[PATCH 1/2] s390: Convert gmap code to use ptdesc

Matthew Wilcox (Oracle)
2024-12-19T16:22:58Z

There was originally some doubt about whether these page tables
should be represented by a vanilla struct page or whether they
should be a ptdesc. As we continue on our quest to shrink
struct page, we seem to have crossed the line into believing that
thse page tables should be a ptdesc. At least for now.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
arch/s390/mm/gmap.c | 181 ++++++++++++++++++++++----------------------
1 file changed, 89 insertions(+), 92 deletions(-)

diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index 16b8a36c56de..2ca100aae1f7 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -26,15 +26,15 @@

#define GMAP_SHADOW_FAKE_TABLE 1ULL

-static struct page *gmap_alloc_crst(void)
+static struct ptdesc *gmap_alloc_crst(void)
{
- struct page *page;
+ struct ptdesc *ptdesc;

- page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
- if (!page)
+ ptdesc = pagetable_alloc(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
+ if (!ptdesc)
return NULL;
- __arch_set_page_dat(page_to_virt(page), 1UL << CRST_ALLOC_ORDER);
- return page;
+ __arch_set_page_dat(ptdesc_to_virt(ptdesc), 1UL << CRST_ALLOC_ORDER);
+ return ptdesc;
}

/**
@@ -46,7 +46,7 @@ static struct page *gmap_alloc_crst(void)
static struct gmap *gmap_alloc(unsigned long limit)
{
struct gmap *gmap;
- struct page *page;
+ struct ptdesc *ptdesc;
unsigned long *table;
unsigned long etype, atype;

@@ -79,12 +79,12 @@ static struct gmap *gmap_alloc(unsigned long limit)
spin_lock_init(&gmap->guest_table_lock);
spin_lock_init(&gmap->shadow_lock);
refcount_set(&gmap->ref_count, 1);
- page = gmap_alloc_crst();
- if (!page)
+ ptdesc = gmap_alloc_crst();
+ if (!ptdesc)
goto out_free;
- page->index = 0;
- list_add(&page->lru, &gmap->crst_list);
- table = page_to_virt(page);
+ ptdesc->pt_index = 0;
+ list_add(&ptdesc->pt_list, &gmap->crst_list);
+ table = ptdesc_to_virt(ptdesc);
crst_table_init(table, etype);
gmap->table = table;
gmap->asce = atype | _ASCE_TABLE_LENGTH |
@@ -193,23 +193,21 @@ static void gmap_rmap_radix_tree_free(struct radix_tree_root *root)
*/
static void gmap_free(struct gmap *gmap)
{
- struct page *page, *next;
+ struct ptdesc *ptdesc, *next;

/* Flush tlb of all gmaps (if not already done for shadows) */
if (!(gmap_is_shadow(gmap) && gmap->removed))
gmap_flush_tlb(gmap);
/* Free all segment & region tables. */
- list_for_each_entry_safe(page, next, &gmap->crst_list, lru)
- __free_pages(page, CRST_ALLOC_ORDER);
+ list_for_each_entry_safe(ptdesc, next, &gmap->crst_list, pt_list)
+ pagetable_free(ptdesc);
gmap_radix_tree_free(&gmap->guest_to_host);
gmap_radix_tree_free(&gmap->host_to_guest);

/* Free additional data for a shadow gmap */
if (gmap_is_shadow(gmap)) {
- struct ptdesc *ptdesc, *n;
-
/* Free all page tables. */
- list_for_each_entry_safe(ptdesc, n, &gmap->pt_list, pt_list)
+ list_for_each_entry_safe(ptdesc, next, &gmap->pt_list, pt_list)
page_table_free_pgste(ptdesc);
gmap_rmap_radix_tree_free(&gmap->host_to_rmap);
/* Release reference to the parent */
@@ -287,26 +285,26 @@ EXPORT_SYMBOL_GPL(gmap_remove);
static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
unsigned long init, unsigned long gaddr)
{
- struct page *page;
+ struct ptdesc *ptdesc;
unsigned long *new;

