Re: [Qemu-devel] [v2][PATCH 2/2] libxl: introduce gfx_passthru_kind

["Chen, Tiejun" <tiejun.chen@intel.com>]

>> +
>> +        if (b_info->u.hvm.gfx_passthru_kind ==
>> +                LIBXL_GFX_PASSTHRU_KIND_DEFAULT) {
>> +            if (libxl__is_igd_vga_passthru(gc, guest_config))
>> +                machinearg = GCSPRINTF("%s,igd-passthru=on", machinearg);
>> +        } else if (b_info->u.hvm.gfx_passthru_kind ==
>> +                        LIBXL_GFX_PASSTHRU_KIND_IGD) {
>> +                machinearg = GCSPRINTF("%s,igd-passthru=on", machinearg);
>> +        } else {
>> +            LOG(WARN, "gfx_passthru_kind is invalid so ignored.\n");
>> +        }
>
> I think this whole block should be inside an:
>          if (libxl_defbool_val(b_info->u.hvm.gfx_passthru)
> the semantics should be that kind is ignored unless passthru is enabled.
>
> and then the if/else chain could become a switch perhaps?

Okay.

>
> I'm unsure what we should do if kind==DEFAULT but
> libxl__is_igd_vga_passthru fails. At a minimum a warning seems
> desirable. I'm not sure if it should warrant a failure or not.

I think a warning message plus abort() should be enough, and then user 
can determine what's next,

Please take a look at this,

+
+        if (libxl_defbool_val(b_info->u.hvm.gfx_passthru)) {
+            switch (b_info->u.hvm.gfx_passthru_kind) {
+            case LIBXL_GFX_PASSTHRU_KIND_DEFAULT:
+                if (libxl__is_igd_vga_passthru(gc, guest_config)) {
+                    machinearg = GCSPRINTF("%s,igd-passthru=on", 
machinearg);
+                } else {
+                    LOG(WARN, "No supported IGD to passthru,"
+                        " or please force set gfx_passthru=\"igd\".\n");
+                    abort();
+                }
+                break;
+            case LIBXL_GFX_PASSTHRU_KIND_IGD:
+                machinearg = GCSPRINTF("%s,igd-passthru=on", machinearg);
+                break;
+            default:
+                LOG(WARN, "gfx_passthru_kind is invalid so ignored.\n");
+                break;
+            }
+        }
+

>
>> +
>>           flexarray_append(dm_args, machinearg);
>>           for (i = 0; b_info->extra_hvm && b_info->extra_hvm[i] != NULL; i++)
>>               flexarray_append(dm_args, b_info->extra_hvm[i]);
>> diff --git a/tools/libxl/libxl_pci.c b/tools/libxl/libxl_pci.c
>> index fc060c6..9a534cc 100644
>> --- a/tools/libxl/libxl_pci.c
>> +++ b/tools/libxl/libxl_pci.c
>> @@ -608,11 +608,11 @@ bool libxl__is_igd_vga_passthru(libxl__gc *gc,
>>               device = fixup_ids[j].device;
>>
>>               if (pt_vendor == vendor &&  pt_device == device)
>> -                return 1;
>> +                return true;
>>           }
>>       }
>>
>> -    return 0;
>> +    return false;
>
> Please fold this into the previous patch. (You may retain the ack I
> gave).

Thanks for your catch.

>>   }
>>
>>   /*
>> diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
>> index 02be466..d64ad10 100644
>> --- a/tools/libxl/libxl_types.idl
>> +++ b/tools/libxl/libxl_types.idl
>> @@ -140,6 +140,11 @@ libxl_tsc_mode = Enumeration("tsc_mode", [
>>       (3, "native_paravirt"),
>>       ])
>>
>> +libxl_gfx_passthru_kind = Enumeration("gfx_passthru_kind", [
>> +    (0, "default"),
>> +    (1, "igd"),
>> +    ])
>> +
>>   # Consistent with the values defined for HVM_PARAM_TIMER_MODE.
>>   libxl_timer_mode = Enumeration("timer_mode", [
>>       (-1, "unknown"),
>> @@ -430,6 +435,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
>>                                          ("spice",            libxl_spice_info),
>>
>>                                          ("gfx_passthru",     libxl_defbool),
>> +                                       ("gfx_passthru_kind", libxl_gfx_passthru_kind),
>
> Please add a #define LIBXL_HAVE_... to libxl.h to indicate that this
> functionality is now available. There is a comment near the top
> explaining why etc and a bunch of examples.
>
> Note that the #define is for 3rd party code only, there is no need to
> actually use it in either libxl or xl code.

