| Message ID | 20181122165457.4517-3-cohuck@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vfio-ccw: support hsch/csch (QEMU part) | expand |
On 22/11/2018 17:54, Cornelia Huck wrote: > A vfio-ccw device may provide an async command subregion for > issuing halt/clear subchannel requests. If it is present, use > it for sending halt/clear request to the device; if not, fall > back to emulation (as done today). > > Signed-off-by: Cornelia Huck <cohuck@redhat.com> > --- > hw/s390x/css.c | 27 +++++++-- > hw/vfio/ccw.c | 109 +++++++++++++++++++++++++++++++++++- > include/hw/s390x/s390-ccw.h | 3 + > 3 files changed, 133 insertions(+), 6 deletions(-) > > diff --git a/hw/s390x/css.c b/hw/s390x/css.c > index 04ec5cc970..0897c041c5 100644 > --- a/hw/s390x/css.c > +++ b/hw/s390x/css.c > @@ -22,6 +22,7 @@ > #include "trace.h" > #include "hw/s390x/s390_flic.h" > #include "hw/s390x/s390-virtio-ccw.h" > +#include "hw/s390x/s390-ccw.h" > > typedef struct CrwContainer { > CRW crw; > @@ -1194,6 +1195,26 @@ static void sch_handle_start_func_virtual(SubchDev *sch) > > } > > +static void sch_handle_halt_func_passthrough(SubchDev *sch) > +{ > + int ret; > + > + ret = vfio_ccw_handle_halt(sch); > + if (ret == -ENOSYS) { > + sch_handle_halt_func(sch); > + } > +} > + > +static void sch_handle_clear_func_passthrough(SubchDev *sch) > +{ > + int ret; > + > + ret = vfio_ccw_handle_clear(sch); > + if (ret == -ENOSYS) { > + sch_handle_clear_func(sch); > + } > +} > + > static IOInstEnding sch_handle_start_func_passthrough(SubchDev *sch) > { > > @@ -1237,11 +1258,9 @@ IOInstEnding do_subchannel_work_passthrough(SubchDev *sch) > SCSW *s = &sch->curr_status.scsw; > > if (s->ctrl & SCSW_FCTL_CLEAR_FUNC) { > - /* TODO: Clear handling */ > - sch_handle_clear_func(sch); > + sch_handle_clear_func_passthrough(sch); > } else if (s->ctrl & SCSW_FCTL_HALT_FUNC) { > - /* TODO: Halt handling */ > - sch_handle_halt_func(sch); > + sch_handle_halt_func_passthrough(sch); > } else if (s->ctrl & SCSW_FCTL_START_FUNC) { > return sch_handle_start_func_passthrough(sch); > } > diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c > index 9246729a75..dd0fecf168 100644 > --- a/hw/vfio/ccw.c > +++ b/hw/vfio/ccw.c > @@ -2,9 +2,12 @@ > * vfio based subchannel assignment support > * > * Copyright 2017 IBM Corp. > + * Copyright 2018 Red Hat, Inc. > + * > * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> > * Xiao Feng Ren <renxiaof@linux.vnet.ibm.com> > * Pierre Morel <pmorel@linux.vnet.ibm.com> > + * Cornelia Huck <cohuck@redhat.com> > * > * This work is licensed under the terms of the GNU GPL, version 2 or (at > * your option) any later version. See the COPYING file in the top-level > @@ -32,6 +35,9 @@ typedef struct VFIOCCWDevice { > uint64_t io_region_size; > uint64_t io_region_offset; > struct ccw_io_region *io_region; > + uint64_t async_cmd_region_size; > + uint64_t async_cmd_region_offset; > + struct ccw_cmd_region *async_cmd_region; > EventNotifier io_notifier; > bool force_orb_pfch; > bool warned_orb_pfch; > @@ -114,6 +120,87 @@ again: > } > } > > +int