On 08.05.2020 18:41, Jim Fehlig wrote:
> On 4/30/20 6:07 AM, Artur Puzio wrote:
>> gfx_passthru xl.cfg option enables GPU specific quirks required for
>> working
>> Intel GPU passthru. Qemu (used for device model by xen) will refuse
>> to start
>> a VM when an IGD is passed, but this option was not set in Xen.
>
> Do we really need to expose this setting to the user? I'm not really
> sure what to think about it after reading the xl.cfg(5) man page. It
> starts with
>
> gfx_passthru=BOOLEAN|"STRING"
>
> The setting can be a boolean or a string - nice. And it really seems
> specific to Intel graphics cards. The man page claims that a value of
> 1 "Enables graphics device PCI passthrough and autodetects the type of
> device which is being used.". It also says "Note that some graphics
> cards (AMD/ATI cards, for example) do not necessarily require the
> gfx_passthru option".
>
> Can't libxl just enable this itself if there's a PCI passthrough
> device and it's detected as type igd?
>
> Regards,
> Jim
Hi, sorry for slowish response.
Setting gfx_passthru to 1 as in this patch enables the autodetection
routines (it's equivalent to gfx_passthru=1 from xl.cfg). Currently
libxl handles only IGD. If there is no IGD specified at creation and
gfx_passthru is 1, autodetection routines will report an error
preventing domain creation. Relevant libxl code:
libxl_dm.c:1746
if (libxl_defbool_val(b_info->u.hvm.gfx_passthru)) {
enum libxl_gfx_passthru_kind gfx_passthru_kind =
libxl__detect_gfx_passthru_kind(gc,
guest_config);
switch (gfx_passthru_kind) {
case LIBXL_GFX_PASSTHRU_KIND_IGD:
machinearg = GCSPRINTF("%s,igd-passthru=on", machinearg);
break;
case LIBXL_GFX_PASSTHRU_KIND_DEFAULT:
LOGD(ERROR, guest_domid, "unable to detect required
gfx_passthru_kind");
return ERROR_FAIL;
default:
LOGD(ERROR, guest_domid, "invalid value for
gfx_passthru_kind");
return ERROR_INVAL;
}
}
libxl contains a function for checking if IGD is present. After some
testing I will send another version of this patch that will enable
gfx_passthru if there is a IGD attached.
Artur
>
>>
>> Signed-off-by: Artur Puzio <contact@xxxxxxxxxxxx>
>> ---
>> docs/formatdomain.html.in | 7 +++++++
>> docs/schemas/domaincommon.rng | 5 +++++
>> src/conf/domain_conf.c | 4 ++++
>> src/conf/domain_conf.h | 1 +
>> src/libxl/libxl_conf.c | 13 +++++++++++++
>> 5 files changed, 30 insertions(+)
>>
>> diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
>> index 91d6f6c0d3..5307844a23 100644
>> --- a/docs/formatdomain.html.in
>> +++ b/docs/formatdomain.html.in
>> @@ -2064,6 +2064,7 @@
>> <xen>
>> <e820_host state='on'/>
>> <passthrough state='on' mode='share_pt'/>
>> + <gfx_passthru state='on'/>
>> </xen>
>> <pvspinlock state='on'/>
>> <gic version='2'/>
>> @@ -2270,6 +2271,12 @@
>> <td>on, off; mode - optional string sync_pt or share_pt</td>
>> <td><span class="since">6.3.0</span></td>
>> </tr>
>> + <tr>
>> + <td>gfx_passthru</td>
>> + <td>Enable Intel GPU specific quirks. Required and allowed