Like this,

@@ -720,6 +720,13 @@ void libxl_mac_copy(libxl_ctx *ctx, libxl_mac *dst, 
libxl_mac *src);
  #define LIBXL_HAVE_PSR_MBM 1
  #endif

+/*
+ * LIBXL_HAVE_GFX_PASSTHRU_KIND
+ *
+ * If this is defined, the Graphic Device Passthrough Override is 
supported.
+ */
+#define LIBXL_HAVE_GFX_PASSTHRU_KIND 1
+
  typedef char **libxl_string_list;
  void libxl_string_list_dispose(libxl_string_list *sl);
  int libxl_string_list_length(const libxl_string_list *sl);
@@ -1501,6 +1508,11 @@ int libxl_psr_cmt_get_sample(libxl_ctx *ctx,
                               uint64_t *tsc_r);
  #endif

+#ifdef LIBXL_HAVE_GFX_PASSTHRU_KIND
+bool libxl__is_igd_vga_passthru(libxl__gc *gc,
+                                const libxl_domain_config *d_config);
+#endif
+
  /* misc */

  /* Each of these sets or clears the flag according to whether the

But looks libxl__gc{} is defined in the libxl_internal.h file... I guess 
we need a conversion, or other idea?

>
>>                                          ("serial",           string),
>>                                          ("boot",             string),
>> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
>> index 440db78..d0d6ce3 100644
>> --- a/tools/libxl/xl_cmdimpl.c
>> +++ b/tools/libxl/xl_cmdimpl.c
>> @@ -1953,8 +1953,26 @@ skip_vfb:
>>           xlu_cfg_replace_string (config, "spice_streaming_video",
>>                                   &b_info->u.hvm.spice.streaming_video, 0);
>>           xlu_cfg_get_defbool(config, "nographic", &b_info->u.hvm.nographic, 0);
>> -        xlu_cfg_get_defbool(config, "gfx_passthru",
>> -                            &b_info->u.hvm.gfx_passthru, 0);
>> +        if (!xlu_cfg_get_long(config, "gfx_passthru", &l, 1)) {
>> +            if (!l) {
>> +                libxl_defbool_set(&b_info->u.hvm.gfx_passthru, false);
>> +            } else if (i == 1) {
>> +                libxl_defbool_set(&b_info->u.hvm.gfx_passthru, true);
>> +            } else {
>> +                fprintf(stderr,
>> +                        "ERROR: invalid value %ld for \"gfx_passthru\"\n", l);
>> +                exit (1);
>> +            }
>
> The docs (xl.cfg man page) say, regarding booleans "A C<NUMBER>
> interpreted as C<False> (C<0>) or C<True> (any other value)."
>
> So just libxl_defbool_set(&b_info->u.hvm.gfx_passthru, l); should be
> fine here.
>
>> +        } else if (!xlu_cfg_get_string(config, "gfx_passthru", &buf, 0)) {
>> +            if (libxl_gfx_passthru_kind_from_string(buf,
>> +                                        &b_info->u.hvm.gfx_passthru_kind)) {
>> +                fprintf(stderr,
>> +                        "ERROR: invalid value \"%s\" for \"gfx_passthru\"\n",
>> +                        buf);
>> +                exit (1);
>> +            }
>> +            libxl_defbool_set(&b_info->u.hvm.gfx_passthru, false);
>
> Should be true, I see you wrote false in the commit message so I assume
> this was my mistake from earlier as well, sorry about that.
>

Here I update this chunk of code based on your two comments:

@@ -1953,8 +1953,22 @@ skip_vfb:
          xlu_cfg_replace_string (config, "spice_streaming_video",
                                  &b_info->u.hvm.spice.streaming_video, 0);
          xlu_cfg_get_defbool(config, "nographic", 
&b_info->u.hvm.nographic, 0);
-        xlu_cfg_get_defbool(config, "gfx_passthru",
-                            &b_info->u.hvm.gfx_passthru, 0);
+        if (!xlu_cfg_get_long(config, "gfx_passthru", &l, 1)) {
+            if (l) {
+                libxl_defbool_set(&b_info->u.hvm.gfx_passthru, true);
+            } else {
+                libxl_defbool_set(&b_info->u.hvm.gfx_passthru, false);
+            }
+        } else if (!xlu_cfg_get_string(config, "gfx_passthru", &buf, 0)) {
+            if (libxl_gfx_passthru_kind_from_string(buf,
+ 
&b_info->u.hvm.gfx_passthru_kind)) {
+                fprintf(stderr,
+                        "ERROR: invalid value \"%s\" for 
\"gfx_passthru\"\n",
+                        buf);
+                exit (1);
+            }
+            libxl_defbool_set(&b_info->u.hvm.gfx_passthru, true);
+        }
          switch (xlu_cfg_get_list_as_string_list(config, "serial",
 
&b_info->u.hvm.serial_list,
                                                  1))

Thanks
Tiejun