On Wed, 12 Apr 2017 07:21:09 +0200
Dong Jia Shi <bjsdjshi@xxxxxxxxxxxxxxxxxx> wrote:
> From: Xiao Feng Ren <renxiaof@xxxxxxxxxxxxxxxxxx>
>
> We use the IOMMU_TYPE1 of VFIO to realize the subchannels
> passthrough, implement a vfio based subchannels passthrough
> driver called "vfio-ccw".
>
> Support qemu parameters in the style of:
> "-device vfio-ccw,sysfsdev=$mdev_file_path,devno=xx.x.xxxx'
>
> Signed-off-by: Xiao Feng Ren <renxiaof@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Dong Jia Shi <bjsdjshi@xxxxxxxxxxxxxxxxxx>
> ---
> default-configs/s390x-softmmu.mak | 1 +
> hw/vfio/Makefile.objs | 1 +
> hw/vfio/ccw.c | 207 ++++++++++++++++++++++++++++++++++++++
> include/hw/vfio/vfio-common.h | 1 +
> 4 files changed, 210 insertions(+)
> create mode 100644 hw/vfio/ccw.c
>
> diff --git a/default-configs/s390x-softmmu.mak b/default-configs/s390x-softmmu.mak
> index 36e15de..5576b0a 100644
> --- a/default-configs/s390x-softmmu.mak
> +++ b/default-configs/s390x-softmmu.mak
> @@ -4,4 +4,5 @@ CONFIG_VIRTIO=y
> CONFIG_SCLPCONSOLE=y
> CONFIG_S390_FLIC=y
> CONFIG_S390_FLIC_KVM=$(CONFIG_KVM)
> +CONFIG_VFIO_CCW=$(CONFIG_LINUX)
> CONFIG_WDT_DIAG288=y
> diff --git a/hw/vfio/Makefile.objs b/hw/vfio/Makefile.objs
> index 05e7fbb..c3ab909 100644
> --- a/hw/vfio/Makefile.objs
> +++ b/hw/vfio/Makefile.objs
> @@ -1,6 +1,7 @@
> ifeq ($(CONFIG_LINUX), y)
> obj-$(CONFIG_SOFTMMU) += common.o
> obj-$(CONFIG_PCI) += pci.o pci-quirks.o
> +obj-$(CONFIG_VFIO_CCW) += ccw.o
> obj-$(CONFIG_SOFTMMU) += platform.o
> obj-$(CONFIG_VFIO_XGMAC) += calxeda-xgmac.o
> obj-$(CONFIG_VFIO_AMD_XGBE) += amd-xgbe.o
> diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
> new file mode 100644
> index 0000000..c491bee
> --- /dev/null
> +++ b/hw/vfio/ccw.c
> @@ -0,0 +1,207 @@
> +/*
> + * vfio based subchannel assignment support
> + *
> + * Copyright 2017 IBM Corp.
> + * Author(s): Dong Jia Shi <bjsdjshi@xxxxxxxxxxxxxxxxxx>
> + * Xiao Feng Ren <renxiaof@xxxxxxxxxxxxxxxxxx>
> + * Pierre Morel <pmorel@xxxxxxxxxxxxxxxxxx>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or(at
> + * your option) any version. See the COPYING file in the top-level
> + * directory.
> + */
> +
> +#include <linux/vfio.h>
> +#include <sys/ioctl.h>
> +
> +#include "qemu/osdep.h"
> +#include "qapi/error.h"
> +#include "hw/sysbus.h"
> +#include "hw/vfio/vfio.h"
> +#include "hw/vfio/vfio-common.h"
> +#include "hw/s390x/s390-ccw.h"
> +#include "hw/s390x/ccw-device.h"
> +
> +#define TYPE_VFIO_CCW "vfio-ccw"
> +typedef struct VFIOCCWDevice {
> + S390CCWDevice cdev;
> + VFIODevice vdev;
> +} VFIOCCWDevice;
> +
> +static void vfio_ccw_compute_needs_reset(VFIODevice *vdev)
> +{
> + vdev->needs_reset = false;
> +}
> +
> +/*
> + * We don't need vfio_hot_reset_multi and vfio_eoi operationis for
> + * vfio_ccw device now.
