On 8/4/25 12:56 PM, Mohamed Mediouni wrote:
On 4. Aug 2025, at 21:50, Pierrick Bouvier
<pierrick.bouv...@linaro.org> wrote:
On 8/4/25 7:23 AM, Mohamed Mediouni wrote:
Windows Hypervisor Platform's vGIC doesn't support ITS.
Deal with this by reporting to the user and not creating the ITS device.
Signed-off-by: Mohamed Mediouni <moha...@unpredictable.fr>
---
hw/arm/virt.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 98a1c74c42..0039f6a12b 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -741,6 +741,16 @@ static void create_its(VirtMachineState *vms)
return;
}
+ if (whpx_enabled() && vms->tcg_its) {
+ /*
+ * Signal to the user when ITS is neither supported by the host
+ * nor emulated by the machine.
+ */
+ info_report("ITS not supported on WHPX.");
+ info_report("To support MSIs, use its=off to enable GICv3 +
GICv2m.");
+ return;
+ }
+
dev = qdev_new(its_class_name());
object_property_set_link(OBJECT(dev), "parent-gicv3",
OBJECT(vms->gic),
Is it equivalent to simply using its=off, or is there a difference?
The info_report seems to imply it's not the same.
Not equivalent.
Regular system: GICv3 + ITS
This configuration (for the newest machine version): GICv3 with no MSIs
And its=off explicitly: GICv3 + GICv2m
It became not equivalent since the intro of GICv3 + GICv2m in patch 2 of
this series.
Thank you,
I see. It could be worth adding this information to commit message.
With that,
Reviewed-by: Pierrick Bouvier <pierrick.bouv...@linaro.org>
Slightly off topic for this commit, is there any downside to always have
GICv3 + GICv2m setup enabled? Do some systems don't support GICv2m?
Thanks,
Pierrick
