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Commit 58b7e200 authored Jul 13, 2018 by Janosch Frank

s390/mm: Add gmap pmd linking



Let's allow pmds to be linked into gmap for the upcoming s390 KVM huge
page support.

Before this patch we copied the full userspace pmd entry. This is not
correct, as it contains SW defined bits that might be interpreted
differently in the GMAP context. Now we only copy over all hardware
relevant information leaving out the software bits.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>

parent 2c46e974

arch/s390/include/asm/pgtable.h

+4 −2

Original line number	Original line	Diff line number	Diff line
	@@ -270,6 +270,8 @@ static inline int is_module_addr(void *addr)
	/* Bits in the segment table entry */		/* Bits in the segment table entry */
	#define _SEGMENT_ENTRY_BITS 0xfffffffffffffe33UL		#define _SEGMENT_ENTRY_BITS 0xfffffffffffffe33UL
	#define _SEGMENT_ENTRY_BITS_LARGE 0xfffffffffff0ff33UL		#define _SEGMENT_ENTRY_BITS_LARGE 0xfffffffffff0ff33UL
			#define _SEGMENT_ENTRY_HARDWARE_BITS 0xfffffffffffffe30UL
			#define _SEGMENT_ENTRY_HARDWARE_BITS_LARGE 0xfffffffffff00730UL
	#define _SEGMENT_ENTRY_ORIGIN_LARGE ~0xfffffUL /* large page address */		#define _SEGMENT_ENTRY_ORIGIN_LARGE ~0xfffffUL /* large page address */
	#define _SEGMENT_ENTRY_ORIGIN ~0x7ffUL/* page table origin */		#define _SEGMENT_ENTRY_ORIGIN ~0x7ffUL/* page table origin */
	#define _SEGMENT_ENTRY_PROTECT 0x200 /* segment protection bit */		#define _SEGMENT_ENTRY_PROTECT 0x200 /* segment protection bit */

arch/s390/mm/gmap.c

+9 −4

Original line number	Original line	Diff line number	Diff line
	@@ -596,10 +596,15 @@ int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr)
	if (*table == _SEGMENT_ENTRY_EMPTY) {		if (*table == _SEGMENT_ENTRY_EMPTY) {
	rc = radix_tree_insert(&gmap->host_to_guest,		rc = radix_tree_insert(&gmap->host_to_guest,
	vmaddr >> PMD_SHIFT, table);		vmaddr >> PMD_SHIFT, table);
	if (!rc)		if (!rc) {
	table = pmd_val(pmd);		if (pmd_large(*pmd)) {
			table = pmd_val(pmd) &
			_SEGMENT_ENTRY_HARDWARE_BITS_LARGE;
	} else		} else
	rc = 0;		table = pmd_val(pmd) &
			_SEGMENT_ENTRY_HARDWARE_BITS;
			}
			}
	spin_unlock(&gmap->guest_table_lock);		spin_unlock(&gmap->guest_table_lock);
	spin_unlock(ptl);		spin_unlock(ptl);
	radix_tree_preload_end();		radix_tree_preload_end();