>> only when passing an IGD.</td>
>> + <td>on, off</td>
>> + <td><span class="since">6.3.0</span></td>
>> + </tr>
>> </table>
>> </dd>
>> <dt><code>pmu</code></dt>
>> diff --git a/docs/schemas/domaincommon.rng
>> b/docs/schemas/domaincommon.rng
>> index 9d60b090f3..7d8ea879a1 100644
>> --- a/docs/schemas/domaincommon.rng
>> +++ b/docs/schemas/domaincommon.rng
>> @@ -6409,6 +6409,11 @@
>> </optional>
>> </element>
>> </optional>
>> + <optional>
>> + <element name="gfx_passthru">
>> + <ref name="featurestate"/>
>> + </element>
>> + </optional>
>> </interleave>
>> </element>
>> </define>
>> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
>> index 8a87586936..75f72ff64c 100644
>> --- a/src/conf/domain_conf.c
>> +++ b/src/conf/domain_conf.c
>> @@ -214,6 +214,7 @@ VIR_ENUM_IMPL(virDomainXen,
>> VIR_DOMAIN_XEN_LAST,
>> "e820_host",
>> "passthrough",
>> + "gfx_passthru"
>> );
>> VIR_ENUM_IMPL(virDomainXenPassthroughMode,
>> @@ -19649,6 +19650,7 @@ virDomainFeaturesDefParse(virDomainDefPtr def,
>> switch ((virDomainXen) feature) {
>> case VIR_DOMAIN_XEN_E820_HOST:
>> + case VIR_DOMAIN_XEN_GFX_PASSTHRU:
>> break;
>> case VIR_DOMAIN_XEN_PASSTHROUGH:
>> @@ -23579,6 +23581,7 @@
>> virDomainDefFeaturesCheckABIStability(virDomainDefPtr src,
>> }
>> switch ((virDomainXen) i) {
>> case VIR_DOMAIN_XEN_E820_HOST:
>> + case VIR_DOMAIN_XEN_GFX_PASSTHRU:
>> break;
>> case VIR_DOMAIN_XEN_PASSTHROUGH:
>> @@ -29235,6 +29238,7 @@ virDomainDefFormatFeatures(virBufferPtr buf,
>> switch ((virDomainXen) j) {
>> case VIR_DOMAIN_XEN_E820_HOST:
>> + case VIR_DOMAIN_XEN_GFX_PASSTHRU:
>> virBufferAddLit(&childBuf, "/>\n");
>> break;
>> case VIR_DOMAIN_XEN_PASSTHROUGH:
>> diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
>> index 4afd8f04bc..f28f0741ac 100644
>> --- a/src/conf/domain_conf.h
>> +++ b/src/conf/domain_conf.h
>> @@ -1867,6 +1867,7 @@ typedef enum {
>> typedef enum {
>> VIR_DOMAIN_XEN_E820_HOST = 0,
>> VIR_DOMAIN_XEN_PASSTHROUGH,
>> + VIR_DOMAIN_XEN_GFX_PASSTHRU,
>> VIR_DOMAIN_XEN_LAST
>> } virDomainXen;
>> diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
>> index 458dfc2399..a5605f6200 100644
>> --- a/src/libxl/libxl_conf.c
>> +++ b/src/libxl/libxl_conf.c
>> @@ -679,6 +679,19 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
>> return -1;
>> }
>> #endif
>> + if (def->features[VIR_DOMAIN_FEATURE_XEN] ==
>> VIR_TRISTATE_SWITCH_ON) {
>> + switch ((virTristateSwitch)
>> def->xen_features[VIR_DOMAIN_XEN_GFX_PASSTHRU]) {
>> + case VIR_TRISTATE_SWITCH_ON:
>> + libxl_defbool_set(&b_info->u.hvm.gfx_passthru,
>> true);
>> + break;
>> + case VIR_TRISTATE_SWITCH_OFF:
>> + libxl_defbool_set(&b_info->u.hvm.gfx_passthru,
>> false);
>> + break;
>> + case VIR_TRISTATE_SWITCH_ABSENT:
>> + case VIR_TRISTATE_SWITCH_LAST:
>> + break;
>> + }
>> + }
>> } else if (pvh) {
>> b_info->cmdline = g_strdup(def->os.cmdline);
>> b_info->kernel = g_strdup(def->os.kernel);
>>
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