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vfio-ccw: Factor out the ccw0-to-ccw1 transition

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This is a really useful function, but it's buried in the
copy_ccw_from_iova() routine so that ccwchain_calc_length()
can just work with Format-1 CCWs while doing its counting.
But it means we're translating a full 2K of "CCWs" to Format-1,
when in reality there's probably far fewer in that space.

Let's factor it out, so maybe we can do something with it later.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Message-Id: <20190618202352.39702-5-farman@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
This commit is contained in:
Eric Farman 2019-06-18 22:23:51 +02:00 committed by Cornelia Huck
parent ded563f31d
commit 7f8e89a8f2
1 changed files with 25 additions and 23 deletions
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48
drivers/s390/cio/vfio_ccw_cp.c
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@ -161,6 +161,27 @@ static inline void pfn_array_idal_create_words(
idaws[0] += pa->pa_iova & (PAGE_SIZE - 1);
}
void convert_ccw0_to_ccw1(struct ccw1 *source, unsigned long len)
{
struct ccw0 ccw0;
struct ccw1 *pccw1 = source;
int i;
for (i = 0; i < len; i++) {
ccw0 = *(struct ccw0 *)pccw1;
if ((pccw1->cmd_code & 0x0f) == CCW_CMD_TIC) {
pccw1->cmd_code = CCW_CMD_TIC;
pccw1->flags = 0;
pccw1->count = 0;
} else {
pccw1->cmd_code = ccw0.cmd_code;
pccw1->flags = ccw0.flags;
pccw1->count = ccw0.count;
}
pccw1->cda = ccw0.cda;
pccw1++;
}
}
/*
* Within the domain (@mdev), copy @n bytes from a guest physical
@ -211,32 +232,9 @@ static long copy_ccw_from_iova(struct channel_program *cp,
struct ccw1 *to, u64 iova,
unsigned long len)
{
struct ccw0 ccw0;
struct ccw1 *pccw1;
int ret;
int i;
ret = copy_from_iova(cp->mdev, to, iova, len * sizeof(struct ccw1));
if (ret)
return ret;
if (!cp->orb.cmd.fmt) {
pccw1 = to;
for (i = 0; i < len; i++) {
ccw0 = *(struct ccw0 *)pccw1;
if ((pccw1->cmd_code & 0x0f) == CCW_CMD_TIC) {
pccw1->cmd_code = CCW_CMD_TIC;
pccw1->flags = 0;
pccw1->count = 0;
} else {
pccw1->cmd_code = ccw0.cmd_code;
pccw1->flags = ccw0.flags;
pccw1->count = ccw0.count;
}
pccw1->cda = ccw0.cda;
pccw1++;
}
}
return ret;
}
@ -441,6 +439,10 @@ static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp)
if (len)
return len;
/* Convert any Format-0 CCWs to Format-1 */
if (!cp->orb.cmd.fmt)
convert_ccw0_to_ccw1(cp->guest_cp, len);
/* Count the CCWs in the current chain */
len = ccwchain_calc_length(cda, cp);
if (len < 0)