hw/vfio/platform: vfio-platform skeleton

Minimal VFIO platform implementation supporting register space
user mapping but not IRQ assignment.

Signed-off-by: Kim Phillips <kim.phillips@linaro.org>
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Tested-by: Vikram Sethi <vikrams@codeaurora.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 287 insertions, 0 deletions

diff --git a/hw/vfio/platform.c b/hw/vfio/platform.c
new file mode 100644
index 0000000..569a675
--- /dev/null
+++ b/hw/vfio/platform.c
@@ -0,0 +1,287 @@
+/*
+ * vfio based device assignment support - platform devices
+ *
+ * Copyright Linaro Limited, 2014
+ *
+ * Authors:
+ *  Kim Phillips <kim.phillips@linaro.org>
+ *  Eric Auger <eric.auger@linaro.org>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ * Based on vfio based PCI device assignment support:
+ *  Copyright Red Hat, Inc. 2012
+ */
+
+#include <linux/vfio.h>
+#include <sys/ioctl.h>
+
+#include "hw/vfio/vfio-platform.h"
+#include "qemu/error-report.h"
+#include "qemu/range.h"
+#include "sysemu/sysemu.h"
+#include "exec/memory.h"
+#include "hw/sysbus.h"
+#include "trace.h"
+#include "hw/platform-bus.h"
+
+/* VFIO skeleton */
+
+static void vfio_platform_compute_needs_reset(VFIODevice *vbasedev)
+{
+    vbasedev->needs_reset = true;
+}
+
+/* not implemented yet */
+static int vfio_platform_hot_reset_multi(VFIODevice *vbasedev)
+{
+    return -1;
+}
+
+/**
+ * vfio_populate_device - Allocate and populate MMIO region
+ * structs according to driver returned information
+ * @vbasedev: the VFIO device handle
+ *
+ */
+static int vfio_populate_device(VFIODevice *vbasedev)
+{
+    int i, ret = -1;
+    VFIOPlatformDevice *vdev =
+        container_of(vbasedev, VFIOPlatformDevice, vbasedev);
+
+    if (!(vbasedev->flags & VFIO_DEVICE_FLAGS_PLATFORM)) {
+        error_report("vfio: Um, this isn't a platform device");
+        return ret;
+    }
+
+    vdev->regions = g_malloc0_n(vbasedev->num_regions,
+                                sizeof(VFIORegion *));
+
+    for (i = 0; i < vbasedev->num_regions; i++) {
+        struct vfio_region_info reg_info = { .argsz = sizeof(reg_info) };
+        VFIORegion *ptr;
+
+        vdev->regions[i] = g_malloc0(sizeof(VFIORegion));
+        ptr = vdev->regions[i];
+        reg_info.index = i;
+        ret = ioctl(vbasedev->fd, VFIO_DEVICE_GET_REGION_INFO, &reg_info);
+        if (ret) {
+            error_report("vfio: Error getting region %d info: %m", i);
+            goto reg_error;
+        }
+        ptr->flags = reg_info.flags;
+        ptr->size = reg_info.size;
+        ptr->fd_offset = reg_info.offset;
+        ptr->nr = i;
+        ptr->vbasedev = vbasedev;
+
+        trace_vfio_platform_populate_regions(ptr->nr,
+                            (unsigned long)ptr->flags,
+                            (unsigned long)ptr->size,
+                            ptr->vbasedev->fd,
+                            (unsigned long)ptr->fd_offset);
+    }
+
+    return 0;
+reg_error:
+    for (i = 0; i < vbasedev->num_regions; i++) {
+        g_free(vdev->regions[i]);
+    }
+    g_free(vdev->regions);
+    return ret;
+}
+
+/* specialized functions for VFIO Platform devices */
+static VFIODeviceOps vfio_platform_ops = {
+    .vfio_compute_needs_reset = vfio_platform_compute_needs_reset,
+    .vfio_hot_reset_multi = vfio_platform_hot_reset_multi,
+};
+
+/**
+ * vfio_base_device_init - perform preliminary VFIO setup
+ * @vbasedev: the VFIO device handle
+ *
+ * Implement the VFIO command sequence that allows to discover
+ * assigned device resources: group extraction, device
+ * fd retrieval, resource query.
+ * Precondition: the device name must be initialized
+ */
+static int vfio_base_device_init(VFIODevice *vbasedev)
+{
+    VFIOGroup *group;
+    VFIODevice *vbasedev_iter;
+    char path[PATH_MAX], iommu_group_path[PATH_MAX], *group_name;
+    ssize_t len;
+    struct stat st;
+    int groupid;
+    int ret;
+
+    /* name must be set prior to the call */
+    if (!vbasedev->name || strchr(vbasedev->name, '/')) {
+        return -EINVAL;
+    }
+
+    /* Check that the host device exists */
+    g_snprintf(path, sizeof(path), "/sys/bus/platform/devices/%s/",
+               vbasedev->name);
+
+    if (stat(path, &st) < 0) {
+        error_report("vfio: error: no such host device: %s", path);
+        return -errno;
+    }
+
+    g_strlcat(path, "iommu_group", sizeof(path));
+    len = readlink(path, iommu_group_path, sizeof(iommu_group_path));
+    if (len < 0 || len >= sizeof(iommu_group_path)) {
