Re: [PATCH RFC v2 08/12] vfio/ccw: get io region info

Dong Jia Shi
2017-01-18T05:51:16Z

* Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> [2017-01-18 13:22:56 +0800]:

> * Alex Williamson <alex.williamson@redhat.com> [2017-01-17 15:49:34 -0700]:
>
> > On Thu, 12 Jan 2017 08:25:09 +0100
> > Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> wrote:
> >
> > > vfio-ccw provides an MMIO region for I/O operations. We fetch its
> > > information via ioctls here, then we can use it performing I/O
> > > instructions and retrieving I/O results later on.
> > >
> > > Signed-off-by: Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
> > > ---
> > > hw/vfio/ccw.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> > > 1 file changed, 52 insertions(+)
> > >
> > > diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
> > > index 881010b..93394c2 100644
> > > --- a/hw/vfio/ccw.c
> > > +++ b/hw/vfio/ccw.c
> > > @@ -21,11 +21,15 @@
> > > #include "hw/vfio/vfio-common.h"
> > > #include "hw/s390x/s390-ccw.h"
> > > #include "hw/s390x/ccw-device.h"
> > > +#include "standard-headers/asm-s390/vfio_ccw.h"
> > >
> > > #define TYPE_VFIO_CCW "vfio-ccw"
> > > typedef struct VFIOCCWDevice {
> > > S390CCWDevice cdev;
> > > VFIODevice vdev;
> > > + uint64_t io_region_size;
> > > + uint64_t io_region_offset;
> > > + struct ccw_io_region *io_region;
> > > } VFIOCCWDevice;
> > >
> > > static void vfio_ccw_compute_needs_reset(VFIODevice *vdev)
> > > @@ -50,6 +54,46 @@ static void vfio_ccw_reset(DeviceState *dev)
> > > ioctl(vcdev->vdev.fd, VFIO_DEVICE_RESET);
> > > }
> > >
> > > +static void vfio_ccw_get_region(VFIOCCWDevice *vcdev, Error **errp)
> > > +{
> > > + VFIODevice *vdev = &vcdev->vdev;
> > > + struct vfio_region_info *info;
> > > + int ret;
> > > +
> > > + /* Sanity check device */
> > > + if (!(vdev->flags & VFIO_DEVICE_FLAGS_CCW)) {
> > > + error_setg(errp, "vfio: Um, this isn't a vfio-ccw device");
> > > + return;
> > > + }
> > > +
> > > + if (vdev->num_regions != VFIO_CCW_NUM_REGIONS) {
> > > + error_setg(errp, "vfio: Unexpected number of the I/O region %u",
> > > + vdev->num_regions);
> > > + return;
> > > + }
> >
> > I think you want < here, not !=, otherwise you we can never add another
> > region to describe something new on a vfio-ccw device without breaking
> > this code. You've defined in the uapi that region index zero is always
> > VFIO_CCW_CONFIG_REGION_INDEX and this code only depends on that, no
> > matter what additional regions might be added. That's done below.
> >
> Right! Thanks for pointing out. I will fix.
>
Let me make it clear. I will change it to:
if (vdev->num_regions < VFIO_CCW_CONFIG_REGION_INDEX + 1) {
... ...
}

> > > +
> > > + ret = vfio_get_region_info(vdev, VFIO_CCW_CONFIG_REGION_INDEX, &info);
> > > + if (ret) {
> > > + error_setg(errp, "vfio: Error getting config info: %d", ret);
> > > + return;
> > > + }
> > > +
> > > + vcdev->io_region_size = info->size;
> > > + if (sizeof(*vcdev->io_region) != vcdev->io_region_size) {
> > > + error_setg(errp, "vfio: Unexpected size of the I/O region");
> > > + return;
> > > + }
> > > + vcdev->io_region_offset = info->offset;
> > > + vcdev->io_region = g_malloc0(info->size);
> > > +
> > > + g_free(info);
> > > +}
> > > +
> > > +static void vfio_ccw_put_region(VFIOCCWDevice *vcdev)
> > > +{
> > > + g_free(vcdev->io_region);
> > > +}
> > > +
> > > static void vfio_put_device(VFIOCCWDevice *vcdev)
> > > {
> > > g_free(vcdev->vdev.name);
> > > @@ -144,8 +188,15 @@ static void vfio_ccw_realize(DeviceState *dev, Error **errp)
> > > goto out_device_err;
> > > }
> > >
> > > + vfio_ccw_get_region(vcdev, errp);
> > > + if (*errp) {
> > > + goto out_region_err;
> > > + }
> > > +
> > > return;
> > >
> > > +out_region_err:
> > > + vfio_put_device(vcdev);
> > > out_device_err:
> > > vfio_ccw_put_group(group, path);
> > > out_group_err:
> > > @@ -166,6 +217,7 @@ static void vfio_ccw_unrealize(DeviceState *dev, Error **errp)
> > > cdc->unrealize(cdev, errp);
> > > }
> > >
> > > + vfio_ccw_put_region(vcdev);
> > > vfio_put_device(vcdev);
> > > vfio_put_group(group);
> > > }
> >
>
> --
> Dong Jia

--
Dong Jia