On 2018-09-27 00:54, Tony Krowiak wrote:
> Introduces a VFIO based AP device. The device is defined via
> the QEMU command line by specifying:
>
> -device vfio-ap,sysfsdev=<path-to-mediated-matrix-device>
>
> There may be only one vfio-ap device configured for a guest.
>
> The mediated matrix device is created by the VFIO AP device
> driver by writing a UUID to a sysfs attribute file (see
> docs/vfio-ap.txt). The mediated matrix device will be named
> after the UUID. Symbolic links to the $uuid are created in
> many places, so the path to the mediated matrix device $uuid
> can be specified in any of the following ways:
>
> /sys/devices/vfio_ap/matrix/$uuid
> /sys/devices/vfio_ap/matrix/mdev_supported_types/vfio_ap-passthrough/devices/$uuid
> /sys/bus/mdev/devices/$uuid
> /sys/bus/mdev/drivers/vfio_mdev/$uuid
>
> When the vfio-ap device is realized, it acquires and opens the
> VFIO iommu group to which the mediated matrix device is
> bound. This causes a VFIO group notification event to be
> signaled. The vfio_ap device driver's group notification
> handler will get called at which time the device driver
> will configure the the AP devices to which the guest will
> be granted access.
>
> Signed-off-by: Tony Krowiak <akrow...@linux.ibm.com>
> ---
[...]
> diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
> new file mode 100644
> index 000000000000..429988f23f98
> --- /dev/null
> +++ b/hw/vfio/ap.c
> @@ -0,0 +1,181 @@
> +/*
> + * VFIO based AP matrix device assignment
> + *
> + * Copyright 2018 IBM Corp.
> + * Author(s): Tony Krowiak <akrow...@linux.ibm.com>
> + * Halil Pasic <pa...@linux.ibm.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
> + * 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/ap-device.h"
> +#include "qemu/error-report.h"
> +#include "qemu/queue.h"
> +#include "qemu/option.h"
> +#include "qemu/config-file.h"
> +#include "cpu.h"
> +#include "kvm_s390x.h"
> +#include "sysemu/sysemu.h"
> +#include "hw/s390x/ap-bridge.h"
> +#include "exec/address-spaces.h"
> +
> +#define VFIO_AP_DEVICE_TYPE "vfio-ap"
> +
> +typedef struct VFIOAPDevice {
> + APDevice apdev;
> + VFIODevice vdev;
> +} VFIOAPDevice;
> +
> +static void vfio_ap_compute_needs_reset(VFIODevice *vdev)
> +{
> + vdev->needs_reset = false;
> +}
> +
> +/*
> + * We don't need vfio_hot_reset_multi and vfio_eoi operations for
> + * vfio-ap device now.
> + */
> +struct VFIODeviceOps vfio_ap_ops = {
> + .vfio_compute_needs_reset = vfio_ap_compute_needs_reset,
> +};
> +
> +static void vfio_ap_put_device(VFIOAPDevice *vapdev)
> +{
> + g_free(vapdev->vdev.name);
> + vfio_put_base_device(&vapdev->vdev);
> +}
> +
> +static VFIOGroup *vfio_ap_get_group(VFIOAPDevice *vapdev, Error **errp)
> +{
> + char *tmp, group_path[PATH_MAX];
> + ssize_t len;
> + int groupid;
> +
> + tmp = g_strdup_printf("%s/iommu_group", vapdev->vdev.sysfsdev);
> + len = readlink(tmp, group_path, sizeof(group_path));
> + g_free(tmp);
> +
> + if (len <= 0 || len >= sizeof(group_path)) {
> + error_setg(errp, "%s: no iommu_group found for %s",
> + VFIO_AP_DEVICE_TYPE, vapdev->vdev.sysfsdev);
> + return NULL;
> + }
> +
> + group_path[len] = 0;
You could maybe use g_file_read_link() instead to avoid the ugliness
that is needed around readlink().
> + if (sscanf(basename(group_path), "%d", &groupid) != 1) {
> + error_setg(errp, "vfio: failed to read %s", group_path);
> + return NULL;
> + }
> +
> + return vfio_get_group(groupid, &address_space_memory, errp);
> +}
> +
> +static void vfio_ap_realize(DeviceState *dev, Error **errp)
> +{
> + int ret;
> + char *mdevid;
> + Error *local_err = NULL;
> + VFIOGroup *vfio_group;
> + APDevice *apdev = DO_UPCAST(APDevice, parent_obj, dev);
IIRC DO_UPCAST should be avoided in new code. So this is now here the
right place to finally use the AP_DEVICE() macro?
> + VFIOAPDevice *vapdev = DO_UPCAST(VFIOAPDevice, apdev, apdev);
> +
> + vapdev = DO_UPCAST(VFIOAPDevice, apdev, apdev);
Double assignment to vapdev.
> + vfio_group = vfio_ap_get_group(vapdev, &local_err);
> + if (!vfio_group) {
> + goto out_err;
> + }
> +
> + vapdev->vdev.ops = &vfio_ap_ops;
> + vapdev->vdev.type = VFIO_DEVICE_TYPE_AP;
> + mdevid = basename(vapdev->vdev.sysfsdev);
> + vapdev->vdev.name = g_strdup_printf("%s", mdevid);
g_strdup instead of g_strdup_printf should be sufficient here, shouldn't it?
> + vapdev->vdev.dev = dev;
> +
> + ret = vfio_get_device(vfio_group, mdevid, &vapdev->vdev, &local_err);
> + if (ret) {
> + goto out_get_dev_err;
> + }
> +
> + /* Enable hardware to intepret AP instructions executed on the guest */
> + object_property_set_bool(OBJECT(qdev_get_machine()), true, "apie", NULL);
> +
> + return;
> +
> +out_get_dev_err:
> + vfio_ap_put_device(vapdev);
> + vfio_put_group(vfio_group);
> +out_err:
> + error_propagate(errp, local_err);
> +}
Thomas
