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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [v2][PATCH 3/8] xen, gfx passthrough: basic graphics passthrough support
On Fri, 16 May 2014, Konrad Rzeszutek Wilk wrote:
> On Fri, May 16, 2014 at 06:53:39PM +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 0xC0000
> > - register/unregister legacy VGA I/O ports and MMIOs for passthroughed 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>
> > ---
> > 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 | 177
> > +++++++++++++++++++++++++++++++++++++++++++
> > qemu-options.hx | 9 +++
> > vl.c | 11 ++-
> > 8 files changed, 217 insertions(+), 2 deletions(-)
> > 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..a0113ea 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 passthroughed gfx */
> > + if (xen_pt_setup_vga(&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..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..e1f0724
> > --- /dev/null
> > +++ b/hw/xen/xen_pt_graphics.c
> > @@ -0,0 +1,177 @@
> > +/*
> > + * 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));
> > +}
> > +
> > +/*
> > + * register VGA resources for the domain with assigned gfx
> > + */
> > +int xen_pt_register_vga_regions(XenHostPCIDevice *dev)
> > +{
> > + int ret = 0;
> > +
> > + if (!is_vga_passthrough(dev)) {
> > + return ret;
> > + }
> > +
> > + ret |= xc_domain_ioport_mapping(xen_xc, xen_domid, 0x3B0,
> > + 0x3B0, 0xA, DPCI_ADD_MAPPING);
The original code does:
ret |= xc_domain_ioport_mapping(xc_handle, domid, 0x3B0,
0x3B0, 0xC, DPCI_ADD_MAPPING);
why are we remapping fewer ports now?
> > + 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) {
> > + XEN_PT_ERR(NULL, "VGA region mapping failed\n");
>
> It would be actually useful to know _which_ of them failed. Perhaps
> you could structure this a bit differently and do:
>
>
> struct _args {
> uint32_t gport;
> uint32_t mport;
> uint32_t nport;
> };
>
> struct _args args[3] = {{ 0x3B0, 0x3B0, 0xA }, {...}};
> unsigned int i;
>
> for (i = 0; i < ARRAY_SIZE(args); i++) {
> ret = xc_domain_ioport_mapping(xen_xc, xen_domid,
> args[i].gport, args[i]..)
> if (ret) {
> XEN_PT_ERR_(NULL, "VGA region mapping of 0x%lx for 0x%x
> pages failed with rc:%d\n",
> ... fill in the values)
> return ret;
> }
>
>
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +/*
> > + * unregister VGA resources for the domain with assigned gfx
> > + */
> > +int xen_pt_unregister_vga_regions(XenHostPCIDevice *dev)
> > +{
> > + int ret = 0;
> > +
> > + if (!is_vga_passthrough(dev)) {
> > + return ret;
> > + }
> > +
> > + ret |= xc_domain_ioport_mapping(xen_xc, xen_domid, 0x3B0,
> > + 0x3B0, 0xC, DPCI_REMOVE_MAPPING);
But here we are unmapping 0xC ioports....
> > + 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) {
> > + XEN_PT_ERR(NULL, "VGA region unmapping failed\n");
> > + }
> > +
>
> The same pattern as above.
>
> > + return ret;
> > +}
> > +
> > +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;
> > +
> > + snprintf(rom_file, sizeof(rom_file),
> > + "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/rom",
>
> I think the format changed to be: /%04x:%02x:%02x.%d in Linux
> (see pci_setup_device in drivers/pci/probe.c) - not that it makes
> that much difference as the function is only up to 7.
>
> > + dev->domain, dev->bus, dev->dev,
> > + dev->func);
> > +
> > + if (stat(rom_file, &st)) {
> > + return -1;
>
> ENODEV?
>
> > + }
> > +
> > + if (access(rom_file, F_OK)) {
> > + XEN_PT_ERR(NULL, "pci-assign: Insufficient privileges for %s",
> > + rom_file);
> > + return -1;
>
> EPERM?
> > + }
> > +
> > + /* Write "1" to the ROM file to enable it */
> > + fp = fopen(rom_file, "r+");
> > + if (fp == NULL) {
>
> EACCESS ?
>
> > + return -1;
> > + }
> > + val = 1;
> > + if (fwrite(&val, 1, 1, fp) != 1) {
> > + 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)) {
> > + goto close_rom;
> > + }
>
> Don't you want to do that before you write '1' in it?
>
> > +
> > + if (magic != 0xAA55) {
> > + goto close_rom;
> > + }
> > + fseek(fp, 0, SEEK_SET);
> > +
> > + if (!fread(buf, 1, st.st_size, fp)) {
> > + XEN_PT_ERR(NULL, "pci-assign: Cannot read from host %s", rom_file);
> > + XEN_PT_LOG(NULL, "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)) {
> > + XEN_PT_LOG("%s\n", "Failed to disable pci-sysfs rom file");
>
> Should we return -1? (after closing the file of course)
>
> > + }
> > + fclose(fp);
> > + return st.st_size;
>
> Ah, that is why your return -1! In that case I presume the caller of this
> function will check the 'errno' to find the underlaying issue
> > +}
> > +
> > +/* Allocated 128K for the vga bios */
> > +#define VGA_BIOS_DEFAULT_SIZE (0x20000)
The old default was 0x10000, why are we changing it?
> > +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 == 0 || bios_size > VGA_BIOS_DEFAULT_SIZE) {
> > + XEN_PT_ERR(NULL, "vga bios size (0x%x) is invalid!\n", bios_size);
>
> Um, with an error code, the 'bios size (0xfffffffff)' is going to show up.
> Why don't you an extra code to check for this , like:
>
> if (bios_size < 0)
> XEN_PT_ERR(NULL,"Error %d (%s) getting BIOS!\n", errno,
> strerror(errno));
> else
> .. the other error.
>
> > + 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");
> > + }
> > +
> > + /* 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 781af14..cece134 100644
> > --- a/qemu-options.hx
> > +++ b/qemu-options.hx
> > @@ -1047,6 +1047,15 @@ 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 73e0661..c86e95f 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -1436,6 +1436,13 @@ static void smp_parse(QemuOpts *opts)
> >
> > }
> >
> > +/* 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;
> > +}
> > +
> > static void configure_realtime(QemuOpts *opts)
> > {
> > bool enable_mlock;
> > @@ -2988,7 +2995,6 @@ int main(int argc, char **argv, char **envp)
> > const char *trace_file = NULL;
> > const ram_addr_t default_ram_size = (ram_addr_t)DEFAULT_RAM_SIZE *
> > 1024 * 1024;
> > -
> > atexit(qemu_run_exit_notifiers);
> > error_set_progname(argv[0]);
> > qemu_init_exec_dir(argv[0]);
> > @@ -3956,6 +3962,9 @@ int main(int argc, char **argv, char **envp)
> > }
> > configure_msg(opts);
> > break;
> > + case QEMU_OPTION_gfx_passthru:
> > + xen_gfx_passthru(optarg);
> > + break;
> > default:
> > os_parse_cmd_args(popt->index, optarg);
> > }
> > --
> > 1.9.1
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxx
> > http://lists.xen.org/xen-devel
>
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