vfio_ccw_handle_clear(SubchDev *sch) > +{ > + S390CCWDevice *cdev = sch->driver_data; > + VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev); > + struct ccw_cmd_region *region = vcdev->async_cmd_region; > + int ret; > + > + if (!vcdev->async_cmd_region) { > + /* Async command region not available, fall back to emulation */ > + return -ENOSYS; > + } > + > + memset(region, 0, sizeof(*region)); > + region->command = VFIO_CCW_ASYNC_CMD_CSCH; > + > +again: > + ret = pwrite(vcdev->vdev.fd, region, > + vcdev->async_cmd_region_size, vcdev->async_cmd_region_offset); > + if (ret != vcdev->async_cmd_region_size) { > + if (errno == EAGAIN) { Where do the EAGAIN come from? > + goto again; > + } > + error_report("vfio-ccw: wirte I/O region failed with errno=%d", errno); > + ret = -errno; > + } else { > + ret = region->ret_code; > + } > + switch (ret) { > + case 0: > + case -ENODEV: > + case -EACCES: should never happen? > + return 0; > + case -EFAULT: > + default: > + sch_gen_unit_exception(sch); > + css_inject_io_interrupt(sch); > + return 0; > + } > +} > + otherwise LGTM
On Fri, 23 Nov 2018 15:13:12 +0100 Pierre Morel <pmorel@linux.ibm.com> wrote: > On 22/11/2018 17:54, Cornelia Huck wrote: > > A vfio-ccw device may provide an async command subregion for > > issuing halt/clear subchannel requests. If it is present, use > > it for sending halt/clear request to the device; if not, fall > > back to emulation (as done today). > > > > Signed-off-by: Cornelia Huck <cohuck@redhat.com> > > --- > > hw/s390x/css.c | 27 +++++++-- > > hw/vfio/ccw.c | 109 +++++++++++++++++++++++++++++++++++- > > include/hw/s390x/s390-ccw.h | 3 + > > 3 files changed, 133 insertions(+), 6 deletions(-) > > > > @@ -114,6 +120,87 @@ again: > > } > > } > > > > +int vfio_ccw_handle_clear(SubchDev *sch) > > +{ > > + S390CCWDevice *cdev = sch->driver_data; > > + VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev); > > + struct ccw_cmd_region *region = vcdev->async_cmd_region; > > + int ret; > > + > > + if (!vcdev->async_cmd_region) { > > + /* Async command region not available, fall back to emulation */ > > + return -ENOSYS; > > + } > > + > > + memset(region, 0, sizeof(*region)); > > + region->command = VFIO_CCW_ASYNC_CMD_CSCH; > > + > > +again: > > + ret = pwrite(vcdev->vdev.fd, region, > > + vcdev->async_cmd_region_size, vcdev->async_cmd_region_offset); > > + if (ret != vcdev->async_cmd_region_size) { > > + if (errno == EAGAIN) { > > > Where do the EAGAIN come from? It might be set by pwrite. > > > > + goto again; > > + } > > + error_report("vfio-ccw: wirte I/O region failed with errno=%d", errno); I should also fix up this message here and for hsch as well :) > > + ret = -errno; > > + } else { > > + ret = region->ret_code; > > + } > > + switch (ret) { > > + case 0: > > + case -ENODEV: > > + case -EACCES: > > should never happen? It should not happen; but it can nevertheless be returned, so... > > > + return 0; > > + case -EFAULT: > > + default: > > + sch_gen_unit_exception(sch); > > + css_inject_io_interrupt(sch); > > + return 0; > > + } > > +} > > + > > otherwise LGTM Thanks!
