Commit bcc64b57 authored by Jason Gunthorpe's avatar Jason Gunthorpe Committed by Joerg Roedel
Browse files

iommupt: Add basic support for SW bits in the page table 



SW bits can be placed on items, including table entries, single OA's and
individual items within a contiguous OA. They are guaranteed to be ignored
by the HW. The API is very basic since the only use case so far is a
single bit.

Reviewed-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
parent 36ae67b1

drivers/iommu/generic_pt/pt_common.h

+29 −0
Original line number Diff line number Diff line
@@ -342,6 +342,35 @@ static inline struct pt_table_p *pt_table_ptr(const struct pt_state *pts) 
	return __va(pt_table_pa(pts));

}



/**

 * pt_max_sw_bit() - Return the maximum software bit usable for any level and

 *                   entry

 * @common: Page table

 *

 * The swbit can be passed as bitnr to the other sw_bit functions.

 */

static inline unsigned int pt_max_sw_bit(struct pt_common *common);



/**

 * pt_test_sw_bit_acquire() - Read a software bit in an item

 * @pts: Entry to set

 *

 * Software bits are ignored by HW and can be used for any purpose by the

 * software. This does a test bit and acquire operation.

 */

static inline bool pt_test_sw_bit_acquire(struct pt_state *pts,

					  unsigned int bitnr);



/**

 * pt_set_sw_bit_release() - Set a software bit in an item

 * @pts: Entry to set

 *

 * Software bits are ignored by HW and can be used for any purpose by the

 * software. This does a set bit and release operation.

 */

static inline void pt_set_sw_bit_release(struct pt_state *pts,

					 unsigned int bitnr);



/**

 * pt_load_entry() - Read from the location pts points at into the pts

 * @pts: Table index to load

drivers/iommu/generic_pt/pt_fmt_defaults.h

+62 −0
Original line number Diff line number Diff line
@@ -202,6 +202,68 @@ static inline void pt_clear_entries(struct pt_state *pts, 
#define pt_clear_entries pt_clear_entries

#endif



/* If not supplied then SW bits are not supported */

#ifdef pt_sw_bit

static inline bool pt_test_sw_bit_acquire(struct pt_state *pts,

					  unsigned int bitnr)

{

	/* Acquire, pairs with pt_set_sw_bit_release() */

	smp_mb();

	/* For a contiguous entry the sw bit is only stored in the first item. */

	return pts->entry & pt_sw_bit(bitnr);

}

#define pt_test_sw_bit_acquire pt_test_sw_bit_acquire



static inline void pt_set_sw_bit_release(struct pt_state *pts,

					 unsigned int bitnr)

{

#if !IS_ENABLED(CONFIG_GENERIC_ATOMIC64)

	if (PT_ITEM_WORD_SIZE == sizeof(u64)) {

		u64 *entryp = pt_cur_table(pts, u64) + pts->index;

		u64 old_entry = pts->entry;

		u64 new_entry;



		do {

			new_entry = old_entry | pt_sw_bit(bitnr);

		} while (!try_cmpxchg64_release(entryp, &old_entry, new_entry));

		pts->entry = new_entry;

		return;

	}

#endif

	if (PT_ITEM_WORD_SIZE == sizeof(u32)) {

		u32 *entryp = pt_cur_table(pts, u32) + pts->index;

		u32 old_entry = pts->entry;

		u32 new_entry;



		do {

			new_entry = old_entry | pt_sw_bit(bitnr);

		} while (!try_cmpxchg_release(entryp, &old_entry, new_entry));

		pts->entry = new_entry;

	} else

		BUILD_BUG();

}

#define pt_set_sw_bit_release pt_set_sw_bit_release

#else

static inline unsigned int pt_max_sw_bit(struct pt_common *common)

{

	return 0;

}



extern void __pt_no_sw_bit(void);

static inline bool pt_test_sw_bit_acquire(struct pt_state *pts,

					  unsigned int bitnr)

{

	__pt_no_sw_bit();

	return false;

}



static inline void pt_set_sw_bit_release(struct pt_state *pts,

					 unsigned int bitnr)

{

	__pt_no_sw_bit();

}

#endif



/*

 * Format can call in the pt_install_leaf_entry() to check the arguments are all

 * aligned correctly.