[PATCH 1/2] graphics passthrough with VT-d

[PATCH 1/2] graphics passthrough with VT-d

[Han, Weidong]

[-- Attachment #1: Type: text/plain, Size: 410 bytes --]

This patch supports basic gfx passthrough on xen side:
  - retrieves VGA bios from host VGA BIOS address (0xC0000), then load it to guest VGA BIOS address (This is the same with XCI).
  - Enlarge guest MMIO range to contain gfx card's large memory 
  - add a config option 'gfx_passthru' for gfx passthrough

Signed-off-by: Ben Lin <ben.y.lin@intel.com>
Signed-off-by: Weidong Han <weidong.han@intel.com>

[-- Attachment #2: xen-gfx-passthrough.patch --]
[-- Type: application/octet-stream, Size: 12565 bytes --]

diff -r 5d7e7a250267 tools/firmware/hvmloader/config.h
--- a/tools/firmware/hvmloader/config.h	Wed Aug 26 18:28:44 2009 +0800
+++ b/tools/firmware/hvmloader/config.h	Thu Aug 27 16:54:24 2009 +0800
@@ -15,7 +15,7 @@
 #define PCI_ISA_IRQ_MASK    0x0c20U /* ISA IRQs 5,10,11 are PCI connected */
 
 /* MMIO hole: Hardcoded defaults, which can be dynamically expanded. */
-#define PCI_MEM_START       0xf0000000
+#define PCI_MEM_START       0xe0000000
 #define PCI_MEM_END         0xfc000000
 extern unsigned long pci_mem_start, pci_mem_end;
 
diff -r 5d7e7a250267 tools/firmware/hvmloader/hvmloader.c
--- a/tools/firmware/hvmloader/hvmloader.c	Wed Aug 26 18:28:44 2009 +0800
+++ b/tools/firmware/hvmloader/hvmloader.c	Fri Aug 28 14:41:22 2009 +0800
@@ -113,7 +113,7 @@ unsigned long pci_mem_start = PCI_MEM_ST
 unsigned long pci_mem_start = PCI_MEM_START;
 unsigned long pci_mem_end = PCI_MEM_END;
 
-static enum { VGA_none, VGA_std, VGA_cirrus } virtual_vga = VGA_none;
+static enum { VGA_none, VGA_std, VGA_cirrus, VGA_pt } virtual_vga = VGA_none;
 