On 26/11/2018 10:58, Cornelia Huck wrote: > On Fri, 23 Nov 2018 15:13:12 +0100 > Pierre Morel <pmorel@linux.ibm.com> wrote: > >> On 22/11/2018 17:54, Cornelia Huck wrote: >>> A vfio-ccw device may provide an async command subregion for >>> issuing halt/clear subchannel requests. If it is present, use >>> it for sending halt/clear request to the device; if not, fall >>> back to emulation (as done today). >>> >>> Signed-off-by: Cornelia Huck <cohuck@redhat.com> >>> --- >>> hw/s390x/css.c | 27 +++++++-- >>> hw/vfio/ccw.c | 109 +++++++++++++++++++++++++++++++++++- >>> include/hw/s390x/s390-ccw.h | 3 + >>> 3 files changed, 133 insertions(+), 6 deletions(-) >>> > >>> @@ -114,6 +120,87 @@ again: >>> } >>> } >>> >>> +int vfio_ccw_handle_clear(SubchDev *sch) >>> +{ >>> + S390CCWDevice *cdev = sch->driver_data; >>> + VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev); >>> + struct ccw_cmd_region *region = vcdev->async_cmd_region; >>> + int ret; >>> + >>> + if (!vcdev->async_cmd_region) { >>> + /* Async command region not available, fall back to emulation */ >>> + return -ENOSYS; >>> + } >>> + >>> + memset(region, 0, sizeof(*region)); >>> + region->command = VFIO_CCW_ASYNC_CMD_CSCH; >>> + >>> +again: >>> + ret = pwrite(vcdev->vdev.fd, region, >>> + vcdev->async_cmd_region_size, vcdev->async_cmd_region_offset); >>> + if (ret != vcdev->async_cmd_region_size) { >>> + if (errno == EAGAIN) { >> >> >> Where do the EAGAIN come from? > > It might be set by pwrite. I saw that the man indicate this, and so we are legitimate to handle the fail case, but I did not find EAGAIN in the path of the write for accessing devices and I did not find it in the access to the CSS. If we do not set it explicitly from the driver, the concern I have is: isn't it dangerous to try again and shouldn't we better abort? > >> >> >>> + goto again; >>> + } >>> + error_report("vfio-ccw: wirte I/O region failed with errno=%d", errno); > > I should also fix up this message here and for hsch as well :) > >>> + ret = -errno; >>> + } else { >>> + ret = region->ret_code; >>> + } >>> + switch (ret) { >>> + case 0: >>> + case -ENODEV: >>> + case -EACCES: >> >> should never happen? > > It should not happen; but it can nevertheless be returned, so... I understand: nothing to clear :) > >> >>> + return 0; >>> + case -EFAULT: >>> + default: >>> + sch_gen_unit_exception(sch); >>> + css_inject_io_interrupt(sch); >>> + return 0; >>> + } >>> +} >>> + >> >> otherwise LGTM > > Thanks! >
On Mon, 26 Nov 2018 19:01:55 +0100 Pierre Morel <pmorel@linux.ibm.com> wrote: > On 26/11/2018 10:58, Cornelia Huck wrote: > > On Fri, 23 Nov 2018 15:13:12 +0100 > > Pierre Morel <pmorel@linux.ibm.com> wrote: > > > >> On 22/11/2018 17:54, Cornelia Huck wrote: > >>> A vfio-ccw device may provide an async command subregion for > >>> issuing halt/clear subchannel requests. If it is present, use > >>> it for sending halt/clear request to the device; if not, fall > >>> back to emulation (as done today). > >>> > >>> Signed-off-by: Cornelia Huck <cohuck@redhat.com> > >>> --- > >>> hw/s390x/css.c | 27 +++++++-- > >>> hw/vfio/ccw.c | 109 +++++++++++++++++++++++++++++++++++- > >>> include/hw/s390x/s390-ccw.h | 3 + > >>> 3 files changed, 133 insertions(+), 6 deletions(-) > >>> > > > >>> @@ -114,6 +120,87 @@ again: > >>> } > >>> } > >>> > >>> +int vfio_ccw_handle_clear(SubchDev *sch) > >>> +{ > >>> + S390CCWDevice *cdev = sch->driver_data; > >>> + VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev); > >>> + struct ccw_cmd_region *region = vcdev->async_cmd_region; > >>> + int ret; > >>> + > >>> + if (!vcdev->async_cmd_region) { > >>> + /* Async command region not available, fall back to emulation */ > >>> + return -ENOSYS; > >>> + } > >>> + > >>> + memset(region, 0, sizeof(*region)); > >>> + region->command = VFIO_CCW_ASYNC_CMD_CSCH; > >>> + > >>> +again: > >>> + ret = pwrite(vcdev->vdev.fd, region, > >>> + vcdev->async_cmd_region_size, vcdev->async_cmd_region_offset); > >>> + if (ret != vcdev->async_cmd_region_size) { > >>> + if (errno == EAGAIN) { > >> > >> > >> Where do the EAGAIN come from? > > > > It might be set by pwrite. > > I saw that the man indicate this, and so we are legitimate to handle the > fail case, but I did not find EAGAIN in the path of the write for > accessing devices and I did not find it in the access to the CSS. > > If we do not set it explicitly from the driver, the concern I have is: > isn't it dangerous to try again and shouldn't we better abort? If it is set by the reason stated in the man page, retry sounds like the sensible thing, doesn't it? I don't think I've yet seen it in practice, though. [I don't think we should need to comb through the whole code path to find out what might happen or not, at some point we'll just have to trust the documentation.]
