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Commit 2d42f947 authored by Claudio Imbrenda's avatar Claudio Imbrenda Committed by Martin Schwidefsky
Browse files

s390/kvm: Add PGSTE manipulation functions 



Add PGSTE manipulation functions:
* set_pgste_bits sets specific bits in a PGSTE
* get_pgste returns the whole PGSTE
* pgste_perform_essa manipulates a PGSTE to set specific storage states
* ESSA_[SG]ET_* macros used to indicate the action for manipulate_pgste

Signed-off-by: default avatarClaudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Reviewed-by: default avatarJanosch Frank <frankja@de.ibm.com>
Reviewed-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent b13de4b7

arch/s390/include/asm/page-states.h

0 → 100644
+19 −0
Original line number Diff line number Diff line 
/*

 *    Copyright IBM Corp. 2017

 *    Author(s): Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>

 */



#ifndef PAGE_STATES_H

#define PAGE_STATES_H



#define ESSA_GET_STATE			0

#define ESSA_SET_STABLE			1

#define ESSA_SET_UNUSED			2

#define ESSA_SET_VOLATILE		3

#define ESSA_SET_POT_VOLATILE		4

#define ESSA_SET_STABLE_RESIDENT	5

#define ESSA_SET_STABLE_IF_RESIDENT	6



#define ESSA_MAX	ESSA_SET_STABLE_IF_RESIDENT



#endif

arch/s390/include/asm/pgtable.h

+12 −4
Original line number Diff line number Diff line
@@ -376,6 +376,8 @@ static inline int is_module_addr(void *addr) 
#define _PGSTE_GPS_USAGE_MASK		0x0000000003000000UL

#define _PGSTE_GPS_USAGE_STABLE		0x0000000000000000UL

#define _PGSTE_GPS_USAGE_UNUSED		0x0000000001000000UL

#define _PGSTE_GPS_USAGE_POT_VOLATILE	0x0000000002000000UL

#define _PGSTE_GPS_USAGE_VOLATILE	_PGSTE_GPS_USAGE_MASK



/*

 * A user page table pointer has the space-switch-event bit, the
@@ -1041,6 +1043,12 @@ int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr); 
int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,

			  unsigned char *key);



int set_pgste_bits(struct mm_struct *mm, unsigned long addr,

				unsigned long bits, unsigned long value);

int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep);

int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,

			unsigned long *oldpte, unsigned long *oldpgste);



/*

 * Certain architectures need to do special things when PTEs

 * within a page table are directly modified.  Thus, the following

arch/s390/mm/page-states.c

+1 −2
Original line number Diff line number Diff line
@@ -13,8 +13,7 @@ 
#include <linux/gfp.h>

#include <linux/init.h>



#define ESSA_SET_STABLE		1

#define ESSA_SET_UNUSED		2

#include <asm/page-states.h>



static int cmma_flag = 1;

arch/s390/mm/pgtable.c

+153 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#include <asm/tlb.h>

#include <asm/tlbflush.h>

#include <asm/mmu_context.h>

#include <asm/page-states.h>



static inline pte_t ptep_flush_direct(struct mm_struct *mm,

				      unsigned long addr, pte_t *ptep)
@@ -787,4 +788,156 @@ int get_guest_storage_key(struct mm_struct *mm, unsigned long addr, 
	return 0;

}

EXPORT_SYMBOL(get_guest_storage_key);



/**

 * pgste_perform_essa - perform ESSA actions on the PGSTE.

 * @mm: the memory context. It must have PGSTEs, no check is performed here!

 * @hva: the host virtual address of the page whose PGSTE is to be processed

 * @orc: the specific action to perform, see the ESSA_SET_* macros.

 * @oldpte: the PTE will be saved there if the pointer is not NULL.

 * @oldpgste: the old PGSTE will be saved there if the pointer is not NULL.

 *

 * Return: 1 if the page is to be added to the CBRL, otherwise 0,

 *	   or < 0 in case of error. -EINVAL is returned for invalid values

 *	   of orc, -EFAULT for invalid addresses.

