[Qemu-devel] [PATCH 1/5] xen, gfx passthrough: basic graphics passthrough support

[Yang Zhang <yang.z.zhang@intel.com>]

From: Yang Zhang <yang.z.zhang@Intel.com>

basic gfx passthrough support:
- add a vga type for gfx passthrough
- retrieve VGA bios from host 0xC0000, then load it to guest 0xC0000
- register/unregister legacy VGA I/O ports and MMIOs for passthroughed gfx

The original patch is from Weidong Han <weidong.han@intel.com>

Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Cc: Weidong Han <weidong.han@intel.com>
---
 configure                    |    2 +-
 hw/xen/Makefile.objs         |    2 +-
 hw/xen/xen-host-pci-device.c |    5 ++
 hw/xen/xen-host-pci-device.h |    1 +
 hw/xen/xen_pt.c              |   10 +++
 hw/xen/xen_pt.h              |    4 +
 hw/xen/xen_pt_graphics.c     |  164 ++++++++++++++++++++++++++++++++++++++++++
 qemu-options.hx              |    9 +++
 vl.c                         |    8 ++
 9 files changed, 203 insertions(+), 2 deletions(-)
 create mode 100644 hw/xen/xen_pt_graphics.c

diff --git a/configure b/configure
index 4648117..19525ab 100755
--- a/configure
+++ b/configure
@@ -4608,7 +4608,7 @@ case "$target_name" in
     if test "$xen" = "yes" -a "$target_softmmu" = "yes" ; then
       echo "CONFIG_XEN=y" >> $config_target_mak
       if test "$xen_pci_passthrough" = yes; then
-        echo "CONFIG_XEN_PCI_PASSTHROUGH=y" >> "$config_target_mak"
+        echo "CONFIG_XEN_PCI_PASSTHROUGH=y" >> "$config_host_mak"
       fi
     fi
     ;;
diff --git a/hw/xen/Makefile.objs b/hw/xen/Makefile.objs
index ce640c6..350d337 100644
--- a/hw/xen/Makefile.objs
+++ b/hw/xen/Makefile.objs
@@ -3,4 +3,4 @@ common-obj-$(CONFIG_XEN_BACKEND) += xen_backend.o xen_devconfig.o
 
 obj-$(CONFIG_XEN_I386) += xen_platform.o xen_apic.o xen_pvdevice.o
 obj-$(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
diff --git a/hw/xen/xen-host-pci-device.c b/hw/xen/xen-host-pci-device.c
index 743b37b..a54b7de 100644
--- a/hw/xen/xen-host-pci-device.c
+++ b/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;
diff --git a/hw/xen/xen-host-pci-device.h b/hw/xen/xen-host-pci-device.h
index c2486f0..f1e1c30 100644
--- a/hw/xen/xen-host-pci-device.h
+++ b/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];
diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
index be4220b..5a36902 100644
--- a/hw/xen/xen_pt.c
+++ b/hw/xen/xen_pt.c
@@ -450,6 +450,7 @@ static int xen_pt_register_regions(XenPCIPassthroughState *s)
                    d->rom.size, d->rom.base_addr);
     }
 
+    register_vga_regions(d);
     return 0;
 }
 
@@ -470,6 +471,8 @@ static void xen_pt_unregister_regions(XenPCIPassthroughState *s)
     if (d->rom.base_addr && d->rom.size) {
         memory_region_destroy(&s->rom);
     }
+
+    unregister_vga_regions(d);
 }
 
 /* region mapping */
@@ -693,6 +696,13 @@ static int xen_pt_initfn(PCIDevice *d)
     /* Handle real device's MMIO/PIO BARs */
     xen_pt_register_regions(s);
 
