Re: [help] Xen 4.14.5 on Devuan 4.0 Chimaera, regression from Xen 4.0.1

[Denis <tachyon_gun@xxxxxx>]

On 14.03.2023 16:11, Andrew Cooper wrote:
> On 14/03/2023 2:53 pm, Denis wrote:
> > On 14.03.2023 07:37; Jan Beulich wrote:
> >> On 14.03.2023 02:15, Denis wrote:
> >>> On 13.03.2023 10:36, Jan wrote
> >>>> On 10.03.2023 21:50, Denis wrote:
> >>>>> Should I test something else?
> >>>> ... there was no request for any further testing here, for the moment.
> >>> ah...sorry, going by "Would be nice to have this confirmed forthe system
> >>> in question, i.e. without Xen underneath Linux" I thought I could test
> >>> something which might help shed some light on all of this.
> >> Well, yes, that Linux-without-Xen test would still be useful to have
> >> results from. I didn't account for this in my earlier reply because
> >> I had asked for it before already, and I did take "something else"
> >> for meaning anything that might have turned up as useful from the new
> >> data you had provided.
> > What tests could I do or what info should I provide to help?
> 
> Can you please rebuild Xen with this patch:
> 
> diff --git a/xen/drivers/passthrough/amd/iommu_acpi.c
> b/xen/drivers/passthrough/amd/iommu_acpi.c
> index 2fdebd2d74c9..747eae25f56c 100644
> --- a/xen/drivers/passthrough/amd/iommu_acpi.c
> +++ b/xen/drivers/passthrough/amd/iommu_acpi.c
> @@ -1033,7 +1033,7 @@ static int __init parse_ivrs_table(struct
> acpi_table_header *table)
>      const struct acpi_ivrs_header *ivrs_block;
>      unsigned long length;
>      unsigned int apic;
> -    bool_t sb_ioapic = !iommu_intremap;
> +    bool_t sb_ioapic = 1;
>      int error = 0;
>  
>      BUG_ON(!table);
> 
> which should cause the behaviour to revert back to that of Xen 4.0.1 
> (i.e. it will fully ignore the checks relating to the southbridge ioapic).
> 
> Confirm that with this, and booting Xen simply with `iommu=1` that full
> DMA remapping and interrupt remapping is considered active.
> 
> 
> Then, can you play around with passing the soundblaster through to VMs. 
> Looking at the LSPCI you provided, it only supports legacy line interrupts.
> 
> Does the device work fine, or do you get a bunch of errors on `xl dmesg`
> about IO page faults (which is a generic "IOMMU said no to something"
> message)?

Am I right to assume that I would need the source/header packages from 
the Devuan 4.0 install and then re-compile Xen?

Denis