+        error_report("vfio: error no iommu_group for device");
+        return len < 0 ? -errno : -ENAMETOOLONG;
+    }
+
+    iommu_group_path[len] = 0;
+    group_name = basename(iommu_group_path);
+
+    if (sscanf(group_name, "%d", &groupid) != 1) {
+        error_report("vfio: error reading %s: %m", path);
+        return -errno;
+    }
+
+    trace_vfio_platform_base_device_init(vbasedev->name, groupid);
+
+    group = vfio_get_group(groupid, &address_space_memory);
+    if (!group) {
+        error_report("vfio: failed to get group %d", groupid);
+        return -ENOENT;
+    }
+
+    g_snprintf(path, sizeof(path), "%s", vbasedev->name);
+
+    QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
+        if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
+            error_report("vfio: error: device %s is already attached", path);
+            vfio_put_group(group);
+            return -EBUSY;
+        }
+    }
+    ret = vfio_get_device(group, path, vbasedev);
+    if (ret) {
+        error_report("vfio: failed to get device %s", path);
+        vfio_put_group(group);
+        return ret;
+    }
+
+    ret = vfio_populate_device(vbasedev);
+    if (ret) {
+        error_report("vfio: failed to populate device %s", path);
+        vfio_put_group(group);
+    }
+
+    return ret;
+}
+
+/**
+ * vfio_map_region - initialize the 2 memory regions for a given
+ * MMIO region index
+ * @vdev: the VFIO platform device handle
+ * @nr: the index of the region
+ *
+ * Init the top memory region and the mmapped memory region beneath
+ * VFIOPlatformDevice is used since VFIODevice is not a QOM Object
+ * and could not be passed to memory region functions
+*/
+static void vfio_map_region(VFIOPlatformDevice *vdev, int nr)
+{
+    VFIORegion *region = vdev->regions[nr];
+    uint64_t size = region->size;
+    char name[64];
+
+    if (!size) {
+        return;
+    }
+
+    g_snprintf(name, sizeof(name), "VFIO %s region %d",
+               vdev->vbasedev.name, nr);
+
+    /* A "slow" read/write mapping underlies all regions */
+    memory_region_init_io(&region->mem, OBJECT(vdev), &vfio_region_ops,
+                          region, name, size);
+
+    g_strlcat(name, " mmap", sizeof(name));
+
+    if (vfio_mmap_region(OBJECT(vdev), region, &region->mem,
+                         &region->mmap_mem, &region->mmap, size, 0, name)) {
+        error_report("%s unsupported. Performance may be slow", name);
+    }
+}
+
+/**
+ * vfio_platform_realize  - the device realize function
+ * @dev: device state pointer
+ * @errp: error
+ *
+ * initialize the device, its memory regions and IRQ structures
+ * IRQ are started separately
+ */
+static void vfio_platform_realize(DeviceState *dev, Error **errp)
+{
+    VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(dev);
+    SysBusDevice *sbdev = SYS_BUS_DEVICE(dev);
+    VFIODevice *vbasedev = &vdev->vbasedev;
+    int i, ret;
+
+    vbasedev->type = VFIO_DEVICE_TYPE_PLATFORM;
+    vbasedev->ops = &vfio_platform_ops;
+
+    trace_vfio_platform_realize(vbasedev->name, vdev->compat);
+
+    ret = vfio_base_device_init(vbasedev);
+    if (ret) {
+        error_setg(errp, "vfio: vfio_base_device_init failed for %s",
+                   vbasedev->name);
+        return;
+    }
+
+    for (i = 0; i < vbasedev->num_regions; i++) {
+        vfio_map_region(vdev, i);
+        sysbus_init_mmio(sbdev, &vdev->regions[i]->mem);
+    }
+}
+
+static const VMStateDescription vfio_platform_vmstate = {
+    .name = TYPE_VFIO_PLATFORM,
+    .unmigratable = 1,
+};
+
+static Property vfio_platform_dev_properties[] = {
+    DEFINE_PROP_STRING("host", VFIOPlatformDevice, vbasedev.name),
+    DEFINE_PROP_BOOL("x-mmap", VFIOPlatformDevice, vbasedev.allow_mmap, true),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void vfio_platform_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->realize = vfio_platform_realize;
+    dc->props = vfio_platform_dev_properties;
+    dc->vmsd = &vfio_platform_vmstate;
+    dc->desc = "VFIO-based platform device assignment";
+    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+}
+
+static const TypeInfo vfio_platform_dev_info = {
+    .name = TYPE_VFIO_PLATFORM,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(VFIOPlatformDevice),
+    .class_init = vfio_platform_class_init,
+    .class_size = sizeof(VFIOPlatformDeviceClass),
+    .abstract   = true,
+};
+
+static void register_vfio_platform_dev_type(void)
+{
+    type_register_static(&vfio_platform_dev_info);
+}
+
+type_init(register_vfio_platform_dev_type)