/* since we dont free the gmap table until gmap_free we can unlock */
- page = gmap_alloc_crst();
- if (!page)
+ ptdesc = gmap_alloc_crst();
+ if (!ptdesc)
return -ENOMEM;
- new = page_to_virt(page);
+ new = ptdesc_to_virt(ptdesc);
crst_table_init(new, init);
spin_lock(&gmap->guest_table_lock);
if (*table & _REGION_ENTRY_INVALID) {
- list_add(&page->lru, &gmap->crst_list);
+ list_add(&ptdesc->pt_list, &gmap->crst_list);
*table = __pa(new) | _REGION_ENTRY_LENGTH |
(*table & _REGION_ENTRY_TYPE_MASK);
- page->index = gaddr;
- page = NULL;
+ ptdesc->pt_index = gaddr;
+ ptdesc = NULL;
}
spin_unlock(&gmap->guest_table_lock);
- if (page)
- __free_pages(page, CRST_ALLOC_ORDER);
+ if (ptdesc)
+ pagetable_free(ptdesc);
return 0;
}

@@ -318,13 +316,13 @@ static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
*/
static unsigned long __gmap_segment_gaddr(unsigned long *entry)
{
- struct page *page;
+ struct ptdesc *ptdesc;
unsigned long offset;

offset = (unsigned long) entry / sizeof(unsigned long);
offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
- page = pmd_pgtable_page((pmd_t *) entry);
- return page->index + offset;
+ ptdesc = pmd_ptdesc((pmd_t *) entry);
+ return ptdesc->pt_index + offset;
}

/**
@@ -1458,7 +1456,7 @@ static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr)
{
unsigned long r3o, *r3e;
phys_addr_t sgt;
- struct page *page;
+ struct ptdesc *ptdesc;

BUG_ON(!gmap_is_shadow(sg));
r3e = gmap_table_walk(sg, raddr, 2); /* get region-3 pointer */
@@ -1471,9 +1469,9 @@ static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr)
*r3e = _REGION3_ENTRY_EMPTY;
__gmap_unshadow_sgt(sg, raddr, __va(sgt));
/* Free segment table */
- page = phys_to_page(sgt);
- list_del(&page->lru);
- __free_pages(page, CRST_ALLOC_ORDER);
+ ptdesc = page_ptdesc(phys_to_page(sgt));
+ list_del(&ptdesc->pt_list);
+ pagetable_free(ptdesc);
}

/**
@@ -1487,7 +1485,7 @@ static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr)
static void __gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr,
unsigned long *r3t)
{
- struct page *page;
+ struct ptdesc *ptdesc;
phys_addr_t sgt;
int i;

@@ -1499,9 +1497,9 @@ static void __gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr,
r3t[i] = _REGION3_ENTRY_EMPTY;
__gmap_unshadow_sgt(sg, raddr, __va(sgt));
/* Free segment table */
- page = phys_to_page(sgt);
- list_del(&page->lru);
- __free_pages(page, CRST_ALLOC_ORDER);
+ ptdesc = page_ptdesc(phys_to_page(sgt));
+ list_del(&ptdesc->pt_list);
+ pagetable_free(ptdesc);
}
}

@@ -1516,7 +1514,7 @@ static void gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr)
{
unsigned long r2o, *r2e;
phys_addr_t r3t;
- struct page *page;
+ struct ptdesc *ptdesc;

BUG_ON(!gmap_is_shadow(sg));
r2e = gmap_table_walk(sg, raddr, 3); /* get region-2 pointer */
@@ -1529,9 +1527,9 @@ static void gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr)
*r2e = _REGION2_ENTRY_EMPTY;
__gmap_unshadow_r3t(sg, raddr, __va(r3t));
/* Free region 3 table */
- page = phys_to_page(r3t);
- list_del(&page->lru);
- __free_pages(page, CRST_ALLOC_ORDER);
+ ptdesc = page_ptdesc(phys_to_page(r3t));
+ list_del(&ptdesc->pt_list);
+ pagetable_free(ptdesc);
}