 static void init_hypercalls(void)
 {
@@ -212,8 +212,10 @@ static void pci_setup(void)
         case 0x0300:
             if ( (vendor_id == 0x1234) && (device_id == 0x1111) )
                 virtual_vga = VGA_std;
-            if ( (vendor_id == 0x1013) && (device_id == 0xb8) )
+            else if ( (vendor_id == 0x1013) && (device_id == 0xb8) )
                 virtual_vga = VGA_cirrus;
+            else
+                virtual_vga = VGA_pt;
             break;
         case 0x0680:
             /* PIIX4 ACPI PM. Special device with special PCI config space. */
@@ -684,6 +686,11 @@ int main(void)
         memcpy((void *)VGABIOS_PHYSICAL_ADDRESS,
                vgabios_stdvga, sizeof(vgabios_stdvga));
         vgabios_sz = round_option_rom(sizeof(vgabios_stdvga));
+        break;
+    case VGA_pt:
+        printf("Loading VGABIOS of passthroughed gfx ...\n");
+        vgabios_sz =
+            round_option_rom((*(uint8_t *)(VGABIOS_PHYSICAL_ADDRESS+2)) * 512);
         break;
     default:
         printf("No emulated VGA adaptor ...\n");
diff -r 5d7e7a250267 tools/libxc/ia64/xc_ia64_hvm_build.c
--- a/tools/libxc/ia64/xc_ia64_hvm_build.c	Wed Aug 26 18:28:44 2009 +0800
+++ b/tools/libxc/ia64/xc_ia64_hvm_build.c	Thu Aug 27 16:54:24 2009 +0800
@@ -1109,7 +1109,9 @@ int xc_hvm_build_target_mem(int xc_handl
                             uint32_t domid,
                             int memsize,
                             int target,
-                            const char *image_name)
+                            const char *image_name,
+                            int gfx_passthru)
+
 {
     /* XXX:PoD isn't supported yet */
     return xc_hvm_build(xc_handle, domid, target, image_name);
diff -r 5d7e7a250267 tools/libxc/xc_hvm_build.c
--- a/tools/libxc/xc_hvm_build.c	Wed Aug 26 18:28:44 2009 +0800
+++ b/tools/libxc/xc_hvm_build.c	Thu Aug 27 16:54:24 2009 +0800
@@ -64,6 +64,67 @@ static void build_hvm_info(void *hvm_inf
     for ( i = 0, sum = 0; i < hvm_info->length; i++ )
         sum += ((uint8_t *)hvm_info)[i];
     hvm_info->checksum = -sum;
+}
+
+static int init_vgabios(int xc_handle, uint32_t dom,
+                        unsigned char *buffer, uint32_t bios_size)
+{
+    char *va_bios = NULL;
+    uint32_t va_size = 0;
+
+    va_size = bios_size + bios_size % XC_PAGE_SIZE;
+    va_bios = xc_map_foreign_range(xc_handle, dom, va_size,
+                                   PROT_READ | PROT_WRITE, 0xC0);
+    if ( !va_bios )
+    {
+        IPRINTF("Unable to map vga bios!\n");
+        return -1;
+    }
+
+    if ( buffer != NULL )
+        memcpy(va_bios, buffer, bios_size);
+    else
+        memset(va_bios, 0, bios_size);
+
+    munmap(va_bios, va_size);
+    return 0;
+}
+
+static int setup_vga_pt(int xc_handle, uint32_t dom)
+{
+    int                 rc = 0;
+    unsigned char       *bios = NULL;
+    int                 bios_size = 0;
+    char                *c = NULL;
+    char                checksum = 0;
+
+    /* Allocated 64K for the vga bios */
+    if (!(bios = malloc(64 * 1024)))
+        return -1;
+
+#ifdef __linux__
+    bios_size = xc_get_vgabios(bios, 64 * 1024);
+#else
+    bios_size = 0;
+#endif /* __linux__ */
+
+    if (bios_size == 0)
+    {
+        IPRINTF("vga bios size is 0!\n");
+        rc = -1;
+        goto error;
+    }
+
+    /* Adjust the bios checksum */
+    for ( c = (char*)bios; c < ((char*)bios + bios_size); c++ )
+        checksum += *c;
+    if (checksum)
+        bios[bios_size - 1] -= checksum;
+
+    init_vgabios(xc_handle, dom, bios, bios_size);
+error:
+    free(bios);
+    return rc;
 }
 
 static int loadelfimage(
@@ -381,7 +442,8 @@ int xc_hvm_build_target_mem(int xc_handl
                            uint32_t domid,
                            int memsize,
                            int target,
-                           const char *image_name)
+                           const char *image_name,
+                           int gfx_passthru)
 {
     char *image;
     int  sts;
@@ -392,6 +454,11 @@ int xc_hvm_build_target_mem(int xc_handl
         return -1;
 
     sts = xc_hvm_build_internal(xc_handle, domid, memsize, target, image, image_size);
+
+    if ( gfx_passthru )
+        sts |= setup_vga_pt(xc_handle, domid);
+    else
+        sts |= init_vgabios(xc_handle, domid, NULL, 0x800);
 
     free(image);
 
diff -r 5d7e7a250267 tools/libxc/xc_linux.c
--- a/tools/libxc/xc_linux.c	Wed Aug 26 18:28:44 2009 +0800
+++ b/tools/libxc/xc_linux.c	Thu Aug 27 16:54:24 2009 +0800
@@ -638,6 +638,56 @@ err:
     return gnt;
 }
 
