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Commit 5b6c963b authored by David Hildenbrand's avatar David Hildenbrand Committed by Christian Borntraeger
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s390/mm: allow to check if a gmap shadow is valid 



It will be very helpful to have a mechanism to check without any locks
if a given gmap shadow is still valid and matches the given properties.

Acked-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 4a494439

arch/s390/include/asm/gmap.h

+1 −0
Original line number Diff line number Diff line
@@ -109,6 +109,7 @@ int gmap_read_table(struct gmap *gmap, unsigned long gaddr, unsigned long *val); 


struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce,

			 int edat_level);

int gmap_shadow_valid(struct gmap *sg, unsigned long asce, int edat_level);

int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,

		    int fake);

int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,

arch/s390/mm/gmap.c

+20 −0
Original line number Diff line number Diff line
@@ -1407,6 +1407,26 @@ static struct gmap *gmap_find_shadow(struct gmap *parent, unsigned long asce, 
	return NULL;

}



/**

 * gmap_shadow_valid - check if a shadow guest address space matches the

 *                     given properties and is still valid

 * @sg: pointer to the shadow guest address space structure

 * @asce: ASCE for which the shadow table is requested

 * @edat_level: edat level to be used for the shadow translation

 *

 * Returns 1 if the gmap shadow is still valid and matches the given

 * properties, the caller can continue using it. Returns 0 otherwise, the

 * caller has to request a new shadow gmap in this case.

 *

 */

int gmap_shadow_valid(struct gmap *sg, unsigned long asce, int edat_level)

{

	if (sg->removed)

		return 0;

	return sg->orig_asce == asce && sg->edat_level == edat_level;

}

EXPORT_SYMBOL_GPL(gmap_shadow_valid);



/**

 * gmap_shadow - create/find a shadow guest address space

 * @parent: pointer to the parent gmap