Introduces hot plug/unplug support for the vfio-ap device. To hot plug a vfio-ap device using the QEMU device_add command: (qemu) device_add vfio-ap,sysfsdev=$path-to-mdev Where $path-to-mdev is the absolute path to the mediated matrix device to which AP resources to be used by the guest have been assigned. A vfio-ap device can be hot plugged only if: 1. A vfio-ap device has not been attached to the virtual machine's ap-bus via the QEMU command line or a prior hot plug action. 2. The guest was started with the CPU model feature for AP enabled (e.g., -cpu host,ap=on) To hot unplug a vfio-ap device using the QEMU device_del command: (qemu) device_del vfio-ap,sysfsdev=$path-to-mdev Where $path-to-mdev is the absolute path to the mediated matrix device specified when the vfio-ap device was attached to the virtual machine's ap-bus. A vfio-ap device can be hot unplugged only if: 1. A vfio-ap device has been attached to the virtual machine's ap-bus via the QEMU command line or a prior hot plug action. 2. The guest was started with the CPU model feature for AP enabled (e.g., -cpu host,ap=on) Please note that a hot plug handler is not necessary for the vfio-ap device because the AP matrix configuration for the guest is performed by the kernel device driver when the vfio-ap device is realized. The vfio-ap device represents a VFIO mediated device created in the host sysfs for use by a guest. The mdev device is configured with an AP matrix (i.e., adapters and domains) via its sysfs attribute interfaces prior to starting the guest or plugging a vfio-ap device in. When the device is realized, a file descriptor is opened on the mdev device which results in a callback to the vfio_ap kernel device driver. The device driver then configures the AP matrix in the guest's SIE state description from the AP matrix assigned via the mdev device's sysfs interfaces. The AP devices will be created for the guest when the AP bus running on the guest subsequently performs its periodic scan for AP devices. The qdev_simple_device_unplug_cb() callback function is used for the same reaons; namely, the vfio_ap kernel device driver will perform the AP resource de-configuration for the guest when the vfio-ap device is unplugged. When the vfio-ap device is unrealized, the mdev device file descriptor is closed which results in a callback to the vfio_ap kernel device driver. The device driver then clears the AP matrix configuration in the guest's SIE state description and resets all of the affected queues. The AP devices created for the guest will be removed when the AP bus running on the guest subsequently performs its periodic scan and finds there are no longer any AP resources assigned to the guest. Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com> Reviewed-by: Pierre Morel <pmorel@linux.ibm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Halil Pasic <pasic@linux.ibm.com> Tested-by: Pierre Morel <pmorel@linux.ibm.com> Message-Id: <1550519397-25359-2-git-send-email-akrowiak@linux.ibm.com> [CH: adapt to changed qbus_set_hotplug_handler() signature] Signed-off-by: Cornelia Huck <cohuck@redhat.com>
190 lines
4.8 KiB
C
190 lines
4.8 KiB
C
/*
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* VFIO based AP matrix device assignment
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*
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* Copyright 2018 IBM Corp.
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* Author(s): Tony Krowiak <akrowiak@linux.ibm.com>
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* Halil Pasic <pasic@linux.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or (at
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* your option) any later version. See the COPYING file in the top-level
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* directory.
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*/
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#include "qemu/osdep.h"
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#include <linux/vfio.h>
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#include <sys/ioctl.h>
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#include "qapi/error.h"
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#include "hw/sysbus.h"
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#include "hw/vfio/vfio.h"
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#include "hw/vfio/vfio-common.h"
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#include "hw/s390x/ap-device.h"
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#include "qemu/error-report.h"
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#include "qemu/queue.h"
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#include "qemu/option.h"
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#include "qemu/config-file.h"
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#include "cpu.h"
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#include "kvm_s390x.h"
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#include "sysemu/sysemu.h"
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#include "hw/s390x/ap-bridge.h"
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#include "exec/address-spaces.h"
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#define VFIO_AP_DEVICE_TYPE "vfio-ap"
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typedef struct VFIOAPDevice {
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APDevice apdev;
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VFIODevice vdev;
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} VFIOAPDevice;
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#define VFIO_AP_DEVICE(obj) \
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OBJECT_CHECK(VFIOAPDevice, (obj), VFIO_AP_DEVICE_TYPE)
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static void vfio_ap_compute_needs_reset(VFIODevice *vdev)
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{
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vdev->needs_reset = false;
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}
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/*
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* We don't need vfio_hot_reset_multi and vfio_eoi operations for
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* vfio-ap device now.