+    /* Setup VGA bios for passthroughed gfx */
+    if (setup_vga_pt(&s->real_device) < 0) {
+        XEN_PT_ERR(d, "Setup VGA BIOS of passthroughed gfx failed!\n");
+        xen_host_pci_device_put(&s->real_device);
+        return -1;
+    }
+
     /* reinitialize each config register to be emulated */
     if (xen_pt_config_init(s)) {
         XEN_PT_ERR(d, "PCI Config space initialisation failed.\n");
diff --git a/hw/xen/xen_pt.h b/hw/xen/xen_pt.h
index 942dc60..c04bbfd 100644
--- a/hw/xen/xen_pt.h
+++ b/hw/xen/xen_pt.h
@@ -298,5 +298,9 @@ static inline bool xen_pt_has_msix_mapping(XenPCIPassthroughState *s, int bar)
     return s->msix && s->msix->bar_index == bar;
 }
 
+extern int gfx_passthru;
+int register_vga_regions(XenHostPCIDevice *dev);
+int unregister_vga_regions(XenHostPCIDevice *dev);
+int setup_vga_pt(XenHostPCIDevice *dev);
 
 #endif /* !XEN_PT_H */
diff --git a/hw/xen/xen_pt_graphics.c b/hw/xen/xen_pt_graphics.c
new file mode 100644
index 0000000..9ad8a74
--- /dev/null
+++ b/hw/xen/xen_pt_graphics.c
@@ -0,0 +1,164 @@
+/*
+ * graphics passthrough
+ */
+#include "xen_pt.h"
+#include "xen-host-pci-device.h"
+#include "hw/xen/xen_backend.h"
+
+/*
+ * register VGA resources for the domain with assigned gfx
+ */
+int register_vga_regions(XenHostPCIDevice *dev)
+{
+    int ret = 0;
+
+    if (!gfx_passthru || ((dev->class_code >> 0x8) != 0x0300)) {
+        return ret;
+    }
+
+    ret |= xc_domain_ioport_mapping(xen_xc, xen_domid, 0x3B0,
+            0x3B0, 0xA, DPCI_ADD_MAPPING);
+
+    ret |= xc_domain_ioport_mapping(xen_xc, xen_domid, 0x3C0,
+            0x3C0, 0x20, DPCI_ADD_MAPPING);
+
+    ret |= xc_domain_memory_mapping(xen_xc, xen_domid,
+            0xa0000 >> XC_PAGE_SHIFT,
+            0xa0000 >> XC_PAGE_SHIFT,
+            0x20,
+            DPCI_ADD_MAPPING);
+
+    if (ret != 0) {
+        XEN_PT_ERR(NULL, "VGA region mapping failed\n");
+    }
+
+    return ret;
+}
+
+/*
+ * unregister VGA resources for the domain with assigned gfx
+ */
+int unregister_vga_regions(XenHostPCIDevice *dev)
+{
+    int ret = 0;
+
+    if (!gfx_passthru || ((dev->class_code >> 0x8) != 0x0300)) {
+        return ret;
+    }
+
+    ret |= xc_domain_ioport_mapping(xen_xc, xen_domid, 0x3B0,
+            0x3B0, 0xC, DPCI_REMOVE_MAPPING);
+
+    ret |= xc_domain_ioport_mapping(xen_xc, xen_domid, 0x3C0,
+            0x3C0, 0x20, DPCI_REMOVE_MAPPING);
+
+    ret |= xc_domain_memory_mapping(xen_xc, xen_domid,
+            0xa0000 >> XC_PAGE_SHIFT,
+            0xa0000 >> XC_PAGE_SHIFT,
+            20,
+            DPCI_REMOVE_MAPPING);
+
+    if (ret != 0) {
+        XEN_PT_ERR(NULL, "VGA region unmapping failed\n");
+    }
+
+    return ret;
+}
+
+static int get_vgabios(unsigned char *buf)
+{
+    int fd;
+    uint32_t bios_size = 0;
+    uint32_t start = 0xC0000;
+    uint16_t magic = 0;
+
+    fd = open("/dev/mem", O_RDONLY);
+    if (fd < 0) {
+        XEN_PT_ERR(NULL, "Can't open /dev/mem: %s\n", strerror(errno));
+        return 0;
+    }
+
+    /*
+     * Check if it a real bios extension.
+     * The magic number is 0xAA55.
+     */
+    if (start != lseek(fd, start, SEEK_SET)) {
+        goto out;
+    }
+    if (read(fd, &magic, 2) != 2) {
+        goto out;
+    }
+    if (magic != 0xAA55) {
+        goto out;
+    }
+
+    /* Find the size of the rom extension */
+    if (start != lseek(fd, start, SEEK_SET)) {
+        goto out;
+    }
+    if (lseek(fd, 2, SEEK_CUR) != (start + 2)) {
+        goto out;
+    }
+    if (read(fd, &bios_size, 1) != 1) {
+        goto out;
+    }
+
+    /* This size is in 512 bytes */
+    bios_size *= 512;
+
+    /*
+     * Set the file to the begining of the rombios,
+     * to start the copy.
+     */
+    if (start != lseek(fd, start, SEEK_SET)) {
+        goto out;
+    }
+
+    if (bios_size != read(fd, buf, bios_size)) {
+        bios_size = 0;
+    }
+
+out:
+    close(fd);
+    return bios_size;
+}
+
+int setup_vga_pt(XenHostPCIDevice *dev)
+{
+    unsigned char *bios = NULL;
+    int bios_size = 0;
+    char *c = NULL;
+    char checksum = 0;
+    int rc = 0;
+
+    if (!gfx_passthru || ((dev->class_code >> 0x8) != 0x0300)) {
+        return rc;
+    }
+
+    bios = malloc(64 * 1024);
+    /* Allocated 64K for the vga bios */
+    if (!bios) {
+        return -1;
+    }
+
+    bios_size = get_vgabios(bios);
+    if (bios_size == 0 || bios_size > 64 * 1024) {
+        XEN_PT_ERR(NULL, "vga bios size (0x%x) is invalid!\n", bios_size);
+        rc = -1;
+        goto out;
+    }
+
+    /* Adjust the bios checksum */
+    for (c = (char *)bios; c < ((char *)bios + bios_size); c++) {
+        checksum += *c;
+    }
+    if (checksum) {
+        bios[bios_size - 1] -= checksum;
+        XEN_PT_LOG(NULL, "vga bios checksum is adjusted!\n");
+    }
+
+    cpu_physical_memory_rw(0xc0000, bios, bios_size, 1);
+out:
+    free(bios);
+    return rc;
+}
diff --git a/qemu-options.hx b/qemu-options.hx
index 56e5fdf..95de002 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1034,6 +1034,15 @@ STEXI
 Rotate graphical output some deg left (only PXA LCD).
 ETEXI
 
