xen, gfx passthrough: basic graphics passthrough support

basic gfx passthrough support:
- add a vga type for gfx passthrough
- register/unregister legacy VGA I/O ports and MMIOs for passthrough GFX

Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

hw/core/machine.c

@@ -226,6 +226,20 @@ static void machine_set_usb(Object *obj, bool value, Error **errp)
     ms->usb_disabled = !value;
 }
 
+static bool machine_get_igd_gfx_passthru(Object *obj, Error **errp)
+{
+    MachineState *ms = MACHINE(obj);
+
+    return ms->igd_gfx_passthru;
+}
+
+static void machine_set_igd_gfx_passthru(Object *obj, bool value, Error **errp)
+{
+    MachineState *ms = MACHINE(obj);
+
+    ms->igd_gfx_passthru = value;
+}
+
 static char *machine_get_firmware(Object *obj, Error **errp)
 {
     MachineState *ms = MACHINE(obj);
@@ -388,6 +402,12 @@ static void machine_initfn(Object *obj)
     object_property_set_description(obj, "usb",
                                     "Set on/off to enable/disable usb",
                                     NULL);
+    object_property_add_bool(obj, "igd-passthru",
+                             machine_get_igd_gfx_passthru,
+                             machine_set_igd_gfx_passthru, NULL);
+    object_property_set_description(obj, "igd-passthru",
+                                    "Set on/off to enable/disable igd passthrou",
+                                    NULL);
     object_property_add_str(obj, "firmware",
                             machine_get_firmware,
                             machine_set_firmware, NULL);

hw/xen/Makefile.objs

@@ -3,3 +3,4 @@ common-obj-$(CONFIG_XEN_BACKEND) += xen_backend.o xen_devconfig.o
 
 obj-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen-host-pci-device.o
 obj-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen_pt.o xen_pt_config_init.o xen_pt_msi.o
+obj-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen_pt.o xen_pt_config_init.o xen_pt_msi.o xen_pt_graphics.o

hw/xen/xen-host-pci-device.c

@@ -376,6 +376,11 @@ int xen_host_pci_device_get(XenHostPCIDevice *d, uint16_t domain,
         goto error;
     }
     d->irq = v;
+    rc = xen_host_pci_get_hex_value(d, "class", &v);
+    if (rc) {
+        goto error;
+    }
+    d->class_code = v;
     d->is_virtfn = xen_host_pci_dev_is_virtfn(d);
 
     return 0;

hw/xen/xen-host-pci-device.h

@@ -25,6 +25,7 @@ typedef struct XenHostPCIDevice {
 
     uint16_t vendor_id;
     uint16_t device_id;
+    uint32_t class_code;
     int irq;
 
     XenHostPCIIORegion io_regions[PCI_NUM_REGIONS - 1];

hw/xen/xen_pt.c

@@ -502,6 +502,7 @@ static int xen_pt_register_regions(XenPCIPassthroughState *s, uint16_t *cmd)
                    d->rom.size, d->rom.base_addr);
     }
 
+    xen_pt_register_vga_regions(d);
     return 0;
 }
 
@@ -801,6 +802,7 @@ out:
 static void xen_pt_unregister_device(PCIDevice *d)
 {
     XenPCIPassthroughState *s = XEN_PT_DEVICE(d);
+    XenHostPCIDevice *host_dev = &s->real_device;
     uint8_t machine_irq = s->machine_irq;
     uint8_t intx = xen_pt_pci_intx(s);
     int rc;
@@ -844,6 +846,8 @@ static void xen_pt_unregister_device(PCIDevice *d)
     /* delete all emulated config registers */
     xen_pt_config_delete(s);
 
+    xen_pt_unregister_vga_regions(host_dev);
+
     memory_listener_unregister(&s->memory_listener);
     memory_listener_unregister(&s->io_listener);
 

hw/xen/xen_pt.h

@@ -305,5 +305,13 @@ static inline bool xen_pt_has_msix_mapping(XenPCIPassthroughState *s, int bar)
     return s->msix && s->msix->bar_index == bar;
 }
 
-
+extern bool has_igd_gfx_passthru;
+static inline bool is_igd_vga_passthrough(XenHostPCIDevice *dev)
+{
+    return (has_igd_gfx_passthru
+            && ((dev->class_code >> 0x8) == PCI_CLASS_DISPLAY_VGA));
+}
+int xen_pt_register_vga_regions(XenHostPCIDevice *dev);
+int xen_pt_unregister_vga_regions(XenHostPCIDevice *dev);
+int xen_pt_setup_vga(XenPCIPassthroughState *s, XenHostPCIDevice *dev);
 #endif /* !XEN_PT_H */

