Hi
On Thu, Aug 08, 2019 at 01:53:23PM +0300, Oleksandr Tyshchenko wrote:
From: Oleksandr Tyshchenko <[email protected]>
Don't skip IOMMU nodes when creating DT for Dom0 if IOMMU has been
forcibly disabled in bootargs (e.g. "iommu=0") in order to let
the IOMMU be accessible by DOM0.
I don't think your code is doing what you expect... If iommu=0, then
Xen will not lookup for IOMMUs (iommu_hardware_setup() will not be
called). So none of the device will have DEVICE_IOMMU set and hence
they are already given to dom0.
But I think it is wrong to give the IOMMUs to Dom0 when iommu=0.
This is not the goal of this option. If you want to passthrough the
IOMMU to Dom0, then you should use the parameter
iommu_hwdom_passthrough.
However, I agree with Roger that giving the IOMMU to dom0 is a
pretty bad idea. So this should be fixed.
I fully agree with the arguments provided that it is a bad idea. So,
please consider that patch as not relevant.
But, I am not sure I follow the last sentence:
>>> If iommu=0, then Xen will not lookup for IOMMUs
(iommu_hardware_setup() will not be called). So none of the device
will have DEVICE_IOMMU set and hence they are already given to dom0.
I can see that devices have DEVICE_IOMMU set. Although, the IOMMU
driver is not in use, it is present and compatible matches. So, even
if iommu=0, the IOMMU devices are not given to Dom0, because of
skipped. Or I missed something?
I can't see how iommu_hardware_setup() can be called on staging when
iommu=0 as this is protected by a if ( iommu_enable ).
Can you please give a stack trace how this is called and the version
you use? WARN() should do it for you.
iommu_hardware_setup() is not called. But, devices have DEVICE_IOMMU
set, even if "iommu=0". I am based on "7d1460c xen/arm: optee: fix
compilation with GCC 4.8" + Stefano's reserved-memory series + my IPMMU
series.
--
Regards,
Oleksandr Tyshchenko
_______________________________________________
Xen-devel mailing list
[email protected]
https://lists.xenproject.org/mailman/listinfo/xen-devel
