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Re: [qemu-s390x] [PATCH v10 5/6] s390x/vfio: ap: Introduce VFIO AP devic


From: Tony Krowiak
Subject: Re: [qemu-s390x] [PATCH v10 5/6] s390x/vfio: ap: Introduce VFIO AP device
Date: Wed, 10 Oct 2018 10:12:47 -0400
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0

On 10/10/2018 04:25 AM, Thomas Huth wrote:
On 2018-10-09 19:52, 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 <address@hidden>
Tested-by: Pierre Morel<address@hidden>
---
[...]
+static VFIOGroup *vfio_ap_get_group(VFIOAPDevice *vapdev, Error **errp)
+{
+    GError *gerror;
+    char *symlink, *group_path;
+    int groupid;
+
+    symlink = g_strdup_printf("%s/iommu_group", vapdev->vdev.sysfsdev);
+    group_path = g_file_read_link(symlink, &gerror);
+    g_free(symlink);
+
+    if (!group_path) {
+        error_setg(errp, "%s: no iommu_group found for %s: %s",
+                   VFIO_AP_DEVICE_TYPE, vapdev->vdev.sysfsdev, 
gerror->message);
+        return NULL;
+    }
+
+    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);
+}

I think you've got to g_free(group_path) after you don't need it anymore.

Right you are.


+static void vfio_ap_realize(DeviceState *dev, Error **errp)
+{
+    int ret;
+    char *mdevid;
+    Error *local_err = NULL;
+    VFIOGroup *vfio_group;
+    APDevice *apdev = AP_DEVICE(dev);
+    VFIOAPDevice *vapdev = VFIO_AP_DEVICE(apdev);
+
+    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);
+    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);
+}
+
+static void vfio_ap_unrealize(DeviceState *dev, Error **errp)
+{
+    APDevice *apdev = DO_UPCAST(APDevice, parent_obj, dev);
+    VFIOAPDevice *vapdev = DO_UPCAST(VFIOAPDevice, apdev, apdev);

Didn't you want to remove the DO_UPCASTs ?

oops, missed these .... fixed them in the realize function, but
missed this one and the next .... will fix


+    VFIOGroup *group = vapdev->vdev.group;
+
+    vfio_ap_put_device(vapdev);
+    vfio_put_group(group);
+}
+
+static Property vfio_ap_properties[] = {
+    DEFINE_PROP_STRING("sysfsdev", VFIOAPDevice, vdev.sysfsdev),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void vfio_ap_reset(DeviceState *dev)
+{
+    int ret;
+    APDevice *apdev = DO_UPCAST(APDevice, parent_obj, dev);
+    VFIOAPDevice *vapdev = DO_UPCAST(VFIOAPDevice, apdev, apdev);

dito

ditto


+    ret = ioctl(vapdev->vdev.fd, VFIO_DEVICE_RESET);
+    if (ret) {
+        error_report("%s: failed to reset %s device: %s", __func__,
+                     vapdev->vdev.name, strerror(ret));
+    }
+}

  Thomas





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