkvm_handle_t handle)
 	unpin_host_vcpus(hyp_vm->vcpus, hyp_vm->nr_vcpus);
 
 	/* Return the metadata pages to the host */
+	for (idx = 0; idx < hyp_vm->nr_vcpus; ++idx) {
+		struct pkvm_hyp_vcpu *hyp_vcpu = hyp_vm->vcpus[idx];
+
+		unmap_donated_memory(hyp_vcpu, sizeof(*hyp_vcpu));
+	}
+
 	host_kvm = hyp_vm->host_kvm;
 	vm_size = pkvm_get_hyp_vm_size(hyp_vm->kvm.created_vcpus);
 	unmap_donated_memory(hyp_vm, vm_size);