s390/uv: Convert uv_destroy_owned_page() to uv_destroy_(folio|pte)()

Let's have the following variants for destroying pages:

(1) uv_destroy(): Like uv_pin_shared() and uv_convert_from_secure(),
"low level" helper that operates on paddr and doesn't mess with folios.

(2) uv_destroy_folio(): Consumes a folio to which we hold a reference.

(3) uv_destroy_pte(): Consumes a PTE that holds a reference through the
mapping.

Unfortunately we need uv_destroy_pte(), because pfn_folio() and
friends are not available in pgtable.h.

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20240508182955.358628-8-david@redhat.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 70b6ee557eb2246be9d06e76ded170f0a9b974b6..e9eaa4281d94d24261e66bd4684bb24c7ddc29bc 100644 (file)
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1217,7 +1217,7 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
         * The notifier should have destroyed all protected vCPUs at this
         * point, so the destroy should be successful.
         */
-       if (full && !uv_destroy_owned_page(pte_val(res) & PAGE_MASK))
+       if (full && !uv_destroy_pte(res))
                return res;
        /*
         * If something went wrong and the page could not be destroyed, or

diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h
index d2205ff9700725598cd90cdbb170488eff28cb4e..a1bef30066efe944019e0d4bb3bfdffa8aab54b3 100644 (file)
--- a/arch/s390/include/asm/uv.h
+++ b/arch/s390/include/asm/uv.h
@@ -483,7 +483,8 @@ static inline int is_prot_virt_host(void)
 int uv_pin_shared(unsigned long paddr);
 int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb);
 int gmap_destroy_page(struct gmap *gmap, unsigned long gaddr);
-int uv_destroy_owned_page(unsigned long paddr);
+int uv_destroy_folio(struct folio *folio);
+int uv_destroy_pte(pte_t pte);
 int uv_convert_owned_from_secure(unsigned long paddr);
 int gmap_convert_to_secure(struct gmap *gmap, unsigned long gaddr);
 
@@ -497,7 +498,12 @@ static inline int uv_pin_shared(unsigned long paddr)
        return 0;
 }
 
-static inline int uv_destroy_owned_page(unsigned long paddr)
+static inline int uv_destroy_folio(struct folio *folio)
+{
+       return 0;
+}
+
+static inline int uv_destroy_pte(pte_t pte)
 {
        return 0;
 }

diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
index 3d3250b406a6c27a1f3abaaee7900152d5f786aa..61c1ce51c883dbd49f74f7cb27fb25ea0b427da7 100644 (file)
--- a/arch/s390/kernel/uv.c
+++ b/arch/s390/kernel/uv.c
@@ -110,7 +110,7 @@ EXPORT_SYMBOL_GPL(uv_pin_shared);
  *
  * @paddr: Absolute host address of page to be destroyed
  */
-static int uv_destroy_page(unsigned long paddr)
+static int uv_destroy(unsigned long paddr)
 {
        struct uv_cb_cfs uvcb = {
                .header.cmd = UVC_CMD_DESTR_SEC_STOR,
@@ -131,11 +131,10 @@ static int uv_destroy_page(unsigned long paddr)
 }
 
 /*
- * The caller must already hold a reference to the page
+ * The caller must already hold a reference to the folio
  */
-int uv_destroy_owned_page(unsigned long paddr)
+int uv_destroy_folio(struct folio *folio)
 {
-       struct folio *folio = phys_to_folio(paddr);
        int rc;
 
        /* See gmap_make_secure(): large folios cannot be secure */
@@ -143,13 +142,22 @@ int uv_destroy_owned_page(unsigned long paddr)
                return 0;
 
        folio_get(folio);
-       rc = uv_destroy_page(paddr);
+       rc = uv_destroy(folio_to_phys(folio));
        if (!rc)
                clear_bit(PG_arch_1, &folio->flags);
        folio_put(folio);
        return rc;
 }
 
+/*
+ * The present PTE still indirectly holds a folio reference through the mapping.
+ */
+int uv_destroy_pte(pte_t pte)
+{
+       VM_WARN_ON(!pte_present(pte));
+       return uv_destroy_folio(pfn_folio(pte_pfn(pte)));
+}
+
 /*
  * Requests the Ultravisor to encrypt a guest page and make it
  * accessible to the host for paging (export).
@@ -437,6 +445,7 @@ int gmap_destroy_page(struct gmap *gmap, unsigned long gaddr)
 {
        struct vm_area_struct *vma;
        unsigned long uaddr;
+       struct folio *folio;
        struct page *page;
        int rc;
 
@@ -460,7 +469,8 @@ int gmap_destroy_page(struct gmap *gmap, unsigned long gaddr)
        page = follow_page(vma, uaddr, FOLL_WRITE | FOLL_GET);
        if (IS_ERR_OR_NULL(page))
                goto out;
-       rc = uv_destroy_owned_page(page_to_phys(page));
+       folio = page_folio(page);
+       rc = uv_destroy_folio(folio);
        /*
         * Fault handlers can race; it is possible that two CPUs will fault
         * on the same secure page. One CPU can destroy the page, reboot,
@@ -472,7 +482,7 @@ int gmap_destroy_page(struct gmap *gmap, unsigned long gaddr)
         */
        if (rc)
                rc = uv_convert_owned_from_secure(page_to_phys(page));
-       put_page(page);
+       folio_put(folio);
 out:
        mmap_read_unlock(gmap->mm);
        return rc;

diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index 474a25ca5c48ff41935a6ae23eeff29617b877ed..7537e7b4be3930c52e69aaa849dd6dfbbe11bb07 100644 (file)
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -2841,13 +2841,15 @@ static const struct mm_walk_ops gather_pages_ops = {
  */
 void s390_uv_destroy_pfns(unsigned long count, unsigned long *pfns)
 {
+       struct folio *folio;
        unsigned long i;
 
        for (i = 0; i < count; i++) {
+               folio = pfn_folio(pfns[i]);
                /* we always have an extra reference */
-               uv_destroy_owned_page(pfn_to_phys(pfns[i]));
+               uv_destroy_folio(folio);
                /* get rid of the extra reference */
-               put_page(pfn_to_page(pfns[i]));
+               folio_put(folio);
                cond_resched();
        }
 }