+int xc_get_vgabios(unsigned char        *buf,
+                   int                  len)
+{
+    int         mem;
+    uint32_t    start, size = 0;
+    uint16_t    magic = 0;
+
+    start = 0xC0000;
+    if (len < size)
+        return 0;
+    if ((mem = open("/dev/mem", O_RDONLY)) < 0)
+        return 0;
+
+    /*
+    ** Check if it a real bios extension.
+    ** The magic number is 0xAA55.
+    */
+    if (start != lseek(mem, start, SEEK_SET))
+        goto out;
+    if (read(mem, &magic, 2) != 2)
+        goto out;
+    if (magic != 0xAA55)
+        goto out;
+    /* Find the size of the rom extension */
+    if (start != lseek(mem, start, SEEK_SET))
+        goto out;
+    if (lseek(mem, 2, SEEK_CUR) != (start + 2))
+        goto out;
+    if (read(mem, &size, 1) != 1)
+        goto out;
+    /* This size is in 512K */
+    size *= 512;
+
+    /*
+    ** Set the file to the begining of the rombios,
+    ** to start the copy.
+    */
+    if (start != lseek(mem, start, SEEK_SET))
+    {
+        size = 0;
+        goto out;
+    }
+    if (size != read(mem, buf, size))
+        size = 0;
+
+out:
+    close(mem);
+    return size;
+}
+
 /*
  * Local variables:
  * mode: C
diff -r 5d7e7a250267 tools/libxc/xenctrl.h
--- a/tools/libxc/xenctrl.h	Wed Aug 26 18:28:44 2009 +0800
+++ b/tools/libxc/xenctrl.h	Thu Aug 27 16:54:24 2009 +0800
@@ -1285,4 +1285,6 @@ int xc_tmem_restore(int xc_handle, int d
 int xc_tmem_restore(int xc_handle, int dom, int fd);
 int xc_tmem_restore_extra(int xc_handle, int dom, int fd);
 
+int xc_get_vgabios(unsigned char *bios, int len);
+
 #endif /* XENCTRL_H */
diff -r 5d7e7a250267 tools/libxc/xenguest.h
--- a/tools/libxc/xenguest.h	Wed Aug 26 18:28:44 2009 +0800
+++ b/tools/libxc/xenguest.h	Thu Aug 27 16:54:24 2009 +0800
@@ -135,7 +135,8 @@ int xc_hvm_build_target_mem(int xc_handl
                             uint32_t domid,
                             int memsize,
                             int target,
-                            const char *image_name);
+                            const char *image_name,
+                            int gfx_passthru);
 
 int xc_hvm_build_mem(int xc_handle,
                      uint32_t domid,
diff -r 5d7e7a250267 tools/python/xen/lowlevel/xc/xc.c
--- a/tools/python/xen/lowlevel/xc/xc.c	Wed Aug 26 18:28:44 2009 +0800
+++ b/tools/python/xen/lowlevel/xc/xc.c	Thu Aug 27 16:54:24 2009 +0800
@@ -894,21 +894,21 @@ static PyObject *pyxc_hvm_build(XcObject
     int i;
 #endif
     char *image;
-    int memsize, target=-1, vcpus = 1, acpi = 0, apic = 1;
+    int memsize, target=-1, vcpus = 1, acpi = 0, apic = 1, gfx_passthru = 0;
 
     static char *kwd_list[] = { "domid",
                                 "memsize", "image", "target", "vcpus", "acpi",
-                                "apic", NULL };
-    if ( !PyArg_ParseTupleAndKeywords(args, kwds, "iis|iiii", kwd_list,
+                                "apic", "gfx_passthru", NULL };
+    if ( !PyArg_ParseTupleAndKeywords(args, kwds, "iis|iiiii", kwd_list,
                                       &dom, &memsize, &image, &target, &vcpus,
-                                      &acpi, &apic) )
+                                      &acpi, &apic, &gfx_passthru) )
         return NULL;
 
     if ( target == -1 )
         target = memsize;
 
     if ( xc_hvm_build_target_mem(self->xc_handle, dom, memsize,
-                                 target, image) != 0 )
+                                 target, image, gfx_passthru) != 0 )
         return pyxc_error_to_exception();
 
