From: Keir Fraser <keirf@xxxxxxxxxx>
The VM should only relinquish "normal" pages. For a protected VM, this
means PAGE_OWNED; For a normal VM, this means PAGE_SHARED_BORROWED. All
other page types are rejected and failure is reported to the caller.
Signed-off-by: Keir Fraser <keirf@xxxxxxxxxx>
Signed-off-by: Fuad Tabba <tabba@xxxxxxxxxx>
---
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 45 ++++++++++++++++++++++++---
1 file changed, 41 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 1dd8eee1ab28..405d6e3e17e0 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -321,13 +321,44 @@ void reclaim_guest_pages(struct pkvm_hyp_vm *vm, struct kvm_hyp_memcache *mc)
}
}
+struct relinquish_data {
+ enum pkvm_page_state expected_state;
+ u64 pa;
+};
+
+static int relinquish_walker(const struct kvm_pgtable_visit_ctx *ctx,
+ enum kvm_pgtable_walk_flags visit)
+{
+ kvm_pte_t pte = *ctx->ptep;
+ struct hyp_page *page;
+ struct relinquish_data *data = ctx->arg;
+ enum pkvm_page_state state;
+
+ if (!kvm_pte_valid(pte))
+ return 0;
+
+ state = pkvm_getstate(kvm_pgtable_stage2_pte_prot(pte));
+ if (state != data->expected_state)
+ return -EPERM;
+
+ page = hyp_phys_to_page(kvm_pte_to_phys(pte));
+ if (state == PKVM_PAGE_OWNED)
+ page->flags |= HOST_PAGE_NEED_POISONING;
+ page->flags |= HOST_PAGE_PENDING_RECLAIM;
+
+ data->pa = kvm_pte_to_phys(pte);
+
+ return 0;
+}
+
int __pkvm_guest_relinquish_to_host(struct pkvm_hyp_vcpu *vcpu,
u64 ipa, u64 *ppa)
{
+ struct relinquish_data data;
struct kvm_pgtable_walker walker = {
- .cb = reclaim_walker,
- .arg = ppa,
- .flags = KVM_PGTABLE_WALK_LEAF
+ .cb = relinquish_walker,
+ .flags = KVM_PGTABLE_WALK_LEAF,
+ .arg = &data,
};
struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu);
int ret;
@@ -335,8 +366,13 @@ int __pkvm_guest_relinquish_to_host(struct pkvm_hyp_vcpu *vcpu,
host_lock_component();
guest_lock_component(vm);
+ /* Expected page state depends on VM type. */
+ data.expected_state = pkvm_hyp_vcpu_is_protected(vcpu) ?
+ PKVM_PAGE_OWNED :
+ PKVM_PAGE_SHARED_BORROWED;
+
/* Set default pa value to "not found". */
- *ppa = 0;
+ data.pa = 0;
/* If ipa is mapped: sets page flags, and gets the pa. */
ret = kvm_pgtable_walk(&vm->pgt, ipa, PAGE_SIZE, &walker);
@@ -348,6 +384,7 @@ int __pkvm_guest_relinquish_to_host(struct pkvm_hyp_vcpu *vcpu,
guest_unlock_component(vm);
host_unlock_component();
+ *ppa = data.pa;
return ret;
}
--
2.44.0.rc1.240.g4c46232300-goog
