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Commit a9e00d83 authored by Janosch Frank's avatar Janosch Frank
Browse files

s390/mm: Add huge page gmap linking support 



Let's allow huge pmd linking when enabled through the
KVM_CAP_S390_HPAGE_1M capability. Also we can now restrict gmap
invalidation and notification to the cases where the capability has
been activated and save some cycles when that's not the case.

Signed-off-by: default avatarJanosch Frank <frankja@linux.ibm.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
parent 7d735b9a

arch/s390/include/asm/mmu.h

+2 −0
Original line number Diff line number Diff line
@@ -24,6 +24,8 @@ typedef struct { 
	unsigned int uses_skeys:1;

	/* The mmu context uses CMM. */

	unsigned int uses_cmm:1;

	/* The gmaps associated with this context are allowed to use huge pages. */

	unsigned int allow_gmap_hpage_1m:1;

} mm_context_t;



#define INIT_MM_CONTEXT(name)						   \

arch/s390/include/asm/mmu_context.h

+1 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ static inline int init_new_context(struct task_struct *tsk, 
	mm->context.has_pgste = 0;

	mm->context.uses_skeys = 0;

	mm->context.uses_cmm = 0;

	mm->context.allow_gmap_hpage_1m = 0;

#endif

	switch (mm->context.asce_limit) {

	case _REGION2_SIZE:

arch/s390/mm/gmap.c

+6 −3
Original line number Diff line number Diff line
@@ -2,8 +2,10 @@ 
/*

 *  KVM guest address space mapping code

 *

 *    Copyright IBM Corp. 2007, 2016

 *    Copyright IBM Corp. 2007, 2016, 2018

 *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>

 *		 David Hildenbrand <david@redhat.com>

 *		 Janosch Frank <frankja@linux.vnet.ibm.com>

 */



#include <linux/kernel.h>
@@ -588,8 +590,8 @@ int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr) 
		return -EFAULT;

	pmd = pmd_offset(pud, vmaddr);

	VM_BUG_ON(pmd_none(*pmd));

	/* large pmds cannot yet be handled */

	if (pmd_large(*pmd))

	/* Are we allowed to use huge pages? */

	if (pmd_large(*pmd) && !gmap->mm->context.allow_gmap_hpage_1m)

		return -EFAULT;

	/* Link gmap segment table entry location to page table. */

	rc = radix_tree_preload(GFP_KERNEL);
@@ -1632,6 +1634,7 @@ struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce, 
	unsigned long limit;

	int rc;



	BUG_ON(parent->mm->context.allow_gmap_hpage_1m);

	BUG_ON(gmap_is_shadow(parent));

	spin_lock(&parent->shadow_lock);

	sg = gmap_find_shadow(parent, asce, edat_level);

arch/s390/mm/pgtable.c

+4 −4
Original line number Diff line number Diff line
@@ -347,7 +347,7 @@ static inline void pmdp_idte_local(struct mm_struct *mm, 
			    mm->context.asce, IDTE_LOCAL);

	else

		__pmdp_idte(addr, pmdp, 0, 0, IDTE_LOCAL);

	if (mm_has_pgste(mm))

	if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)

		gmap_pmdp_idte_local(mm, addr);

}
@@ -357,15 +357,15 @@ static inline void pmdp_idte_global(struct mm_struct *mm, 
	if (MACHINE_HAS_TLB_GUEST) {

		__pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,

			    mm->context.asce, IDTE_GLOBAL);

		if (mm_has_pgste(mm))

		if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)

			gmap_pmdp_idte_global(mm, addr);

	} else if (MACHINE_HAS_IDTE) {

		__pmdp_idte(addr, pmdp, 0, 0, IDTE_GLOBAL);

		if (mm_has_pgste(mm))

		if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)

			gmap_pmdp_idte_global(mm, addr);

	} else {

		__pmdp_csp(pmdp);

		if (mm_has_pgste(mm))

		if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)

			gmap_pmdp_csp(mm, addr);

	}

}