/**
@@ -1546,7 +1544,7 @@ static void __gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr,
unsigned long *r2t)
{
phys_addr_t r3t;
- struct page *page;
+ struct ptdesc *ptdesc;
int i;

BUG_ON(!gmap_is_shadow(sg));
@@ -1557,9 +1555,9 @@ static void __gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr,
r2t[i] = _REGION2_ENTRY_EMPTY;
__gmap_unshadow_r3t(sg, raddr, __va(r3t));
/* Free region 3 table */
- page = phys_to_page(r3t);
- list_del(&page->lru);
- __free_pages(page, CRST_ALLOC_ORDER);
+ ptdesc = page_ptdesc(phys_to_page(r3t));
+ list_del(&ptdesc->pt_list);
+ pagetable_free(ptdesc);
}
}

@@ -1573,7 +1571,7 @@ static void __gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr,
static void gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr)
{
unsigned long r1o, *r1e;
- struct page *page;
+ struct ptdesc *ptdesc;
phys_addr_t r2t;

BUG_ON(!gmap_is_shadow(sg));
@@ -1587,9 +1585,9 @@ static void gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr)
*r1e = _REGION1_ENTRY_EMPTY;
__gmap_unshadow_r2t(sg, raddr, __va(r2t));
/* Free region 2 table */
- page = phys_to_page(r2t);
- list_del(&page->lru);
- __free_pages(page, CRST_ALLOC_ORDER);
+ ptdesc = page_ptdesc(phys_to_page(r2t));
+ list_del(&ptdesc->pt_list);
+ pagetable_free(ptdesc);
}

/**
@@ -1604,7 +1602,7 @@ static void __gmap_unshadow_r1t(struct gmap *sg, unsigned long raddr,
unsigned long *r1t)
{
unsigned long asce;
- struct page *page;
+ struct ptdesc *ptdesc;
phys_addr_t r2t;
int i;

@@ -1619,9 +1617,9 @@ static void __gmap_unshadow_r1t(struct gmap *sg, unsigned long raddr,
gmap_idte_one(asce, raddr);
r1t[i] = _REGION1_ENTRY_EMPTY;
/* Free region 2 table */
- page = phys_to_page(r2t);
- list_del(&page->lru);
- __free_pages(page, CRST_ALLOC_ORDER);
+ ptdesc = page_ptdesc(phys_to_page(r2t));
+ list_del(&ptdesc->pt_list);
+ pagetable_free(ptdesc);
}
}

@@ -1819,18 +1817,18 @@ int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
unsigned long raddr, origin, offset, len;
unsigned long *table;
phys_addr_t s_r2t;
- struct page *page;
+ struct ptdesc *ptdesc;
int rc;

BUG_ON(!gmap_is_shadow(sg));
/* Allocate a shadow region second table */
- page = gmap_alloc_crst();
- if (!page)
+ ptdesc = gmap_alloc_crst();
+ if (!ptdesc)
return -ENOMEM;
- page->index = r2t & _REGION_ENTRY_ORIGIN;
+ ptdesc->pt_index = r2t & _REGION_ENTRY_ORIGIN;
if (fake)
- page->index |= GMAP_SHADOW_FAKE_TABLE;
- s_r2t = page_to_phys(page);
+ ptdesc->pt_index |= GMAP_SHADOW_FAKE_TABLE;
+ s_r2t = page_to_phys(ptdesc_page(ptdesc));
/* Install shadow region second table */
spin_lock(&sg->guest_table_lock);
table = gmap_table_walk(sg, saddr, 4); /* get region-1 pointer */
@@ -1851,7 +1849,7 @@ int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
_REGION_ENTRY_TYPE_R1 | _REGION_ENTRY_INVALID;
if (sg->edat_level >= 1)
*table |= (r2t & _REGION_ENTRY_PROTECT);
- list_add(&page->lru, &sg->crst_list);
+ list_add(&ptdesc->pt_list, &sg->crst_list);
if (fake) {
/* nothing to protect for fake tables */
*table &= ~_REGION_ENTRY_INVALID;
@@ -1879,7 +1877,7 @@ int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
return rc;
out_free:
spin_unlock(&sg->guest_table_lock);
- __free_pages(page, CRST_ALLOC_ORDER);
+ pagetable_free(ptdesc);
return rc;
}
EXPORT_SYMBOL_GPL(gmap_shadow_r2t);
@@ -1903,18 +1901,18 @@ int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
unsigned long raddr, origin, offset, len;
unsigned long *table;
phys_addr_t s_r3t;
- struct page *page;
+ struct ptdesc *ptdesc;
int rc;