hw/xen/xen_pt_graphics.c

@@ -0,0 +1,111 @@
+/*
+ * graphics passthrough
+ */
+#include "xen_pt.h"
+#include "xen-host-pci-device.h"
+#include "hw/xen/xen_backend.h"
+
+typedef struct VGARegion {
+    int type;           /* Memory or port I/O */
+    uint64_t guest_base_addr;
+    uint64_t machine_base_addr;
+    uint64_t size;    /* size of the region */
+    int rc;
+} VGARegion;
+
+#define IORESOURCE_IO           0x00000100
+#define IORESOURCE_MEM          0x00000200
+
+static struct VGARegion vga_args[] = {
+    {
+        .type = IORESOURCE_IO,
+        .guest_base_addr = 0x3B0,
+        .machine_base_addr = 0x3B0,
+        .size = 0xC,
+        .rc = -1,
+    },
+    {
+        .type = IORESOURCE_IO,
+        .guest_base_addr = 0x3C0,
+        .machine_base_addr = 0x3C0,
+        .size = 0x20,
+        .rc = -1,
+    },
+    {
+        .type = IORESOURCE_MEM,
+        .guest_base_addr = 0xa0000 >> XC_PAGE_SHIFT,
+        .machine_base_addr = 0xa0000 >> XC_PAGE_SHIFT,
+        .size = 0x20,
+        .rc = -1,
+    },
+};
+
+/*
+ * register VGA resources for the domain with assigned gfx
+ */
+int xen_pt_register_vga_regions(XenHostPCIDevice *dev)
+{
+    int i = 0;
+
+    if (!is_igd_vga_passthrough(dev)) {
+        return 0;
+    }
+
+    for (i = 0 ; i < ARRAY_SIZE(vga_args); i++) {
+        if (vga_args[i].type == IORESOURCE_IO) {
+            vga_args[i].rc = xc_domain_ioport_mapping(xen_xc, xen_domid,
+                            vga_args[i].guest_base_addr,
+                            vga_args[i].machine_base_addr,
+                            vga_args[i].size, DPCI_ADD_MAPPING);
+        } else {
+            vga_args[i].rc = xc_domain_memory_mapping(xen_xc, xen_domid,
+                            vga_args[i].guest_base_addr,
+                            vga_args[i].machine_base_addr,
+                            vga_args[i].size, DPCI_ADD_MAPPING);
+        }
+
+        if (vga_args[i].rc) {
+            XEN_PT_ERR(NULL, "VGA %s mapping failed! (rc: %i)\n",
+                    vga_args[i].type == IORESOURCE_IO ? "ioport" : "memory",
+                    vga_args[i].rc);
+            return vga_args[i].rc;
+        }
+    }
+
+    return 0;
+}
+
+/*
+ * unregister VGA resources for the domain with assigned gfx
+ */
+int xen_pt_unregister_vga_regions(XenHostPCIDevice *dev)
+{
+    int i = 0;
+
+    if (!is_igd_vga_passthrough(dev)) {
+        return 0;
+    }
+
+    for (i = 0 ; i < ARRAY_SIZE(vga_args); i++) {
+        if (vga_args[i].type == IORESOURCE_IO) {
+            vga_args[i].rc = xc_domain_ioport_mapping(xen_xc, xen_domid,
+                            vga_args[i].guest_base_addr,
+                            vga_args[i].machine_base_addr,
+                            vga_args[i].size, DPCI_REMOVE_MAPPING);
+        } else {
+            vga_args[i].rc = xc_domain_memory_mapping(xen_xc, xen_domid,
+                            vga_args[i].guest_base_addr,
+                            vga_args[i].machine_base_addr,
+                            vga_args[i].size, DPCI_REMOVE_MAPPING);
+        }
+
+        if (vga_args[i].rc) {
+            XEN_PT_ERR(NULL, "VGA %s unmapping failed! (rc: %i)\n",
+                    vga_args[i].type == IORESOURCE_IO ? "ioport" : "memory",
+                    vga_args[i].rc);
+            return vga_args[i].rc;
+        }
+    }
+
+    return 0;
+}

include/hw/boards.h

@@ -137,6 +137,7 @@ struct MachineState {
     bool mem_merge;
     bool usb;
     bool usb_disabled;
+    bool igd_gfx_passthru;
     char *firmware;
     bool iommu;
     bool suppress_vmdesc;

qemu-options.hx

@@ -38,6 +38,7 @@ DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
     "                dump-guest-core=on|off include guest memory in a core dump (default=on)\n"
     "                mem-merge=on|off controls memory merge support (default: on)\n"
     "                iommu=on|off controls emulated Intel IOMMU (VT-d) support (default=off)\n"
+    "                igd-passthru=on|off controls IGD GFX passthrough support (default=off)\n"
     "                aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n"
     "                dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n"
     "                suppress-vmdesc=on|off disables self-describing migration (default=off)\n",
@@ -55,6 +56,8 @@ than one accelerator specified, the next one is used if the previous one fails
 to initialize.
 @item kernel_irqchip=on|off
 Enables in-kernel irqchip support for the chosen accelerator when available.
+@item gfx_passthru=on|off
+Enables IGD GFX passthrough support for the chosen machine when available.
 @item vmport=on|off|auto
 Enables emulation of VMWare IO port, for vmmouse etc. auto says to select the
 value based on accel. For accel=xen the default is off otherwise the default

vl.c

@@ -1338,6 +1338,13 @@ static inline void semihosting_arg_fallback(const char *file, const char *cmd)
     }
 }
 
+/* Now we still need this for compatibility with XEN. */
+bool has_igd_gfx_passthru;
+static void igd_gfx_passthru(void)
+{
+    has_igd_gfx_passthru = current_machine->igd_gfx_passthru;
+}
+
 /***********************************************************/
 /* USB devices */
 
@@ -4528,6 +4535,9 @@ int main(int argc, char **argv, char **envp)
             exit(1);
     }
 
+    /* Check if IGD GFX passthrough. */
+    igd_gfx_passthru();
+
     /* init generic devices */
     if (qemu_opts_foreach(qemu_find_opts("device"),
                           device_init_func, NULL, NULL)) {