sample: vfio mdev display - host device

Simple framebuffer display, demo-ing the vfio region display interface
(VFIO_GFX_PLANE_TYPE_REGION).

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

4 files changed, 838 insertions, 0 deletions

diff --git a/samples/Kconfig b/samples/Kconfig
index 3db002b9e1d3..960f19b24df0 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -115,6 +115,14 @@ config SAMPLE_VFIO_MDEV_MTTY
           Build a virtual tty sample driver for use as a VFIO
           mediated device
 
+config SAMPLE_VFIO_MDEV_MDPY
+        tristate "Build VFIO mdpy example mediated device sample code -- loadable modules only"
+        depends on VFIO_MDEV_DEVICE && m
+        help
+          Build a virtual display sample driver for use as a VFIO
+          mediated device.  It is a simple framebuffer and supports
+          the region display interface (VFIO_GFX_PLANE_TYPE_REGION).
+
 config SAMPLE_STATX
         bool "Build example extended-stat using code"
         depends on BROKEN
diff --git a/samples/vfio-mdev/Makefile b/samples/vfio-mdev/Makefile
index cbbd868a50a8..031d6b88e9e9 100644
--- a/samples/vfio-mdev/Makefile
+++ b/samples/vfio-mdev/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_SAMPLE_VFIO_MDEV_MTTY) += mtty.o
+obj-$(CONFIG_SAMPLE_VFIO_MDEV_MDPY) += mdpy.o
diff --git a/samples/vfio-mdev/mdpy-defs.h b/samples/vfio-mdev/mdpy-defs.h
new file mode 100644
index 000000000000..96b3b1b49d34
--- /dev/null
+++ b/samples/vfio-mdev/mdpy-defs.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Simple pci display device.
+ *
+ * Framebuffer memory is pci bar 0.
+ * Configuration (read-only) is in pci config space.
+ * Format field uses drm fourcc codes.
+ * ATM only DRM_FORMAT_XRGB8888 is supported.
+ */
+
+/* pci ids */
+#define MDPY_PCI_VENDOR_ID      0x1b36 /* redhat */
+#define MDPY_PCI_DEVICE_ID      0x000f
+#define MDPY_PCI_SUBVENDOR_ID   PCI_SUBVENDOR_ID_REDHAT_QUMRANET
+#define MDPY_PCI_SUBDEVICE_ID   PCI_SUBDEVICE_ID_QEMU
+
+/* pci cfg space offsets for fb config (dword) */
+#define MDPY_VENDORCAP_OFFSET   0x40
+#define MDPY_VENDORCAP_SIZE     0x10
+#define MDPY_FORMAT_OFFSET      (MDPY_VENDORCAP_OFFSET + 0x04)
+#define MDPY_WIDTH_OFFSET       (MDPY_VENDORCAP_OFFSET + 0x08)
+#define MDPY_HEIGHT_OFFSET      (MDPY_VENDORCAP_OFFSET + 0x0c)
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
new file mode 100644
index 000000000000..96e7969c473a
--- /dev/null
+++ b/samples/vfio-mdev/mdpy.c
@@ -0,0 +1,807 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Mediated virtual PCI display host device driver
+ *
+ * See mdpy-defs.h for device specs
+ *
+ *   (c) Gerd Hoffmann <kraxel@redhat.com>
+ *
+ * based on mtty driver which is:
+ *   Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *       Author: Neo Jia <cjia@nvidia.com>
+ *               Kirti Wankhede <kwankhede@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/cdev.h>
+#include <linux/vfio.h>
+#include <linux/iommu.h>
+#include <linux/sysfs.h>
+#include <linux/mdev.h>
+#include <linux/pci.h>
+#include <drm/drm_fourcc.h>
+#include "mdpy-defs.h"
+
+#define MDPY_NAME               "mdpy"
+#define MDPY_CLASS_NAME         "mdpy"
+
+#define MDPY_CONFIG_SPACE_SIZE  0xff
+#define MDPY_MEMORY_BAR_OFFSET  PAGE_SIZE
+#define MDPY_DISPLAY_REGION     16
+
+#define STORE_LE16(addr, val)   (*(u16 *)addr = val)
+#define STORE_LE32(addr, val)   (*(u32 *)addr = val)
+
+
+MODULE_LICENSE("GPL v2");
+
+static int max_devices = 4;
+module_param_named(count, max_devices, int, 0444);
+MODULE_PARM_DESC(count, "number of " MDPY_NAME " devices");
+
+
+#define MDPY_TYPE_1 "vga"
+#define MDPY_TYPE_2 "xga"
+#define MDPY_TYPE_3 "hd"
+
+static const struct mdpy_type {
+        const char *name;
+        u32 format;
+        u32 bytepp;