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*/
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struct VFIODeviceOps vfio_ap_ops = {
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.vfio_compute_needs_reset = vfio_ap_compute_needs_reset,
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};
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static void vfio_ap_put_device(VFIOAPDevice *vapdev)
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{
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g_free(vapdev->vdev.name);
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vfio_put_base_device(&vapdev->vdev);
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}
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static VFIOGroup *vfio_ap_get_group(VFIOAPDevice *vapdev, Error **errp)
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{
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GError *gerror = NULL;
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char *symlink, *group_path;
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int groupid;
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symlink = g_strdup_printf("%s/iommu_group", vapdev->vdev.sysfsdev);
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group_path = g_file_read_link(symlink, &gerror);
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g_free(symlink);
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if (!group_path) {
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error_setg(errp, "%s: no iommu_group found for %s: %s",
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VFIO_AP_DEVICE_TYPE, vapdev->vdev.sysfsdev, gerror->message);
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return NULL;
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}
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if (sscanf(basename(group_path), "%d", &groupid) != 1) {
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error_setg(errp, "vfio: failed to read %s", group_path);
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g_free(group_path);
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return NULL;
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}
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g_free(group_path);
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return vfio_get_group(groupid, &address_space_memory, errp);
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}
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static void vfio_ap_realize(DeviceState *dev, Error **errp)
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{
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int ret;
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char *mdevid;
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Error *local_err = NULL;
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VFIOGroup *vfio_group;
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APDevice *apdev = AP_DEVICE(dev);
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VFIOAPDevice *vapdev = VFIO_AP_DEVICE(apdev);
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vfio_group = vfio_ap_get_group(vapdev, &local_err);
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if (!vfio_group) {
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goto out_err;
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}
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vapdev->vdev.ops = &vfio_ap_ops;
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vapdev->vdev.type = VFIO_DEVICE_TYPE_AP;
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mdevid = basename(vapdev->vdev.sysfsdev);
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vapdev->vdev.name = g_strdup_printf("%s", mdevid);
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vapdev->vdev.dev = dev;
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/*
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* vfio-ap devices operate in a way compatible with
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* memory ballooning, as no pages are pinned in the host.
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* This needs to be set before vfio_get_device() for vfio common to
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* handle the balloon inhibitor.
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*/
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vapdev->vdev.balloon_allowed = true;
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ret = vfio_get_device(vfio_group, mdevid, &vapdev->vdev, &local_err);
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if (ret) {
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goto out_get_dev_err;
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}
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return;
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out_get_dev_err:
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vfio_ap_put_device(vapdev);
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vfio_put_group(vfio_group);
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out_err:
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error_propagate(errp, local_err);
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}
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static void vfio_ap_unrealize(DeviceState *dev, Error **errp)
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{
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APDevice *apdev = AP_DEVICE(dev);
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VFIOAPDevice *vapdev = VFIO_AP_DEVICE(apdev);
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VFIOGroup *group = vapdev->vdev.group;
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vfio_ap_put_device(vapdev);
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vfio_put_group(group);
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}
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static Property vfio_ap_properties[] = {
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DEFINE_PROP_STRING("sysfsdev", VFIOAPDevice, vdev.sysfsdev),
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DEFINE_PROP_END_OF_LIST(),
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};
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static void vfio_ap_reset(DeviceState *dev)
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{
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int ret;
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APDevice *apdev = AP_DEVICE(dev);
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VFIOAPDevice *vapdev = VFIO_AP_DEVICE(apdev);
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ret = ioctl(vapdev->vdev.fd, VFIO_DEVICE_RESET);
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if (ret) {
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error_report("%s: failed to reset %s device: %s", __func__,
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vapdev->vdev.name, strerror(errno));
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}
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}
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static const VMStateDescription vfio_ap_vmstate = {
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.name = VFIO_AP_DEVICE_TYPE,
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.unmigratable = 1,
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};
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static void vfio_ap_class_init(ObjectClass *klass, void *data)
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{
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DeviceClass *dc = DEVICE_CLASS(klass);
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dc->props = vfio_ap_properties;
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dc->vmsd = &vfio_ap_vmstate;
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dc->desc = "VFIO-based AP device assignment";
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set_bit(DEVICE_CATEGORY_MISC, dc->categories);
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dc->realize = vfio_ap_realize;
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dc->unrealize = vfio_ap_unrealize;
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dc->hotpluggable = true;
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dc->reset = vfio_ap_reset;
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dc->bus_type = TYPE_AP_BUS;
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}
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static const TypeInfo vfio_ap_info = {
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.name = VFIO_AP_DEVICE_TYPE,
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.parent = AP_DEVICE_TYPE,
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.instance_size = sizeof(VFIOAPDevice),
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.class_init = vfio_ap_class_init,
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};
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static void vfio_ap_type_init(void)
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{
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type_register_static(&vfio_ap_info);
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}
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type_init(vfio_ap_type_init)
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