BUG_ON(!gmap_is_shadow(sg));
/* Allocate a shadow region second table */
- page = gmap_alloc_crst();
- if (!page)
+ ptdesc = gmap_alloc_crst();
+ if (!ptdesc)
return -ENOMEM;
- page->index = r3t & _REGION_ENTRY_ORIGIN;
+ ptdesc->pt_index = r3t & _REGION_ENTRY_ORIGIN;
if (fake)
- page->index |= GMAP_SHADOW_FAKE_TABLE;
- s_r3t = page_to_phys(page);
+ ptdesc->pt_index |= GMAP_SHADOW_FAKE_TABLE;
+ s_r3t = page_to_phys(ptdesc_page(ptdesc));
/* Install shadow region second table */
spin_lock(&sg->guest_table_lock);
table = gmap_table_walk(sg, saddr, 3); /* get region-2 pointer */
@@ -1935,7 +1933,7 @@ int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
_REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_INVALID;
if (sg->edat_level >= 1)
*table |= (r3t & _REGION_ENTRY_PROTECT);
- list_add(&page->lru, &sg->crst_list);
+ list_add(&ptdesc->pt_list, &sg->crst_list);
if (fake) {
/* nothing to protect for fake tables */
*table &= ~_REGION_ENTRY_INVALID;
@@ -1963,7 +1961,7 @@ int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
return rc;
out_free:
spin_unlock(&sg->guest_table_lock);
- __free_pages(page, CRST_ALLOC_ORDER);
+ pagetable_free(ptdesc);
return rc;
}
EXPORT_SYMBOL_GPL(gmap_shadow_r3t);
@@ -1987,18 +1985,18 @@ int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
unsigned long raddr, origin, offset, len;
unsigned long *table;
phys_addr_t s_sgt;
- struct page *page;
+ struct ptdesc *ptdesc;
int rc;

BUG_ON(!gmap_is_shadow(sg) || (sgt & _REGION3_ENTRY_LARGE));
/* Allocate a shadow segment table */
- page = gmap_alloc_crst();
- if (!page)
+ ptdesc = gmap_alloc_crst();
+ if (!ptdesc)
return -ENOMEM;
- page->index = sgt & _REGION_ENTRY_ORIGIN;
+ ptdesc->pt_index = sgt & _REGION_ENTRY_ORIGIN;
if (fake)
- page->index |= GMAP_SHADOW_FAKE_TABLE;
- s_sgt = page_to_phys(page);
+ ptdesc->pt_index |= GMAP_SHADOW_FAKE_TABLE;
+ s_sgt = page_to_phys(ptdesc_page(ptdesc));
/* Install shadow region second table */
spin_lock(&sg->guest_table_lock);
table = gmap_table_walk(sg, saddr, 2); /* get region-3 pointer */
@@ -2019,7 +2017,7 @@ int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
_REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INVALID;
if (sg->edat_level >= 1)
*table |= sgt & _REGION_ENTRY_PROTECT;
- list_add(&page->lru, &sg->crst_list);
+ list_add(&ptdesc->pt_list, &sg->crst_list);
if (fake) {
/* nothing to protect for fake tables */
*table &= ~_REGION_ENTRY_INVALID;
@@ -2047,7 +2045,7 @@ int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
return rc;
out_free:
spin_unlock(&sg->guest_table_lock);
- __free_pages(page, CRST_ALLOC_ORDER);
+ pagetable_free(ptdesc);
return rc;
}
EXPORT_SYMBOL_GPL(gmap_shadow_sgt);
@@ -2070,7 +2068,7 @@ int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,
int *fake)
{
unsigned long *table;
- struct page *page;
+ struct ptdesc *ptdesc;
int rc;