+        u32 width;
+        u32 height;
+} mdpy_types[] = {
+        {
+                .name   = MDPY_CLASS_NAME "-" MDPY_TYPE_1,
+                .format = DRM_FORMAT_XRGB8888,
+                .bytepp = 4,
+                .width  = 640,
+                .height = 480,
+        }, {
+                .name   = MDPY_CLASS_NAME "-" MDPY_TYPE_2,
+                .format = DRM_FORMAT_XRGB8888,
+                .bytepp = 4,
+                .width  = 1024,
+                .height = 768,
+        }, {
+                .name   = MDPY_CLASS_NAME "-" MDPY_TYPE_3,
+                .format = DRM_FORMAT_XRGB8888,
+                .bytepp = 4,
+                .width  = 1920,
+                .height = 1080,
+        },
+};
+
+static dev_t            mdpy_devt;
+static struct class     *mdpy_class;
+static struct cdev      mdpy_cdev;
+static struct device    mdpy_dev;
+static u32              mdpy_count;
+
+/* State of each mdev device */
+struct mdev_state {
+        u8 *vconfig;
+        u32 bar_mask;
+        struct mutex ops_lock;
+        struct mdev_device *mdev;
+        struct vfio_device_info dev_info;
+
+        const struct mdpy_type *type;
+        u32 memsize;
+        void *memblk;
+};
+
+static const struct mdpy_type *mdpy_find_type(struct kobject *kobj)
+{
+        int i;
+
+        for (i = 0; i < ARRAY_SIZE(mdpy_types); i++)
+                if (strcmp(mdpy_types[i].name, kobj->name) == 0)
+                        return mdpy_types + i;
+        return NULL;
+}
+
+static void mdpy_create_config_space(struct mdev_state *mdev_state)
+{
+        STORE_LE16((u16 *) &mdev_state->vconfig[PCI_VENDOR_ID],
+                   MDPY_PCI_VENDOR_ID);
+        STORE_LE16((u16 *) &mdev_state->vconfig[PCI_DEVICE_ID],
+                   MDPY_PCI_DEVICE_ID);
+        STORE_LE16((u16 *) &mdev_state->vconfig[PCI_SUBSYSTEM_VENDOR_ID],
+                   MDPY_PCI_SUBVENDOR_ID);
+        STORE_LE16((u16 *) &mdev_state->vconfig[PCI_SUBSYSTEM_ID],
+                   MDPY_PCI_SUBDEVICE_ID);
+
+        STORE_LE16((u16 *) &mdev_state->vconfig[PCI_COMMAND],
+                   PCI_COMMAND_IO | PCI_COMMAND_MEMORY);
+        STORE_LE16((u16 *) &mdev_state->vconfig[PCI_STATUS],
+                   PCI_STATUS_CAP_LIST);
+        STORE_LE16((u16 *) &mdev_state->vconfig[PCI_CLASS_DEVICE],
+                   PCI_CLASS_DISPLAY_OTHER);
+        mdev_state->vconfig[PCI_CLASS_REVISION] =  0x01;
+
+        STORE_LE32((u32 *) &mdev_state->vconfig[PCI_BASE_ADDRESS_0],
+                   PCI_BASE_ADDRESS_SPACE_MEMORY |
+                   PCI_BASE_ADDRESS_MEM_TYPE_32  |
+                   PCI_BASE_ADDRESS_MEM_PREFETCH);
+        mdev_state->bar_mask = ~(mdev_state->memsize) + 1;
+
+        /* vendor specific capability for the config registers */
+        mdev_state->vconfig[PCI_CAPABILITY_LIST]       = MDPY_VENDORCAP_OFFSET;
+        mdev_state->vconfig[MDPY_VENDORCAP_OFFSET + 0] = 0x09; /* vendor cap */
+        mdev_state->vconfig[MDPY_VENDORCAP_OFFSET + 1] = 0x00; /* next ptr */
+        mdev_state->vconfig[MDPY_VENDORCAP_OFFSET + 2] = MDPY_VENDORCAP_SIZE;
+        STORE_LE32((u32 *) &mdev_state->vconfig[MDPY_FORMAT_OFFSET],
+                   mdev_state->type->format);
+        STORE_LE32((u32 *) &mdev_state->vconfig[MDPY_WIDTH_OFFSET],
+                   mdev_state->type->width);
+        STORE_LE32((u32 *) &mdev_state->vconfig[MDPY_HEIGHT_OFFSET],
+                   mdev_state->type->height);
+}
+
+static void handle_pci_cfg_write(struct mdev_state *mdev_state, u16 offset,
+                                 char *buf, u32 count)
+{
+        struct device *dev = mdev_dev(mdev_state->mdev);
+        u32 cfg_addr;
+
+        switch (offset) {
+        case PCI_BASE_ADDRESS_0:
+                cfg_addr = *(u32 *)buf;