[PATCH v2 2/3] KVM: arm64: Distinct pKVM teardown memcache for stage-2

From: Vincent Donnefort
Date: Tue Mar 04 2025 - 08:44:48 EST


In order to account for memory dedicated to the stage-2 page-tables, use
a separated memcache when tearing down the VM.

Signed-off-by: Vincent Donnefort <vdonnefort@xxxxxxxxxx>

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 12691ae23d4c..ace3969e8106 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -246,6 +246,7 @@ typedef unsigned int pkvm_handle_t;
struct kvm_protected_vm {
pkvm_handle_t handle;
struct kvm_hyp_memcache teardown_mc;
+ struct kvm_hyp_memcache stage2_teardown_mc;
bool enabled;
};

diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index 3927fe52a3dd..15f8d5315959 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -678,7 +678,7 @@ teardown_donated_memory(struct kvm_hyp_memcache *mc, void *addr, size_t size)

int __pkvm_teardown_vm(pkvm_handle_t handle)
{
- struct kvm_hyp_memcache *mc;
+ struct kvm_hyp_memcache *mc, *stage2_mc;
struct pkvm_hyp_vm *hyp_vm;
struct kvm *host_kvm;
unsigned int idx;
@@ -706,7 +706,8 @@ int __pkvm_teardown_vm(pkvm_handle_t handle)

/* Reclaim guest pages (including page-table pages) */
mc = &host_kvm->arch.pkvm.teardown_mc;
- reclaim_guest_pages(hyp_vm, mc);
+ stage2_mc = &host_kvm->arch.pkvm.stage2_teardown_mc;
+ reclaim_guest_pages(hyp_vm, stage2_mc);
unpin_host_vcpus(hyp_vm->vcpus, hyp_vm->nr_vcpus);

/* Push the metadata pages to the teardown memcache */
@@ -717,7 +718,7 @@ int __pkvm_teardown_vm(pkvm_handle_t handle)
while (vcpu_mc->nr_pages) {
void *addr = pop_hyp_memcache(vcpu_mc, hyp_phys_to_virt);

- push_hyp_memcache(mc, addr, hyp_virt_to_phys);
+ push_hyp_memcache(stage2_mc, addr, hyp_virt_to_phys);
unmap_donated_memory_noclear(addr, PAGE_SIZE);
}

diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index 930b677eb9b0..19921ca407c6 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -111,6 +111,7 @@ static void __pkvm_destroy_hyp_vm(struct kvm *host_kvm)

host_kvm->arch.pkvm.handle = 0;
free_hyp_memcache(&host_kvm->arch.pkvm.teardown_mc);
+ free_hyp_memcache(&host_kvm->arch.pkvm.stage2_teardown_mc);
}

/*
--
2.48.1.711.g2feabab25a-goog