diff --git a/hw/s390x/css.c b/hw/s390x/css.c index 04ec5cc970..0897c041c5 100644 --- a/hw/s390x/css.c +++ b/hw/s390x/css.c @@ -22,6 +22,7 @@ #include "trace.h" #include "hw/s390x/s390_flic.h" #include "hw/s390x/s390-virtio-ccw.h" +#include "hw/s390x/s390-ccw.h" typedef struct CrwContainer { CRW crw; @@ -1194,6 +1195,26 @@ static void sch_handle_start_func_virtual(SubchDev *sch) } +static void sch_handle_halt_func_passthrough(SubchDev *sch) +{ + int ret; + + ret = vfio_ccw_handle_halt(sch); + if (ret == -ENOSYS) { + sch_handle_halt_func(sch); + } +} + +static void sch_handle_clear_func_passthrough(SubchDev *sch) +{ + int ret; + + ret = vfio_ccw_handle_clear(sch); + if (ret == -ENOSYS) { + sch_handle_clear_func(sch); + } +} + static IOInstEnding sch_handle_start_func_passthrough(SubchDev *sch) { @@ -1237,11 +1258,9 @@ IOInstEnding do_subchannel_work_passthrough(SubchDev *sch) SCSW *s = &sch->curr_status.scsw; if (s->ctrl & SCSW_FCTL_CLEAR_FUNC) { - /* TODO: Clear handling */ - sch_handle_clear_func(sch); + sch_handle_clear_func_passthrough(sch); } else if (s->ctrl & SCSW_FCTL_HALT_FUNC) { - /* TODO: Halt handling */ - sch_handle_halt_func(sch); + sch_handle_halt_func_passthrough(sch); } else if (s->ctrl & SCSW_FCTL_START_FUNC) { return sch_handle_start_func_passthrough(sch); } diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c index 9246729a75..dd0fecf168 100644 --- a/hw/vfio/ccw.c +++ b/hw/vfio/ccw.c @@ -2,9 +2,12 @@ * vfio based subchannel assignment support * * Copyright 2017 IBM Corp. + * Copyright 2018 Red Hat, Inc. + * * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> * Xiao Feng Ren <renxiaof@linux.vnet.ibm.com> * Pierre Morel <pmorel@linux.vnet.ibm.com> + * Cornelia Huck <cohuck@redhat.com> * * This work is licensed under the terms of the GNU GPL, version 2 or (at * your option) any later version. See the COPYING file in the top-level @@ -32,6 +35,9 @@ typedef struct VFIOCCWDevice { uint64_t io_region_size; uint64_t io_region_offset; struct ccw_io_region *io_region; + uint64_t async_cmd_region_size; + uint64_t async_cmd_region_offset; + struct ccw_cmd_region *async_cmd_region; EventNotifier io_notifier; bool force_orb_pfch; bool warned_orb_pfch; @@ -114,6 +120,87 @@ again: } } +int vfio_ccw_handle_clear(SubchDev *sch) +{ + S390CCWDevice *cdev = sch->driver_data; + VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev); + struct ccw_cmd_region *region = vcdev->async_cmd_region; + int ret; + + if (!vcdev->async_cmd_region) { + /* Async command region not available, fall back to emulation */ + return -ENOSYS; + } + + memset(region, 0, sizeof(*region)); + region->command = VFIO_CCW_ASYNC_CMD_CSCH; + +again: + ret = pwrite(vcdev->vdev.fd, region, + vcdev->async_cmd_region_size, vcdev->async_cmd_region_offset); + if (ret != vcdev->async_cmd_region_size) { + if (errno == EAGAIN) { + goto again; + } + error_report("vfio-ccw: wirte I/O region failed with errno=%d", errno); + ret = -errno; + } else { + ret = region->ret_code; + } + switch (ret) { + case 0: + case -ENODEV: + case -EACCES: + return 0; + case -EFAULT: + default: + sch_gen_unit_exception(sch); + css_inject_io_interrupt(sch); + return 