> + */
> +struct VFIODeviceOps vfio_ccw_ops = {
> + .vfio_compute_needs_reset = vfio_ccw_compute_needs_reset,
> +};
> +
> +static void vfio_ccw_reset(DeviceState *dev)
> +{
> + CcwDevice *ccw_dev = DO_UPCAST(CcwDevice, parent_obj, dev);
> + S390CCWDevice *cdev = DO_UPCAST(S390CCWDevice, parent_obj, ccw_dev);
> + VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev);
> +
> + ioctl(vcdev->vdev.fd, VFIO_DEVICE_RESET);
> +}
> +
> +static void vfio_put_device(VFIOCCWDevice *vcdev)
> +{
> + g_free(vcdev->vdev.name);
> + vfio_put_base_device(&vcdev->vdev);
> +}
> +
> +static VFIOGroup *vfio_ccw_get_group(S390CCWDevice *cdev, char **path,
> + Error **errp)
> +{
> + struct stat st;
> + int groupid;
> + GError *gerror = NULL;
> +
> + /* Check that host subchannel exists. */
> + path[0] = g_strdup_printf("/sys/bus/css/devices/%x.%x.%04x",
> + cdev->hostid.cssid,
> + cdev->hostid.ssid,
> + cdev->hostid.devid);
> + if (stat(path[0], &st) < 0) {
> + error_setg(errp, "vfio: no such host subchannel %s", path[0]);
> + return NULL;
> + }
> +
> + /* Check that mediated device exists. */
> + path[1] = g_strdup_printf("%s/%s", path[0], cdev->mdevid);
> + if (stat(path[0], &st) < 0) {
> + error_setg(errp, "vfio: no such mediated device %s", path[1]);
> + return NULL;
> + }
Isn't this all a bit circular since we build the S390CCWDevice based on
the sysfsdev mdev path?
> +
> + /* Get the iommu_group patch as the interim variable. */
> + path[2] = g_strconcat(path[1], "/iommu_group", NULL);
> +
> + /* Get the link file path of the device iommu_group. */
> + path[3] = g_file_read_link(path[2], &gerror);
> + if (!path[3]) {
> + error_setg(errp, "vfio: error no iommu_group for subchannel");
> + return NULL;
> + }
> +
> + /* Get the device groupid. */
> + if (sscanf(basename(path[3]), "%d", &groupid) != 1) {
> + error_setg(errp, "vfio: error reading %s:%m", path[3]);
> + return NULL;
> + }
> +
> + return vfio_get_group(groupid, &address_space_memory, errp);
> +}
> +
> +static void vfio_ccw_put_group(VFIOGroup *group, char **path)
> +{
> + g_free(path);
> + vfio_put_group(group);
> +}
> +
> +static void vfio_ccw_realize(DeviceState *dev, Error **errp)
> +{
> + VFIODevice *vbasedev;
> + VFIOGroup *group;
> + CcwDevice *ccw_dev = DO_UPCAST(CcwDevice, parent_obj, dev);
> + S390CCWDevice *cdev = DO_UPCAST(S390CCWDevice, parent_obj, ccw_dev);
> + VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev);
> + S390CCWDeviceClass *cdc = S390_CCW_DEVICE_GET_CLASS(cdev);
> + char *path[4] = {NULL, NULL, NULL, NULL};
I don't understand what's happening with 'path' throughout this
function. vfio_ccw_get_group() allocates strings into this array, we
only seem to use one in an error path below, it's only freed on an error
path and I don't see it getting linked to the VFIOCCWDevice, so it
seems to be leaked, and even the g_free() above looks quite a bit
suspicious.
