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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [v5][PATCH 1/5] xen, gfx passthrough: basic graphics passthrough support
On Wed, Jun 25, 2014 at 10:17:17AM +0800, Tiejun Chen wrote:
> basic gfx passthrough support:
> - add a vga type for gfx passthrough
> - retrieve VGA bios from sysfs, then load it to guest at 0xC0000
> - register/unregister legacy VGA I/O ports and MMIOs for passthrough GFX
>
> The original patch is from Weidong Han <weidong.han@xxxxxxxxx>
>
> Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
> Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
> Cc: Weidong Han <weidong.han@xxxxxxxxx>
ROM loading code is duplicated from assigned_dev_load_option_rom.
Would it be a problem for you to create a memory region holding
the ROM?
You won't need cpu_physical_memory_rw then, either, or need
the VGA_BIOS_DEFAULT_SIZE hack.
> ---
> v5:
>
> * Just rebase.
>
> v4:
>
> * Fix some typos in the patch head description.
> * Improve some comments.
> * Given that xen_pt_register_vga_regions()/xen_pt_unregister_vga_regions()
> are called unconditionally, so we just return 0 there.
> * Remove one spurious change.
>
> v3:
>
> * Fix some typos.
> * Add more comments to make that readable.
> * Improve some return paths.
>
> v2:
>
> * retrieve VGA bios from sysfs properly.
> * redefine some function name.
>
> 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 | 232
> +++++++++++++++++++++++++++++++++++++++++++
> qemu-options.hx | 9 ++
> vl.c | 10 ++
> 8 files changed, 272 insertions(+), 1 deletion(-)
> create mode 100644 hw/xen/xen_pt_graphics.c
>
> diff --git a/hw/xen/Makefile.objs b/hw/xen/Makefile.objs
> index a0ca0aa..77b7dae 100644
> --- a/hw/xen/Makefile.objs
> +++ b/hw/xen/Makefile.objs
> @@ -2,4 +2,4 @@
> 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
> 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..dac4238 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);
> }
>
> + xen_pt_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);
> }
> +
> + xen_pt_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 passthrough GFX */
> + if (xen_pt_setup_vga(&s->real_device) < 0) {
> + XEN_PT_ERR(d, "Setup VGA BIOS of passthrough 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..4d3a18d 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 xen_has_gfx_passthru;
> +int xen_pt_register_vga_regions(XenHostPCIDevice *dev);
> +int xen_pt_unregister_vga_regions(XenHostPCIDevice *dev);
> +int xen_pt_setup_vga(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..461e526
> --- /dev/null
> +++ b/hw/xen/xen_pt_graphics.c
> @@ -0,0 +1,232 @@
> +/*
> + * graphics passthrough
> + */
> +#include "xen_pt.h"
> +#include "xen-host-pci-device.h"
> +#include "hw/xen/xen_backend.h"
> +
> +static int is_vga_passthrough(XenHostPCIDevice *dev)
> +{
> + return (xen_has_gfx_passthru
> + && ((dev->class_code >> 0x8) == PCI_CLASS_DISPLAY_VGA));
> +}
> +
> +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_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_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;
> +}
> +
> +static int get_vgabios(unsigned char *buf, XenHostPCIDevice *dev)
> +{
> + char rom_file[64];
> + FILE *fp;
> + uint8_t val;
> + struct stat st;
> + uint16_t magic = 0;
> + int ret = 0;
> +
> + snprintf(rom_file, sizeof(rom_file),
> + "/sys/bus/pci/devices/%04x:%02x:%02x.%d/rom",
> + dev->domain, dev->bus, dev->dev,
> + dev->func);
> +
> + if (stat(rom_file, &st)) {
> + return -ENODEV;
> + }
> +
> + if (access(rom_file, F_OK)) {
> + XEN_PT_ERR(NULL, "pci-assign: Insufficient privileges for %s",
> + rom_file);
> + return -ENODEV;
> + }
> +
> + /* Write "1" to the ROM file to enable it */
> + fp = fopen(rom_file, "r+");
> + if (fp == NULL) {
> + return -EACCES;
> + }
> + val = 1;
> + if (fwrite(&val, 1, 1, fp) != 1) {
> + XEN_PT_LOG("%s\n", "Failed to enable pci-sysfs rom file");
> + ret = -EIO;
> + goto close_rom;
> + }
> + fseek(fp, 0, SEEK_SET);
> +
> + /*
> + * Check if it a real bios extension.