 #if !defined(__ia64__)
diff -r 5d7e7a250267 tools/python/xen/xend/XendConfig.py
--- a/tools/python/xen/xend/XendConfig.py	Wed Aug 26 18:28:44 2009 +0800
+++ b/tools/python/xen/xend/XendConfig.py	Thu Aug 27 16:54:24 2009 +0800
@@ -175,6 +175,7 @@ XENAPI_PLATFORM_CFG_TYPES = {
     'pci_msitranslate': int,
     'pci_power_mgmt': int,
     'xen_platform_pci': int,
+    "gfx_passthru": int,
 }
 
 # Xen API console 'other_config' keys.
diff -r 5d7e7a250267 tools/python/xen/xend/image.py
--- a/tools/python/xen/xend/image.py	Wed Aug 26 18:28:44 2009 +0800
+++ b/tools/python/xen/xend/image.py	Thu Aug 27 16:54:24 2009 +0800
@@ -786,7 +786,7 @@ class HVMImageHandler(ImageHandler):
         self.apic = int(vmConfig['platform'].get('apic', 0))
         self.acpi = int(vmConfig['platform'].get('acpi', 0))
         self.guest_os_type = vmConfig['platform'].get('guest_os_type')
-
+        self.gfx_passthru = int(vmConfig['platform'].get('gfx_passthru', 0))
 
     # Return a list of cmd line args to the device models based on the
     # xm config file
@@ -807,7 +807,7 @@ class HVMImageHandler(ImageHandler):
 
         dmargs = [ 'boot', 'fda', 'fdb', 'soundhw',
                    'localtime', 'serial', 'stdvga', 'isa',
-                   'acpi', 'usb', 'usbdevice' ]
+                   'acpi', 'usb', 'usbdevice', 'gfx_passthru' ]
 
         for a in dmargs:
             v = vmConfig['platform'].get(a)
@@ -901,6 +901,7 @@ class HVMImageHandler(ImageHandler):
         log.debug("vcpus          = %d", self.vm.getVCpuCount())
         log.debug("acpi           = %d", self.acpi)
         log.debug("apic           = %d", self.apic)
+        log.debug("gfx_passthru   = %d", self.gfx_passthru)
 
         rc = xc.hvm_build(domid          = self.vm.getDomid(),
                           image          = self.loader,
@@ -908,7 +909,8 @@ class HVMImageHandler(ImageHandler):
                           target         = mem_mb,
                           vcpus          = self.vm.getVCpuCount(),
                           acpi           = self.acpi,
-                          apic           = self.apic)
+                          apic           = self.apic,
+                          gfx_passthru   = self.gfx_passthru)
         rc['notes'] = { 'SUSPEND_CANCEL': 1 }
 
         rc['store_mfn'] = xc.hvm_get_param(self.vm.getDomid(),
diff -r 5d7e7a250267 tools/python/xen/xm/create.py
--- a/tools/python/xen/xm/create.py	Wed Aug 26 18:28:44 2009 +0800
+++ b/tools/python/xen/xm/create.py	Thu Aug 27 16:54:24 2009 +0800
@@ -546,6 +546,10 @@ gopts.var('sdl', val='',
 gopts.var('sdl', val='',
           fn=set_value, default=None,
           use="""Should the device model use SDL?""")
+
+gopts.var('gfx_passthru', val='',
+          fn=set_value, default=None,
+          use="""Passthrough graphics card?""")
 
