From: Eric Farman <farman@linux.ibm.com>
To: Cornelia Huck <cohuck@redhat.com>, Farhan Ali <alifm@linux.ibm.com>
Cc: Halil Pasic <pasic@linux.ibm.com>,
linux-s390@vger.kernel.org, kvm@vger.kernel.org,
Eric Farman <farman@linux.ibm.com>
Subject: [RFC PATCH v1 3/5] vfio-ccw: Copy CCW data outside length calculation
Date: Tue, 18 Jun 2019 22:23:50 +0200 [thread overview]
Message-ID: <20190618202352.39702-4-farman@linux.ibm.com> (raw)
In-Reply-To: <20190618202352.39702-1-farman@linux.ibm.com>
It doesn't make much sense to "hide" the copy to the channel_program
struct inside a routine that calculates the length of the chain.
Let's move it to the calling routine, which will later copy from
channel_program to the memory it allocated itself.
Signed-off-by: Eric Farman <farman@linux.ibm.com>
---
drivers/s390/cio/vfio_ccw_cp.c | 19 +++++++------------
1 file changed, 7 insertions(+), 12 deletions(-)
diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
index 37d513e86530..a55f8d110920 100644
--- a/drivers/s390/cio/vfio_ccw_cp.c
+++ b/drivers/s390/cio/vfio_ccw_cp.c
@@ -381,18 +381,8 @@ static void ccwchain_cda_free(struct ccwchain *chain, int idx)
static int ccwchain_calc_length(u64 iova, struct channel_program *cp)
{
struct ccw1 *ccw = cp->guest_cp;
- int cnt;
+ int cnt = 0;
- /*
- * Copy current chain from guest to host kernel.
- * Currently the chain length is limited to CCWCHAIN_LEN_MAX (256).
- * So copying 2K is enough (safe).
- */
- cnt = copy_ccw_from_iova(cp, ccw, iova, CCWCHAIN_LEN_MAX);
- if (cnt)
- return cnt;
-
- cnt = 0;
do {
cnt++;
@@ -446,7 +436,12 @@ static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp)
struct ccwchain *chain;
int len;
- /* Copy the chain from cda to cp, and count the CCWs in it */
+ /* Copy 2K (the most we support today) of possible CCWs */
+ len = copy_ccw_from_iova(cp, cp->guest_cp, cda, CCWCHAIN_LEN_MAX);
+ if (len)
+ return len;
+
+ /* Count the CCWs in the current chain */
len = ccwchain_calc_length(cda, cp);
if (len < 0)
return len;
--
2.17.1
next prev parent reply other threads:[~2019-06-18 20:24 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-18 20:23 [RFC PATCH v1 0/5] s390: more vfio-ccw code rework Eric Farman
2019-06-18 20:23 ` [RFC PATCH v1 1/5] vfio-ccw: Move guest_cp storage into common struct Eric Farman
2019-06-19 8:14 ` Cornelia Huck
2019-06-19 20:13 ` Farhan Ali
2019-06-19 20:53 ` Eric Farman
2019-06-19 21:12 ` Farhan Ali
2019-06-18 20:23 ` [RFC PATCH v1 2/5] vfio-ccw: Skip second copy of guest cp to host Eric Farman
2019-06-19 8:17 ` Cornelia Huck
2019-06-18 20:23 ` Eric Farman [this message]
2019-06-19 8:18 ` [RFC PATCH v1 3/5] vfio-ccw: Copy CCW data outside length calculation Cornelia Huck
2019-06-18 20:23 ` [RFC PATCH v1 4/5] vfio-ccw: Factor out the ccw0-to-ccw1 transition Eric Farman
2019-06-19 8:22 ` Cornelia Huck
2019-06-18 20:23 ` [RFC PATCH v1 5/5] vfio-ccw: Remove copy_ccw_from_iova() Eric Farman
2019-06-19 8:23 ` Cornelia Huck
2019-06-19 21:13 ` Farhan Ali
2019-06-19 8:25 ` [RFC PATCH v1 0/5] s390: more vfio-ccw code rework Cornelia Huck
2019-06-19 11:11 ` Eric Farman
2019-06-19 21:15 ` Farhan Ali
2019-06-21 12:25 ` Cornelia Huck
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