 */

int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,

			unsigned long *oldpte, unsigned long *oldpgste)

{

	unsigned long pgstev;

	spinlock_t *ptl;

	pgste_t pgste;

	pte_t *ptep;

	int res = 0;



	WARN_ON_ONCE(orc > ESSA_MAX);

	if (unlikely(orc > ESSA_MAX))

		return -EINVAL;

	ptep = get_locked_pte(mm, hva, &ptl);

	if (unlikely(!ptep))

		return -EFAULT;

	pgste = pgste_get_lock(ptep);

	pgstev = pgste_val(pgste);

	if (oldpte)

		*oldpte = pte_val(*ptep);

	if (oldpgste)

		*oldpgste = pgstev;



	switch (orc) {

	case ESSA_GET_STATE:

		break;

	case ESSA_SET_STABLE:

		pgstev &= ~_PGSTE_GPS_USAGE_MASK;

		pgstev |= _PGSTE_GPS_USAGE_STABLE;

		break;

	case ESSA_SET_UNUSED:

		pgstev &= ~_PGSTE_GPS_USAGE_MASK;

		pgstev |= _PGSTE_GPS_USAGE_UNUSED;

		if (pte_val(*ptep) & _PAGE_INVALID)

			res = 1;

		break;

	case ESSA_SET_VOLATILE:

		pgstev &= ~_PGSTE_GPS_USAGE_MASK;

		pgstev |= _PGSTE_GPS_USAGE_VOLATILE;

		if (pte_val(*ptep) & _PAGE_INVALID)

			res = 1;

		break;

	case ESSA_SET_POT_VOLATILE:

		pgstev &= ~_PGSTE_GPS_USAGE_MASK;

		if (!(pte_val(*ptep) & _PAGE_INVALID)) {

			pgstev |= _PGSTE_GPS_USAGE_POT_VOLATILE;

			break;

		}

		if (pgstev & _PGSTE_GPS_ZERO) {

			pgstev |= _PGSTE_GPS_USAGE_VOLATILE;

			break;

		}

		if (!(pgstev & PGSTE_GC_BIT)) {

			pgstev |= _PGSTE_GPS_USAGE_VOLATILE;

			res = 1;

			break;

		}

		break;

	case ESSA_SET_STABLE_RESIDENT:

		pgstev &= ~_PGSTE_GPS_USAGE_MASK;

		pgstev |= _PGSTE_GPS_USAGE_STABLE;

		/*

		 * Since the resident state can go away any time after this

		 * call, we will not make this page resident. We can revisit

		 * this decision if a guest will ever start using this.

		 */

		break;

	case ESSA_SET_STABLE_IF_RESIDENT:

		if (!(pte_val(*ptep) & _PAGE_INVALID)) {

			pgstev &= ~_PGSTE_GPS_USAGE_MASK;

			pgstev |= _PGSTE_GPS_USAGE_STABLE;

		}

		break;

	default:

		/* we should never get here! */

		break;

	}

	/* If we are discarding a page, set it to logical zero */

	if (res)

		pgstev |= _PGSTE_GPS_ZERO;



	pgste_val(pgste) = pgstev;

	pgste_set_unlock(ptep, pgste);

	pte_unmap_unlock(ptep, ptl);

	return res;

}

EXPORT_SYMBOL(pgste_perform_essa);



/**

 * set_pgste_bits - set specific PGSTE bits.

 * @mm: the memory context. It must have PGSTEs, no check is performed here!

 * @hva: the host virtual address of the page whose PGSTE is to be processed

 * @bits: a bitmask representing the bits that will be touched

 * @value: the values of the bits to be written. Only the bits in the mask

 *	   will be written.

 *

 * Return: 0 on success, < 0 in case of error.

 */

int set_pgste_bits(struct mm_struct *mm, unsigned long hva,

			unsigned long bits, unsigned long value)

{

	spinlock_t *ptl;

	pgste_t new;

	pte_t *ptep;



	ptep = get_locked_pte(mm, hva, &ptl);

	if (unlikely(!ptep))

		return -EFAULT;

	new = pgste_get_lock(ptep);



	pgste_val(new) &= ~bits;

	pgste_val(new) |= value & bits;



	pgste_set_unlock(ptep, new);

	pte_unmap_unlock(ptep, ptl);

	return 0;

}

EXPORT_SYMBOL(set_pgste_bits);



/**

 * get_pgste - get the current PGSTE for the given address.

 * @mm: the memory context. It must have PGSTEs, no check is performed here!

 * @hva: the host virtual address of the page whose PGSTE is to be processed

 * @pgstep: will be written with the current PGSTE for the given address.

 *

 * Return: 0 on success, < 0 in case of error.

 */

int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep)

{

	spinlock_t *ptl;

	pte_t *ptep;



	ptep = get_locked_pte(mm, hva, &ptl);

	if (unlikely(!ptep))

		return -EFAULT;

	*pgstep = pgste_val(pgste_get(ptep));

	pte_unmap_unlock(ptep, ptl);

	return 0;

}

EXPORT_SYMBOL(get_pgste);

#endif