* [PATCH v2 1/1] vfio: ccw: fix bad ptr math for TIC cda translation
@ 2017-07-21 1:14 Dong Jia Shi
[not found] ` <20170724071053.GA7483@bjsdjshi@linux.vnet.ibm.com>
0 siblings, 1 reply; 2+ messages in thread
From: Dong Jia Shi @ 2017-07-21 1:14 UTC (permalink / raw)
To: linux-s390, kvm; +Cc: cohuck, borntraeger, bjsdjshi, Jason J. Herne
From: "Jason J. Herne" <jjherne@linux.vnet.ibm.com>
When we are translating channel data addresses from guest to host
address space for TIC instructions we are getting incorrect
addresses because of a pointer arithmetic error.
We currently calculate the offset of the TIC's cda from the start
of the channel program chain (ccw->cda - ccw_head). We then add
that to the address of the ccw chain in host memory (iter->ch_ccw).
The problem is that iter->ch_ccw is a pointer to struct ccw1 so
when we increment it we are actually incrementing by the size of
struct ccw1 which is 8 bytes. The intent was to increment by
n-bytes, not n*8.
The fix: cast iter->ch_ccw to char* so it will be incremented by
n*1.
Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
---
drivers/s390/cio/vfio_ccw_cp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
index ba6ac83a6c25..5ccfdc80d0ec 100644
--- a/drivers/s390/cio/vfio_ccw_cp.c
+++ b/drivers/s390/cio/vfio_ccw_cp.c
@@ -481,7 +481,7 @@ static int ccwchain_fetch_tic(struct ccwchain *chain,
ccw_tail = ccw_head + (iter->ch_len - 1) * sizeof(struct ccw1);
if ((ccw_head <= ccw->cda) && (ccw->cda <= ccw_tail)) {
- ccw->cda = (__u32) (addr_t) (iter->ch_ccw +
+ ccw->cda = (__u32) (addr_t) (((char *)iter->ch_ccw) +
(ccw->cda - ccw_head));
return 0;
}
--
2.11.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2 1/1] vfio: ccw: fix bad ptr math for TIC cda translation
[not found] ` <20170724071053.GA7483@bjsdjshi@linux.vnet.ibm.com>
@ 2017-07-24 8:01 ` Cornelia Huck
0 siblings, 0 replies; 2+ messages in thread
From: Cornelia Huck @ 2017-07-24 8:01 UTC (permalink / raw)
To: Dong Jia Shi; +Cc: pasic, linux-s390, kvm, borntraeger, Jason J. Herne
On Mon, 24 Jul 2017 15:10:53 +0800
Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> wrote:
> * Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> [2017-07-21 03:14:36 +0200]:
>
> As Halil requested, add him into the loop.
>
> > From: "Jason J. Herne" <jjherne@linux.vnet.ibm.com>
> >
> > When we are translating channel data addresses from guest to host
> > address space for TIC instructions we are getting incorrect
> > addresses because of a pointer arithmetic error.
> >
> > We currently calculate the offset of the TIC's cda from the start
> > of the channel program chain (ccw->cda - ccw_head). We then add
> > that to the address of the ccw chain in host memory (iter->ch_ccw).
> > The problem is that iter->ch_ccw is a pointer to struct ccw1 so
> > when we increment it we are actually incrementing by the size of
> > struct ccw1 which is 8 bytes. The intent was to increment by
> > n-bytes, not n*8.
> >
> > The fix: cast iter->ch_ccw to char* so it will be incremented by
> > n*1.
> >
> > Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
> > Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
> > Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
> > ---
> > drivers/s390/cio/vfio_ccw_cp.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
> > index ba6ac83a6c25..5ccfdc80d0ec 100644
> > --- a/drivers/s390/cio/vfio_ccw_cp.c
> > +++ b/drivers/s390/cio/vfio_ccw_cp.c
> > @@ -481,7 +481,7 @@ static int ccwchain_fetch_tic(struct ccwchain *chain,
> > ccw_tail = ccw_head + (iter->ch_len - 1) * sizeof(struct ccw1);
> >
> > if ((ccw_head <= ccw->cda) && (ccw->cda <= ccw_tail)) {
> > - ccw->cda = (__u32) (addr_t) (iter->ch_ccw +
> > + ccw->cda = (__u32) (addr_t) (((char *)iter->ch_ccw) +
> > (ccw->cda - ccw_head));
> > return 0;
> > }
Thanks, applied.
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2017-07-21 1:14 [PATCH v2 1/1] vfio: ccw: fix bad ptr math for TIC cda translation Dong Jia Shi
[not found] ` <20170724071053.GA7483@bjsdjshi@linux.vnet.ibm.com>
2017-07-24 8:01 ` Cornelia Huck
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