 gopts.var('opengl', val='',
           fn=set_value, default=None,
@@ -957,7 +961,8 @@ def configure_hvm(config_image, vals):
              'acpi', 'apic', 'usb', 'usbdevice', 'keymap', 'pci', 'hpet',
              'guest_os_type', 'hap', 'opengl', 'cpuid', 'cpuid_check',
              'viridian', 'xen_extended_power_mgmt', 'pci_msitranslate',
-             'vpt_align', 'pci_power_mgmt', 'xen_platform_pci' ]
+             'vpt_align', 'pci_power_mgmt', 'xen_platform_pci',
+             'gfx_passthru' ]
 
     for a in args:
         if a in vals.__dict__ and vals.__dict__[a] is not None:

[-- Attachment #3: Type: text/plain, Size: 138 bytes --]

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Re: [PATCH 1/2] graphics passthrough with VT-d

[Jean Guyader]

On Fri, Aug 28, 2009 at 03:54:05AM -0400, Han, Weidong wrote:
> This patch supports basic gfx passthrough on xen side:
>   - retrieves VGA bios from host VGA BIOS address (0xC0000), then load it to guest VGA BIOS address (This is the same with XCI).
>   - Enlarge guest MMIO range to contain gfx card's large memory 
>   - add a config option 'gfx_passthru' for gfx passthrough
> 
> Signed-off-by: Ben Lin <ben.y.lin@intel.com>
> Signed-off-by: Weidong Han <weidong.han@intel.com>

Hi,

First thanks for taking the time to upstream those patch
that will help a lot.

I think the patch will be let intrusive if we could do all
that bios mapping + copying inside qemu so we don't need to
modify the xc_hvm_build function.

Qemu starts before the bios so that should be doable.

Thanks,
Jean

RE: [PATCH 1/2] graphics passthrough with VT-d

[Han, Weidong]

Jean Guyader wrote:
> On Fri, Aug 28, 2009 at 03:54:05AM -0400, Han, Weidong wrote:
>> This patch supports basic gfx passthrough on xen side:
>>   - retrieves VGA bios from host VGA BIOS address (0xC0000), then
>> load it to guest VGA BIOS address (This is the same with XCI). 
>>   - Enlarge guest MMIO range to contain gfx card's large memory
>>   - add a config option 'gfx_passthru' for gfx passthrough
>> 
>> Signed-off-by: Ben Lin <ben.y.lin@intel.com>
>> Signed-off-by: Weidong Han <weidong.han@intel.com>
> 
> Hi,
> 
> First thanks for taking the time to upstream those patch
> that will help a lot.
> 
> I think the patch will be let intrusive if we could do all
> that bios mapping + copying inside qemu so we don't need to
> modify the xc_hvm_build function.
> 
> Qemu starts before the bios so that should be doable.
> 
> Thanks,
> Jean

Sounds good. 

You mean mapping + coping vgabios in hw/pc.c, right? We will go to change it. Thanks.

Regards,
Weidong

Re: [PATCH 1/2] graphics passthrough with VT-d

[Keir Fraser]

On 28/08/2009 08:54, "Han, Weidong" <weidong.han@intel.com> wrote:

> This patch supports basic gfx passthrough on xen side:
>   - retrieves VGA bios from host VGA BIOS address (0xC0000), then load it to
> guest VGA BIOS address (This is the same with XCI).
>   - Enlarge guest MMIO range to contain gfx card's large memory

Hvmloader will auto-size the MMIO hole. You shouldn't need to change the
default initial size of the hole.

 -- Keir

>   - add a config option 'gfx_passthru' for gfx passthrough

RE: [PATCH 1/2] graphics passthrough with VT-d

[Han, Weidong]

Keir Fraser wrote:
> On 28/08/2009 08:54, "Han, Weidong" <weidong.han@intel.com> wrote:
> 
>> This patch supports basic gfx passthrough on xen side:
>>   - retrieves VGA bios from host VGA BIOS address (0xC0000), then
>> load it to guest VGA BIOS address (This is the same with XCI).
>>   - Enlarge guest MMIO range to contain gfx card's large memory
> 
> Hvmloader will auto-size the MMIO hole. You shouldn't need to change
> the default initial size of the hole.