> +
> + /* Call the class init function for subchannel. */
> + if (cdc->realize) {
> + cdc->realize(cdev, vcdev->vdev.sysfsdev, errp);
> + if (*errp) {
> + return;
> + }
> + }
> +
> + group = vfio_ccw_get_group(cdev, path, errp);
> + if (!group) {
> + goto out_group_err;
> + }
> +
> + vcdev->vdev.ops = &vfio_ccw_ops;
> + vcdev->vdev.type = VFIO_DEVICE_TYPE_CCW;
> + vcdev->vdev.name = g_strdup_printf("%x.%x.%04x", cdev->hostid.cssid,
> + cdev->hostid.ssid, cdev->hostid.devid);
> + QLIST_FOREACH(vbasedev, &group->device_list, next) {
> + if (strcmp(vbasedev->name, vcdev->vdev.name) == 0) {
> + error_setg(errp, "vfio: subchannel %s has already been attached",
> + basename(path[0]));
> + goto out_device_err;
> + }
> + }
> +
> + if (vfio_get_device(group, cdev->mdevid, &vcdev->vdev, errp)) {
> + goto out_device_err;
> + }
> +
> + return;
> +
> +out_device_err:
> + vfio_ccw_put_group(group, path);
> +out_group_err:
> + if (cdc->unrealize) {
> + cdc->unrealize(cdev, errp);
> + }
> +}
> +
> +static void vfio_ccw_unrealize(DeviceState *dev, Error **errp)
> +{
> + CcwDevice *ccw_dev = DO_UPCAST(CcwDevice, parent_obj, dev);
> + S390CCWDevice *cdev = DO_UPCAST(S390CCWDevice, parent_obj, ccw_dev);
> + VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev);
> + S390CCWDeviceClass *cdc = S390_CCW_DEVICE_GET_CLASS(cdev);
> + VFIOGroup *group = vcdev->vdev.group;
> +
> + if (cdc->unrealize) {
> + cdc->unrealize(cdev, errp);
> + }
> +
> + vfio_put_device(vcdev);
> + vfio_put_group(group);
> +}
Doesn't seem to matter here, but I would have expected the
cdc->unrealize to occur at the end to unwind the order of the realize
function.
> +
> +static Property vfio_ccw_properties[] = {
> + DEFINE_PROP_STRING("sysfsdev", VFIOCCWDevice, vdev.sysfsdev),
> + DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static const VMStateDescription vfio_ccw_vmstate = {
> + .name = TYPE_VFIO_CCW,
> + .unmigratable = 1,
> +};
> +
> +static void vfio_ccw_class_init(ObjectClass *klass, void *data)
> +{
> + DeviceClass *dc = DEVICE_CLASS(klass);
> +
> + dc->props = vfio_ccw_properties;
> + dc->vmsd = &vfio_ccw_vmstate;
> + dc->desc = "VFIO-based subchannel assignment";
> + dc->realize = vfio_ccw_realize;
> + dc->unrealize = vfio_ccw_unrealize;
> + dc->reset = vfio_ccw_reset;
> +}
> +
> +static const TypeInfo vfio_ccw_info = {
> + .name = TYPE_VFIO_CCW,
> + .parent = TYPE_S390_CCW,
> + .instance_size = sizeof(VFIOCCWDevice),
> + .class_init = vfio_ccw_class_init,
> +};
> +
> +static void register_vfio_ccw_type(void)
> +{
> + type_register_static(&vfio_ccw_info);
> +}
> +
> +type_init(register_vfio_ccw_type)
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index c582de1..9521013 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -45,6 +45,7 @@
> enum {
> VFIO_DEVICE_TYPE_PCI = 0,
> VFIO_DEVICE_TYPE_PLATFORM = 1,
> + VFIO_DEVICE_TYPE_CCW = 2,
> };
>
> typedef struct VFIOMmap {
