[v10,5/8] KVM: Migrate kvm_vcpu_map() to kvm_follow_pfn()

Commit Message

David Stevens Feb. 21, 2024, 7:25 a.m. UTC

From: David Stevens <[e-mail]>

Migrate kvm_vcpu_map() to kvm_follow_pfn(). Track is_refcounted_page so
that kvm_vcpu_unmap() know whether or not it needs to release the page.

Signed-off-by: David Stevens <[e-mail]>
---
 include/linux/kvm_host.h |  2 +-
 virt/kvm/kvm_main.c      | 24 ++++++++++++++----------
 2 files changed, 15 insertions(+), 11 deletions(-)

Patch

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 88279649c00d..f72c79f159a2 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -295,6 +295,7 @@  struct kvm_host_map {
 	void *hva;
 	kvm_pfn_t pfn;
 	kvm_pfn_t gfn;
+	bool is_refcounted_page;
 };
 
 /*
@@ -1265,7 +1266,6 @@  void kvm_release_pfn_dirty(kvm_pfn_t pfn);
 void kvm_set_pfn_dirty(kvm_pfn_t pfn);
 void kvm_set_pfn_accessed(kvm_pfn_t pfn);
 
-void kvm_release_pfn(kvm_pfn_t pfn, bool dirty);
 int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
 			int len);
 int kvm_read_guest(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 6c10dc546c8d..e617fe5cac2e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3188,24 +3188,22 @@  struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
 }
 EXPORT_SYMBOL_GPL(gfn_to_page);
 
-void kvm_release_pfn(kvm_pfn_t pfn, bool dirty)
-{
-	if (dirty)
-		kvm_release_pfn_dirty(pfn);
-	else
-		kvm_release_pfn_clean(pfn);
-}
-
 int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map)
 {
 	kvm_pfn_t pfn;
 	void *hva = NULL;
 	struct page *page = KVM_UNMAPPED_PAGE;
+	struct kvm_follow_pfn kfp = {
+		.slot = gfn_to_memslot(vcpu->kvm, gfn),
+		.gfn = gfn,
+		.flags = FOLL_GET | FOLL_WRITE,
+		.allow_non_refcounted_struct_page = true,
+	};
 
 	if (!map)
 		return -EINVAL;
 
-	pfn = gfn_to_pfn(vcpu->kvm, gfn);
+	pfn = kvm_follow_pfn(&kfp);
 	if (is_error_noslot_pfn(pfn))
 		return -EINVAL;
 
@@ -3225,6 +3223,7 @@  int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map)
 	map->hva = hva;
 	map->pfn = pfn;
 	map->gfn = gfn;
+	map->is_refcounted_page = !!kfp.refcounted_page;
 
 	return 0;
 }
@@ -3248,7 +3247,12 @@  void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty)
 	if (dirty)
 		kvm_vcpu_mark_page_dirty(vcpu, map->gfn);
 
-	kvm_release_pfn(map->pfn, dirty);
+	if (map->is_refcounted_page) {
+		if (dirty)
+			kvm_release_page_dirty(map->page);
+		else
+			kvm_release_page_clean(map->page);
+	}
 
 	map->hva = NULL;
 	map->page = NULL;