Commit 6a6dc14a authored by Eric Farman's avatar Eric Farman Committed by Heiko Carstens
Browse files

vfio/ccw: calculate number of IDAWs regardless of format 



The idal_nr_words() routine works well for 4K IDAWs, but lost its
ability to handle the old 2K formats with the removal of 31-bit
builds in commit 5a79859a ("s390: remove 31 bit support").

Since there's nothing preventing a guest from generating this IDAW
format, let's re-introduce the math for them and use both when
calculating the number of IDAWs based on the bits specified in
the ORB.

Signed-off-by: default avatarEric Farman <farman@linux.ibm.com>
Reviewed-by: default avatarMatthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
parent 667e5dba

arch/s390/include/asm/idals.h

+12 −0
Original line number Diff line number Diff line
@@ -23,6 +23,9 @@ 
#define IDA_SIZE_LOG 12 /* 11 for 2k , 12 for 4k */

#define IDA_BLOCK_SIZE (1L<<IDA_SIZE_LOG)



#define IDA_2K_SIZE_LOG 11

#define IDA_2K_BLOCK_SIZE (1L << IDA_2K_SIZE_LOG)



/*

 * Test if an address/length pair needs an idal list.

 */
@@ -42,6 +45,15 @@ static inline unsigned int idal_nr_words(void *vaddr, unsigned int length) 
		(IDA_BLOCK_SIZE-1)) >> IDA_SIZE_LOG;

}



/*

 * Return the number of 2K IDA words needed for an address/length pair.

 */

static inline unsigned int idal_2k_nr_words(void *vaddr, unsigned int length)

{

	return ((__pa(vaddr) & (IDA_2K_BLOCK_SIZE - 1)) + length +

		(IDA_2K_BLOCK_SIZE - 1)) >> IDA_2K_SIZE_LOG;

}



/*

 * Create the list of idal words for an address/length pair.

 */

drivers/s390/cio/vfio_ccw_cp.c

+16 −0
Original line number Diff line number Diff line
@@ -502,6 +502,13 @@ static int ccwchain_fetch_tic(struct ccw1 *ccw, 
 *

 * @ccw: The Channel Command Word being translated

 * @cp: Channel Program being processed

 *

 * The ORB is examined, since it specifies what IDAWs could actually be

 * used by any CCW in the channel program, regardless of whether or not

 * the CCW actually does. An ORB that does not specify Format-2-IDAW

 * Control could still contain a CCW with an IDAL, which would be

 * Format-1 and thus only move 2K with each IDAW. Thus all CCWs within

 * the channel program must follow the same size requirements.

 */

static int ccw_count_idaws(struct ccw1 *ccw,

			   struct channel_program *cp)
@@ -533,6 +540,15 @@ static int ccw_count_idaws(struct ccw1 *ccw, 
		iova = ccw->cda;

	}



	/* Format-1 IDAWs operate on 2K each */

	if (!cp->orb.cmd.c64)

		return idal_2k_nr_words((void *)iova, bytes);



	/* Using the 2K variant of Format-2 IDAWs? */

	if (cp->orb.cmd.i2k)

		return idal_2k_nr_words((void *)iova, bytes);



	/* The 'usual' case is 4K Format-2 IDAWs */

	return idal_nr_words((void *)iova, bytes);

}