Commit 1d897e47 authored by Eric Farman's avatar Eric Farman Committed by Cornelia Huck
Browse files

vfio-ccw: Move guest_cp storage into common struct 



Rather than allocating/freeing a piece of memory every time
we try to figure out how long a CCW chain is, let's use a piece
of memory allocated for each device.

The io_mutex added with commit 4f766173 ("vfio-ccw: protect
the I/O region") is held for the duration of the VFIO_CCW_EVENT_IO_REQ
event that accesses/uses this space, so there should be no race
concerns with another CPU attempting an (unexpected) SSCH for the
same device.

Suggested-by: default avatarCornelia Huck <cohuck@redhat.com>
Signed-off-by: default avatarEric Farman <farman@linux.ibm.com>
Message-Id: <20190618202352.39702-2-farman@linux.ibm.com>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Reviewed-by: default avatarFarhan Ali <alifm@linux.ibm.com>
Signed-off-by: default avatarCornelia Huck <cohuck@redhat.com>
parent 01aa26c6

drivers/s390/cio/vfio_ccw_cp.c

+4 −19
Original line number Diff line number Diff line
@@ -16,12 +16,6 @@ 


#include "vfio_ccw_cp.h"



/*

 * Max length for ccw chain.

 * XXX: Limit to 256, need to check more?

 */

#define CCWCHAIN_LEN_MAX	256



struct pfn_array {

	/* Starting guest physical I/O address. */

	unsigned long		pa_iova;
@@ -386,7 +380,7 @@ static void ccwchain_cda_free(struct ccwchain *chain, int idx) 
 */

static int ccwchain_calc_length(u64 iova, struct channel_program *cp)

{

	struct ccw1 *ccw, *p;

	struct ccw1 *ccw = cp->guest_cp;

	int cnt;



	/*
@@ -394,15 +388,9 @@ static int ccwchain_calc_length(u64 iova, struct channel_program *cp) 
	 * Currently the chain length is limited to CCWCHAIN_LEN_MAX (256).

	 * So copying 2K is enough (safe).

	 */

	p = ccw = kcalloc(CCWCHAIN_LEN_MAX, sizeof(*ccw), GFP_KERNEL);

	if (!ccw)

		return -ENOMEM;



	cnt = copy_ccw_from_iova(cp, ccw, iova, CCWCHAIN_LEN_MAX);

	if (cnt) {

		kfree(ccw);

	if (cnt)

		return cnt;

	}



	cnt = 0;

	do {
@@ -413,10 +401,8 @@ static int ccwchain_calc_length(u64 iova, struct channel_program *cp) 
		 * orb specified one of the unsupported formats, we defer

		 * checking for IDAWs in unsupported formats to here.

		 */

		if ((!cp->orb.cmd.c64 || cp->orb.cmd.i2k) && ccw_is_idal(ccw)) {

			kfree(p);

		if ((!cp->orb.cmd.c64 || cp->orb.cmd.i2k) && ccw_is_idal(ccw))

			return -EOPNOTSUPP;

		}



		/*

		 * We want to keep counting if the current CCW has the
@@ -435,7 +421,6 @@ static int ccwchain_calc_length(u64 iova, struct channel_program *cp) 
	if (cnt == CCWCHAIN_LEN_MAX + 1)

		cnt = -EINVAL;



	kfree(p);

	return cnt;

}
@@ -461,7 +446,7 @@ static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp) 
	struct ccwchain *chain;

	int len, ret;



	/* Get chain length. */

	/* Copy the chain from cda to cp, and count the CCWs in it */

	len = ccwchain_calc_length(cda, cp);

	if (len < 0)

		return len;

drivers/s390/cio/vfio_ccw_cp.h

+7 −0
Original line number Diff line number Diff line
@@ -16,6 +16,12 @@ 


#include "orb.h"



/*

 * Max length for ccw chain.

 * XXX: Limit to 256, need to check more?

 */

#define CCWCHAIN_LEN_MAX	256



/**

 * struct channel_program - manage information for channel program

 * @ccwchain_list: list head of ccwchains
@@ -32,6 +38,7 @@ struct channel_program { 
	union orb orb;

	struct device *mdev;

	bool initialized;

	struct ccw1 *guest_cp;

};



extern int cp_init(struct channel_program *cp, struct device *mdev,

drivers/s390/cio/vfio_ccw_drv.c

+7 −0
Original line number Diff line number Diff line
@@ -129,6 +129,11 @@ static int vfio_ccw_sch_probe(struct subchannel *sch) 
	if (!private)

		return -ENOMEM;



	private->cp.guest_cp = kcalloc(CCWCHAIN_LEN_MAX, sizeof(struct ccw1),

				       GFP_KERNEL);

	if (!private->cp.guest_cp)

		goto out_free;



	private->io_region = kmem_cache_zalloc(vfio_ccw_io_region,

					       GFP_KERNEL | GFP_DMA);

	if (!private->io_region)
@@ -169,6 +174,7 @@ out_free: 
		kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);

	if (private->io_region)

		kmem_cache_free(vfio_ccw_io_region, private->io_region);

	kfree(private->cp.guest_cp);

	kfree(private);

	return ret;

}
@@ -185,6 +191,7 @@ static int vfio_ccw_sch_remove(struct subchannel *sch) 


	kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);

	kmem_cache_free(vfio_ccw_io_region, private->io_region);

	kfree(private->cp.guest_cp);

	kfree(private);



	return 0;

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