[PATCH v1 4/4] KVM: s390: vsie: stop using "struct page" for vsie page

David Hildenbrand
2025-01-07T15:43:58Z

Now that we no longer use page->index and the page refcount explicitly,
let's avoid messing with "struct page" completely.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/s390/include/asm/kvm_host.h | 4 +++-
arch/s390/kvm/vsie.c | 31 ++++++++++++-------------------
2 files changed, 15 insertions(+), 20 deletions(-)

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 97c7c81275434..4581388411b71 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -931,12 +931,14 @@ struct sie_page2 {
u8 reserved928[0x1000 - 0x928]; /* 0x0928 */
};

+struct vsie_page;
+
struct kvm_s390_vsie {
struct mutex mutex;
struct radix_tree_root addr_to_page;
int page_count;
int next;
- struct page *pages[KVM_MAX_VCPUS];
+ struct vsie_page *pages[KVM_MAX_VCPUS];
};

struct kvm_s390_gisa_iam {
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index 29fdffeab635d..22643f4ae4455 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -599,7 +599,6 @@ void kvm_s390_vsie_gmap_notifier(struct gmap *gmap, unsigned long start,
struct kvm *kvm = gmap->private;
struct vsie_page *cur;
unsigned long prefix;
- struct page *page;
int i;

if (!gmap_is_shadow(gmap))
@@ -609,10 +608,9 @@ void kvm_s390_vsie_gmap_notifier(struct gmap *gmap, unsigned long start,
* therefore we can safely reference them all the time.
*/
for (i = 0; i < kvm->arch.vsie.page_count; i++) {
- page = READ_ONCE(kvm->arch.vsie.pages[i]);
- if (!page)
+ cur = READ_ONCE(kvm->arch.vsie.pages[i]);
+ if (!cur)
continue;
- cur = page_to_virt(page);
if (READ_ONCE(cur->gmap) != gmap)
continue;
prefix = cur->scb_s.prefix << GUEST_PREFIX_SHIFT;
@@ -1384,14 +1382,12 @@ static void put_vsie_page(struct vsie_page *vsie_page)
static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr)
{
struct vsie_page *vsie_page;
- struct page *page;
int nr_vcpus;

rcu_read_lock();
- page = radix_tree_lookup(&kvm->arch.vsie.addr_to_page, addr >> 9);
+ vsie_page = radix_tree_lookup(&kvm->arch.vsie.addr_to_page, addr >> 9);
rcu_read_unlock();
- if (page) {
- vsie_page = page_to_virt(page);
+ if (vsie_page) {
if (try_get_vsie_page(vsie_page)) {
if (vsie_page->scb_gpa == addr)
return vsie_page;
@@ -1411,20 +1407,18 @@ static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr)

mutex_lock(&kvm->arch.vsie.mutex);
if (kvm->arch.vsie.page_count < nr_vcpus) {
- page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO | GFP_DMA);
- if (!page) {
+ vsie_page = (void *)__get_free_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO | GFP_DMA);
+ if (!vsie_page) {
mutex_unlock(&kvm->arch.vsie.mutex);
return ERR_PTR(-ENOMEM);
}
- vsie_page = page_to_virt(page);
__set_bit(VSIE_PAGE_IN_USE, &vsie_page->flags);
- kvm->arch.vsie.pages[kvm->arch.vsie.page_count] = page;
+ kvm->arch.vsie.pages[kvm->arch.vsie.page_count] = vsie_page;
kvm->arch.vsie.page_count++;
} else {
/* reuse an existing entry that belongs to nobody */
while (true) {
- page = kvm->arch.vsie.pages[kvm->arch.vsie.next];
- vsie_page = page_to_virt(page);
+ vsie_page = kvm->arch.vsie.pages[kvm->arch.vsie.next];
if (try_get_vsie_page(vsie_page))
break;
kvm->arch.vsie.next++;
@@ -1438,7 +1432,8 @@ static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr)
vsie_page->scb_gpa = ULONG_MAX;

/* Double use of the same address or allocation failure. */
- if (radix_tree_insert(&kvm->arch.vsie.addr_to_page, addr >> 9, page)) {
+ if (radix_tree_insert(&kvm->arch.vsie.addr_to_page, addr >> 9,
+ vsie_page)) {
put_vsie_page(vsie_page);
mutex_unlock(&kvm->arch.vsie.mutex);
return NULL;
@@ -1519,20 +1514,18 @@ void kvm_s390_vsie_init(struct kvm *kvm)
void kvm_s390_vsie_destroy(struct kvm *kvm)
{
struct vsie_page *vsie_page;
- struct page *page;
int i;

mutex_lock(&kvm->arch.vsie.mutex);
for (i = 0; i < kvm->arch.vsie.page_count; i++) {
- page = kvm->arch.vsie.pages[i];
+ vsie_page = kvm->arch.vsie.pages[i];
kvm->arch.vsie.pages[i] = NULL;
- vsie_page = page_to_virt(page);
release_gmap_shadow(vsie_page);
/* free the radix tree entry */
if (vsie_page->scb_gpa != ULONG_MAX)
radix_tree_delete(&kvm->arch.vsie.addr_to_page,
vsie_page->scb_gpa >> 9);
- __free_page(page);
+ free_page((unsigned long)vsie_page);
}
kvm->arch.vsie.page_count = 0;
mutex_unlock(&kvm->arch.vsie.mutex);
--
2.47.1