Ok. I will remove the change. Thanks.

Regards,
Weidong

> 
>  -- Keir
> 
>>   - add a config option 'gfx_passthru' for gfx passthrough

Re: [PATCH 1/2] graphics passthrough with VT-d

[Stefano Stabellini]

On Fri, 28 Aug 2009, Jean Guyader wrote:
> On Fri, Aug 28, 2009 at 03:54:05AM -0400, Han, Weidong wrote:
> > This patch supports basic gfx passthrough on xen side:
> >   - retrieves VGA bios from host VGA BIOS address (0xC0000), then load it to guest VGA BIOS address (This is the same with XCI).
> >   - Enlarge guest MMIO range to contain gfx card's large memory 
> >   - add a config option 'gfx_passthru' for gfx passthrough
> > 
> > Signed-off-by: Ben Lin <ben.y.lin@intel.com>
> > Signed-off-by: Weidong Han <weidong.han@intel.com>
> 
> Hi,
> 
> First thanks for taking the time to upstream those patch
> that will help a lot.
> 
> I think the patch will be let intrusive if we could do all
> that bios mapping + copying inside qemu so we don't need to
> modify the xc_hvm_build function.
> 
> Qemu starts before the bios so that should be doable.

The problem with letting qemu do the mapping is that it is not going to
work with stubdoms, while using a libxc function should work OK as long
as it is called by xend, as in this case.

RE: [PATCH 1/2] graphics passthrough with VT-d

[Han, Weidong]

Stefano Stabellini wrote:
> On Fri, 28 Aug 2009, Jean Guyader wrote:
>> On Fri, Aug 28, 2009 at 03:54:05AM -0400, Han, Weidong wrote:
>>> This patch supports basic gfx passthrough on xen side:
>>>   - retrieves VGA bios from host VGA BIOS address (0xC0000), then
>>> load it to guest VGA BIOS address (This is the same with XCI). 
>>>   - Enlarge guest MMIO range to contain gfx card's large memory
>>>   - add a config option 'gfx_passthru' for gfx passthrough
>>> 
>>> Signed-off-by: Ben Lin <ben.y.lin@intel.com>
>>> Signed-off-by: Weidong Han <weidong.han@intel.com>
>> 
>> Hi,
>> 
>> First thanks for taking the time to upstream those patch that will
>> help a lot. 
>> 
>> I think the patch will be let intrusive if we could do all
>> that bios mapping + copying inside qemu so we don't need to
>> modify the xc_hvm_build function.
>> 
>> Qemu starts before the bios so that should be doable.
> 
> The problem with letting qemu do the mapping is that it is not going
> to work with stubdoms, while using a libxc function should work OK as
> long as it is called by xend, as in this case.

Currently stubdom doesn't support VT-d. So letting qemu do the mapping is much cleaner.

Regards,
Weidong

Re: [PATCH 1/2] graphics passthrough with VT-d

[Jean Guyader]

2009/9/16 Han, Weidong <weidong.han@intel.com>:
> Stefano Stabellini wrote:
>> On Fri, 28 Aug 2009, Jean Guyader wrote:
>>> On Fri, Aug 28, 2009 at 03:54:05AM -0400, Han, Weidong wrote:
>>>> This patch supports basic gfx passthrough on xen side:
>>>>   - retrieves VGA bios from host VGA BIOS address (0xC0000), then
>>>> load it to guest VGA BIOS address (This is the same with XCI).
>>>>   - Enlarge guest MMIO range to contain gfx card's large memory
>>>>   - add a config option 'gfx_passthru' for gfx passthrough
>>>>
>>>> Signed-off-by: Ben Lin <ben.y.lin@intel.com>
>>>> Signed-off-by: Weidong Han <weidong.han@intel.com>
>>>
>>> Hi,
>>>
>>> First thanks for taking the time to upstream those patch that will
>>> help a lot.
>>>
>>> I think the patch will be let intrusive if we could do all
>>> that bios mapping + copying inside qemu so we don't need to
>>> modify the xc_hvm_build function.
>>>
>>> Qemu starts before the bios so that should be doable.
>>
>> The problem with letting qemu do the mapping is that it is not going
>> to work with stubdoms, while using a libxc function should work OK as
>> long as it is called by xend, as in this case.
>
> Currently stubdom doesn't support VT-d. So letting qemu do the mapping is much cleaner.
>

I remember I tried graphic pass through a while ago with stubdom and
it did work.