BUG_ON(!gmap_is_shadow(sg));
@@ -2078,10 +2076,10 @@ int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,
table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
if (table && !(*table & _SEGMENT_ENTRY_INVALID)) {
/* Shadow page tables are full pages (pte+pgste) */
- page = pfn_to_page(*table >> PAGE_SHIFT);
- *pgt = page->index & ~GMAP_SHADOW_FAKE_TABLE;
+ ptdesc = page_ptdesc(pfn_to_page(*table >> PAGE_SHIFT));
+ *pgt = ptdesc->pt_index & ~GMAP_SHADOW_FAKE_TABLE;
*dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
- *fake = !!(page->index & GMAP_SHADOW_FAKE_TABLE);
+ *fake = !!(ptdesc->pt_index & GMAP_SHADOW_FAKE_TABLE);
rc = 0;
} else {
rc = -EAGAIN;
@@ -2961,11 +2959,10 @@ EXPORT_SYMBOL_GPL(__s390_uv_destroy_range);
*/
void s390_unlist_old_asce(struct gmap *gmap)
{
- struct page *old;
+ struct ptdesc *old;

- old = virt_to_page(gmap->table);
+ old = virt_to_ptdesc(gmap->table);
spin_lock(&gmap->guest_table_lock);
- list_del(&old->lru);
/*
* Sometimes the topmost page might need to be "removed" multiple
* times, for example if the VM is rebooted into secure mode several
@@ -2980,7 +2977,7 @@ void s390_unlist_old_asce(struct gmap *gmap)
* pointers, so list_del can work (and do nothing) without
* dereferencing stale or invalid pointers.
*/
- INIT_LIST_HEAD(&old->lru);
+ list_del_init(&old->pt_list);
spin_unlock(&gmap->guest_table_lock);
}
EXPORT_SYMBOL_GPL(s390_unlist_old_asce);
@@ -3001,7 +2998,7 @@ EXPORT_SYMBOL_GPL(s390_unlist_old_asce);
int s390_replace_asce(struct gmap *gmap)
{
unsigned long asce;
- struct page *page;
+ struct ptdesc *ptdesc;
void *table;

s390_unlist_old_asce(gmap);
@@ -3010,11 +3007,11 @@ int s390_replace_asce(struct gmap *gmap)
if ((gmap->asce & _ASCE_TYPE_MASK) == _ASCE_TYPE_SEGMENT)
return -EINVAL;

- page = gmap_alloc_crst();
- if (!page)
+ ptdesc = gmap_alloc_crst();
+ if (!ptdesc)
return -ENOMEM;
- page->index = 0;
- table = page_to_virt(page);
+ ptdesc->pt_index = 0;
+ table = ptdesc_to_virt(ptdesc);
memcpy(table, gmap->table, 1UL << (CRST_ALLOC_ORDER + PAGE_SHIFT));

/*
@@ -3023,7 +3020,7 @@ int s390_replace_asce(struct gmap *gmap)
* it will be freed when the VM is torn down.
*/
spin_lock(&gmap->guest_table_lock);
- list_add(&page->lru, &gmap->crst_list);
+ list_add(&ptdesc->pt_list, &gmap->crst_list);
spin_unlock(&gmap->guest_table_lock);

/* Set new table origin while preserving existing ASCE control bits */
--
2.45.2