[RFC/PATCH 02/22] s390/mm: Abstract gmap notify bit setting

Janosch Frank
2017-11-06T22:38:52Z

Currently we use the software PGSTE bits PGSTE_IN_BIT and PGSTE_VSIE_BIT
to notify before an invalidation occurs on a prefix page or a VSIE page
respectively. Both bits only work for a PGSTE, which only exists for
page tables.

For huge page support we also need such bits for segments (pmds) so
let's introduce abstract GMAP_ENTRY_* bits that will be realized into
the respective bits when gmap DAT table entries are protected.

Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
arch/s390/include/asm/gmap.h | 4 ++++
arch/s390/mm/gmap.c | 13 ++++++++-----
2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/s390/include/asm/gmap.h b/arch/s390/include/asm/gmap.h
index 741ddba..f3d84a8 100644
--- a/arch/s390/include/asm/gmap.h
+++ b/arch/s390/include/asm/gmap.h
@@ -8,6 +8,10 @@
#ifndef _ASM_S390_GMAP_H
#define _ASM_S390_GMAP_H

+/* Generic bits for GMAP notification on DAT table entry changes. */
+#define GMAP_ENTRY_VSIE 0x2
+#define GMAP_ENTRY_IN 0x1
+
/**
* struct gmap_struct - guest address space
* @list: list head for the mm->context gmap list
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index 9757242..74e2062 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -927,7 +927,7 @@ static inline void gmap_pmd_op_end(struct gmap *gmap, pmd_t *pmdp)
* @gaddr: virtual address in the guest address space
* @pmdp: pointer to the pmd associated with the pte
* @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
- * @bits: pgste notification bits to set
+ * @bits: notification bits to set
*
* Returns 0 if successfully protected, -ENOMEM if out of memory and
* -EAGAIN if a fixup is needed.
@@ -941,6 +941,7 @@ static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr,
int rc;
pte_t *ptep;
spinlock_t *ptl = NULL;
+ unsigned long pbits = 0;

/* We have no upper segment, let's go back and fix this up. */
if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)
@@ -954,8 +955,10 @@ static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr,
return -ENOMEM;
}

+ pbits |= (bits & GMAP_ENTRY_IN) ? PGSTE_IN_BIT : 0;
+ pbits |= (bits & GMAP_ENTRY_VSIE) ? PGSTE_VSIE_BIT : 0;
/* Protect and unlock. */
- rc = ptep_force_prot(gmap->mm, gaddr, ptep, prot, bits);
+ rc = ptep_force_prot(gmap->mm, gaddr, ptep, prot, pbits);
if (ptl)
gmap_pte_op_end(ptl);
return rc;
@@ -1031,7 +1034,7 @@ int gmap_mprotect_notify(struct gmap *gmap, unsigned long gaddr,
if (!MACHINE_HAS_ESOP && prot == PROT_READ)
return -EINVAL;
down_read(&gmap->mm->mmap_sem);
- rc = gmap_protect_range(gmap, gaddr, len, prot, PGSTE_IN_BIT);
+ rc = gmap_protect_range(gmap, gaddr, len, prot, GMAP_ENTRY_IN);
up_read(&gmap->mm->mmap_sem);
return rc;
}
@@ -1153,7 +1156,7 @@ static int gmap_protect_rmap(struct gmap *sg, unsigned long raddr,
if (ptep) {
spin_lock(&sg->guest_table_lock);
rc = ptep_force_prot(parent->mm, paddr, ptep, prot,
- PGSTE_VSIE_BIT);
+ GMAP_ENTRY_VSIE);
if (!rc)
gmap_insert_rmap(sg, vmaddr, rmap);
spin_unlock(&sg->guest_table_lock);
@@ -1622,7 +1625,7 @@ struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce,
down_read(&parent->mm->mmap_sem);
rc = gmap_protect_range(parent, asce & _ASCE_ORIGIN,
((asce & _ASCE_TABLE_LENGTH) + 1) * PAGE_SIZE,
- PROT_READ, PGSTE_VSIE_BIT);
+ PROT_READ, GMAP_ENTRY_VSIE);
up_read(&parent->mm->mmap_sem);
spin_lock(&parent->shadow_lock);
new->initialized = true;
--
2.7.4