Jean

RE: [PATCH 1/2] graphics passthrough with VT-d

[Han, Weidong]

Jean Guyader wrote:
> 2009/9/16 Han, Weidong <weidong.han@intel.com>:
>> Stefano Stabellini wrote:
>>> On Fri, 28 Aug 2009, Jean Guyader wrote:
>>>> On Fri, Aug 28, 2009 at 03:54:05AM -0400, Han, Weidong wrote:
>>>>> This patch supports basic gfx passthrough on xen side:
>>>>>   - retrieves VGA bios from host VGA BIOS address (0xC0000), then
>>>>> load it to guest VGA BIOS address (This is the same with XCI).
>>>>>   - Enlarge guest MMIO range to contain gfx card's large memory
>>>>>   - add a config option 'gfx_passthru' for gfx passthrough
>>>>> 
>>>>> Signed-off-by: Ben Lin <ben.y.lin@intel.com>
>>>>> Signed-off-by: Weidong Han <weidong.han@intel.com>
>>>> 
>>>> Hi,
>>>> 
>>>> First thanks for taking the time to upstream those patch that will
>>>> help a lot. 
>>>> 
>>>> I think the patch will be let intrusive if we could do all
>>>> that bios mapping + copying inside qemu so we don't need to
>>>> modify the xc_hvm_build function.
>>>> 
>>>> Qemu starts before the bios so that should be doable.
>>> 
>>> The problem with letting qemu do the mapping is that it is not going
>>> to work with stubdoms, while using a libxc function should work OK
>>> as long as it is called by xend, as in this case.
>> 
>> Currently stubdom doesn't support VT-d. So letting qemu do the
>> mapping is much cleaner. 
>> 
> 
> I remember I tried graphic pass through a while ago with stubdom and
> it did work.
> 

I heard VT-d didn't work with stubdom, it needs some efforts to support it. Actually I didn't try stubdom with VT-d. 

Regards,
Weidong

RE: [PATCH 1/2] graphics passthrough with VT-d

[Stefano Stabellini]

On Wed, 16 Sep 2009, Han, Weidong wrote:
> I heard VT-d didn't work with stubdom, it needs some efforts to support it. Actually I didn't try stubdom with VT-d. 
> 

You are right, currently stubdom doesn't work with passthrough.
I have a patch series to make it work but it is not finished yet and I
have been pulled on other projects; I hope to resume my work on that in
the near future.

In any case the fact the currently passthrough doesn't work with
stubdom is not a good reason for introducing even more problematic
changes.

RE: [PATCH 1/2] graphics passthrough with VT-d

[Han, Weidong]

Stefano Stabellini wrote:
> On Wed, 16 Sep 2009, Han, Weidong wrote:
>> I heard VT-d didn't work with stubdom, it needs some efforts to
>> support it. Actually I didn't try stubdom with VT-d. 
>> 
> 
> You are right, currently stubdom doesn't work with passthrough.
> I have a patch series to make it work but it is not finished yet and I
> have been pulled on other projects; I hope to resume my work on that
> in the near future.
> 
> In any case the fact the currently passthrough doesn't work with
> stubdom is not a good reason for introducing even more problematic
> changes.

Actually stubdom is missed when changing the patch. It is easy to change. We will change it.