> + * The magic number is 0xAA55.
> + */
> + if (!fread(&magic, sizeof(magic), 1, fp)) {
> + XEN_PT_ERR(NULL, "VGA: can't get magic.\n");
> + ret = -ENODEV;
> + goto close_rom;
> + }
> + if (magic != 0xAA55) {
> + XEN_PT_ERR(NULL, "VGA: wrong magic %x.\n", magic);
> + ret = -ENODEV;
> + goto close_rom;
> + }
> + fseek(fp, 0, SEEK_SET);
> +
> + if (!fread(buf, 1, st.st_size, fp)) {
> + XEN_PT_ERR(NULL, "VGA: pci-assign: Cannot read from host %s",
> rom_file);
> + XEN_PT_LOG(NULL, "VGA: Device option ROM contents are probably
> invalid "
> + "(check dmesg).\nSkip option ROM probe with rombar=0, "
> + "or load from file with romfile=\n");
> + }
> +
> +close_rom:
> + /* Write "0" to disable ROM */
> + fseek(fp, 0, SEEK_SET);
> + val = 0;
> + if (!fwrite(&val, 1, 1, fp)) {
> + ret = -EIO;
> + XEN_PT_LOG("%s\n", "Failed to disable pci-sysfs rom file");
> + }
> + fclose(fp);
> + return ret;
> +}
> +
> +/* Allocated 128K for the vga bios */
> +#define VGA_BIOS_DEFAULT_SIZE (0x20000)
> +
> +int xen_pt_setup_vga(XenHostPCIDevice *dev)
> +{
> + unsigned char *bios = NULL;
> + int bios_size = 0;
> + char *c = NULL;
> + char checksum = 0;
> + int rc = 0;
> +
> + if (!is_vga_passthrough(dev)) {
> + return rc;
> + }
> +
> + bios = g_malloc0(VGA_BIOS_DEFAULT_SIZE);
> +
> + bios_size = get_vgabios(bios, dev);
> + if (bios_size) {
> + XEN_PT_ERR(NULL, "VGA: Error %d getting VBIOS!\n", bios_size);
> + if (bios_size < 0) {
> + XEN_PT_ERR(NULL, "VGA: Error (%s).\n", strerror(bios_size));
> + }
> + rc = -1;
> + goto out;
> + }
> +
> + /* Adjust the bios checksum */
It's easy to see that you do this here, but *why* do you do it?
That's what the comment should explain.
Do you see many ROMs with an invalid checksum
in the field?
> + 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");
> + }
> +
> + /* Currently we fixed this address as a primary. */
> + cpu_physical_memory_rw(0xc0000, bios, bios_size, 1);
> +out:
> + g_free(bios);
> + return rc;
> +}
> diff --git a/qemu-options.hx b/qemu-options.hx
> index ff76ad4..1c77baa 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -1066,6 +1066,15 @@ 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|tcx|cg3|none]\n"
> " select video card type\n", QEMU_ARCH_ALL)
> diff --git a/vl.c b/vl.c
> index a1686ef..c5b572d 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1418,6 +1418,13 @@ static void configure_msg(QemuOpts *opts)
> enable_timestamp_msg = qemu_opt_get_bool(opts, "timestamp", true);
> }
>
> +/* We still need this for compatibility with XEN. */
> +int xen_has_gfx_passthru;
> +static void xen_gfx_passthru(const char *optarg)
> +{
> + xen_has_gfx_passthru = 1;
> +}
> +
> /***********************************************************/
> /* USB devices */
>
> @@ -3945,6 +3952,9 @@ int main(int argc, char **argv, char **envp)
> exit(1);
> }
> break;
> + case QEMU_OPTION_gfx_passthru:
> + xen_gfx_passthru(optarg);
> + break;
> default:
> os_parse_cmd_args(popt->index, optarg);
> }
> --
> 1.9.1
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