+DEF("gfx_passthru", 0, QEMU_OPTION_gfx_passthru,
+    "-gfx_passthru   enable Intel IGD passthrough by XEN\n",
+    QEMU_ARCH_ALL)
+STEXI
+@item -gfx_passthru
+@findex -gfx_passthru
+Enable Intel IGD passthrough by XEN
+ETEXI
+
 DEF("vga", HAS_ARG, QEMU_OPTION_vga,
     "-vga [std|cirrus|vmware|qxl|xenfb|none]\n"
     "                select video card type\n", QEMU_ARCH_ALL)
diff --git a/vl.c b/vl.c
index 316de54..8a91054 100644
--- a/vl.c
+++ b/vl.c
@@ -215,6 +215,9 @@ static bool tcg_allowed = true;
 bool xen_allowed;
 uint32_t xen_domid;
 enum xen_mode xen_mode = XEN_EMULATE;
+#if defined(CONFIG_XEN_PCI_PASSTHROUGH)
+int gfx_passthru = 0;
+#endif
 static int tcg_tb_size;
 
 static int default_serial = 1;
@@ -3775,6 +3778,11 @@ int main(int argc, char **argv, char **envp)
                 }
                 configure_msg(opts);
                 break;
+#if defined(CONFIG_XEN_PCI_PASSTHROUGH)
+            case QEMU_OPTION_gfx_passthru:
+                gfx_passthru = 1;
+                break;
+#endif
             default:
                 os_parse_cmd_args(popt->index, optarg);
             }
-- 
1.7.1