Regards,
Weidong

RE: [PATCH 1/2] graphics passthrough with VT-d

[Han, Weidong]

Stefano Stabellini wrote:
> On Wed, 16 Sep 2009, Han, Weidong wrote:
>> I heard VT-d didn't work with stubdom, it needs some efforts to
>> support it. Actually I didn't try stubdom with VT-d. 
>> 
> 
> You are right, currently stubdom doesn't work with passthrough.
> I have a patch series to make it work but it is not finished yet and I
> have been pulled on other projects; I hope to resume my work on that
> in the near future.
> 
> In any case the fact the currently passthrough doesn't work with
> stubdom is not a good reason for introducing even more problematic
> changes.

There are many changes on qemu for gfx passthrough, copying and mapping vbios in qemu just a small part. If other changes on qemu can be implemented correspondingly in stubdom, why not copying and mapping vbios in qemu?

Regards,
Weidong

RE: [PATCH 1/2] graphics passthrough with VT-d

[Stefano Stabellini]

On Fri, 18 Sep 2009, Han, Weidong wrote:
> Stefano Stabellini wrote:
> > On Wed, 16 Sep 2009, Han, Weidong wrote:
> >> I heard VT-d didn't work with stubdom, it needs some efforts to
> >> support it. Actually I didn't try stubdom with VT-d. 
> >> 
> > 
> > You are right, currently stubdom doesn't work with passthrough.
> > I have a patch series to make it work but it is not finished yet and I
> > have been pulled on other projects; I hope to resume my work on that
> > in the near future.
> > 
> > In any case the fact the currently passthrough doesn't work with
> > stubdom is not a good reason for introducing even more problematic
> > changes.
> 
> There are many changes on qemu for gfx passthrough, copying and mapping vbios in qemu just a small part. If other changes on qemu can be implemented correspondingly in stubdom, why not copying and mapping vbios in qemu?
> 

Because it would require the stubdom to be able to read the vgabios and
it would be better if we avoid it.

RE: [PATCH 1/2] graphics passthrough with VT-d

[Han, Weidong]

Stefano Stabellini wrote:
> On Fri, 18 Sep 2009, Han, Weidong wrote:
>> Stefano Stabellini wrote:
>>> On Wed, 16 Sep 2009, Han, Weidong wrote:
>>>> I heard VT-d didn't work with stubdom, it needs some efforts to
>>>> support it. Actually I didn't try stubdom with VT-d.
>>>> 
>>> 
>>> You are right, currently stubdom doesn't work with passthrough.
>>> I have a patch series to make it work but it is not finished yet
>>> and I have been pulled on other projects; I hope to resume my work
>>> on that in the near future. 
>>> 
>>> In any case the fact the currently passthrough doesn't work with
>>> stubdom is not a good reason for introducing even more problematic
>>> changes.
>> 
>> There are many changes on qemu for gfx passthrough, copying and
>> mapping vbios in qemu just a small part. If other changes on qemu
>> can be implemented correspondingly in stubdom, why not copying and
>> mapping vbios in qemu?   
>> 
> 
> Because it would require the stubdom to be able to read the vgabios
> and it would be better if we avoid it.

The problem of changing on xc_hvm_build is need to modify hypercall API (xc_hvm_build_target_mem), it's better to avoid it. If it is more intrusive or harder to read vgabios in stubdom, we can change it back to modify xc_hvm_build.

Regards,
Weidong

RE: [PATCH 1/2] graphics passthrough with VT-d

[Stefano Stabellini]

On Sun, 20 Sep 2009, Han, Weidong wrote:
> The problem of changing on xc_hvm_build is need to modify hypercall API (xc_hvm_build_target_mem), it's better to avoid it. If it is more intrusive or harder to read vgabios in stubdom, we can change it back to modify xc_hvm_build.
> 

You could leave xc_hvm_build_target_mem as it is and implement
something similar to:

+    if ( gfx_passthru )
+        sts |= setup_vga_pt(xc_handle, domid);
+    else
+        sts |= init_vgabios(xc_handle, domid, NULL, 0x800);

in pyxc_hvm_build instead so that there is no need for API changes and
the vga bios would still be read from a process in dom0 (xend in this 
case).