0; + } +} + +int vfio_ccw_handle_halt(SubchDev *sch) +{ + S390CCWDevice *cdev = sch->driver_data; + VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev); + struct ccw_cmd_region *region = vcdev->async_cmd_region; + int ret; + + if (!vcdev->async_cmd_region) { + /* Async command region not available, fall back to emulation */ + return -ENOSYS; + } + + memset(region, 0, sizeof(*region)); + region->command = VFIO_CCW_ASYNC_CMD_HSCH; + +again: + ret = pwrite(vcdev->vdev.fd, region, + vcdev->async_cmd_region_size, vcdev->async_cmd_region_offset); + if (ret != vcdev->async_cmd_region_size) { + if (errno == EAGAIN) { + goto again; + } + error_report("vfio-ccw: wirte I/O region failed with errno=%d", errno); + ret = -errno; + } else { + ret = region->ret_code; + } + switch (ret) { + case 0: + case -EBUSY: + case -ENODEV: + case -EACCES: + return 0; + case -EFAULT: + default: + sch_gen_unit_exception(sch); + css_inject_io_interrupt(sch); + return 0; + } +} + static void vfio_ccw_reset(DeviceState *dev) { CcwDevice *ccw_dev = DO_UPCAST(CcwDevice, parent_obj, dev); @@ -285,9 +372,13 @@ static void vfio_ccw_get_region(VFIOCCWDevice *vcdev, Error **errp) return; } + /* + * We always expect at least the I/O region to be present. We also + * may have a variable number of regions governed by capabilities. + */ if (vdev->num_regions < VFIO_CCW_CONFIG_REGION_INDEX + 1) { - error_setg(errp, "vfio: Unexpected number of the I/O region %u", - vdev->num_regions); + error_setg(errp, "vfio: too few regions (%u), expected at least %u", + vdev->num_regions, VFIO_CCW_CONFIG_REGION_INDEX + 1); return; } @@ -307,6 +398,20 @@ static void vfio_ccw_get_region(VFIOCCWDevice *vcdev, Error **errp) vcdev->io_region_offset = info->offset; vcdev->io_region = g_malloc0(info->size); + /* check for the optional async command region */ + ret = vfio_get_dev_region_info(vdev, VFIO_REGION_TYPE_CCW, + VFIO_REGION_SUBTYPE_CCW_ASYNC_CMD, &info); + if (!ret) { + vcdev->async_cmd_region_size = info->size; + if (sizeof(*vcdev->async_cmd_region) != vcdev->async_cmd_region_size) { + error_setg(errp, "vfio: Unexpected size of the async cmd region"); + g_free(info); + return; + } + vcdev->async_cmd_region_offset = info->offset; + vcdev->async_cmd_region = g_malloc0(info->size); + } + g_free(info); } diff --git a/include/hw/s390x/s390-ccw.h b/include/hw/s390x/s390-ccw.h index 7d15a1a5d4..38d54a7a69 100644 --- a/include/hw/s390x/s390-ccw.h +++ b/include/hw/s390x/s390-ccw.h @@ -36,4 +36,7 @@ typedef struct S390CCWDeviceClass { IOInstEnding (*handle_request) (SubchDev *sch); } S390CCWDeviceClass; +int vfio_ccw_handle_clear(SubchDev *sch); +int vfio_ccw_handle_halt(SubchDev *sch); + #endif
A vfio-ccw device may provide an async command subregion for issuing halt/clear subchannel requests. If it is present, use it for sending halt/clear request to the device; if not, fall back to emulation (as done today). Signed-off-by: Cornelia Huck <cohuck@redhat.com> --- hw/s390x/css.c | 27 +++++++-- hw/vfio/ccw.c | 109 +++++++++++++++++++++++++++++++++++- include/hw/s390x/s390-ccw.h | 3 + 3 files changed, 133 insertions(+), 6 deletions(-)