Re: [PATCH v3 7/8] iommu/amd: Add debugfs support to dump IRT Table

[Dheeraj Kumar Srivastava]

Hi Vasant,

On 3/13/2025 4:33 PM, Vasant Hegde wrote:
> Hi,
>
>
> On 2/6/2025 11:30 AM, Dheeraj Kumar Srivastava wrote:
> > In cases where we have an issue in the device interrupt path with IOMMU
> > interrupt remapping enabled, dumping valid IRT table entries for the device
> > is very useful and good input for debugging the issue.
> >
> > eg.
> > To dump irte entries for a particular device
> >     #echo "c4:00.0" > /sys/kernel/debug/iommu/amd/devid
> >     #cat /sys/kernel/debug/iommu/amd/irqtbl | less
> >
> >     or
> >
> >     #echo "0000:c4:00.0" > /sys/kernel/debug/iommu/amd/devid
> >     #cat /sys/kernel/debug/iommu/amd/irqtbl | less
> >
> > Signed-off-by: Dheeraj Kumar Srivastava <dheerajkumar.srivastava@xxxxxxx>
> > ---
> >   drivers/iommu/amd/debugfs.c | 89 +++++++++++++++++++++++++++++++++++++
> >   1 file changed, 89 insertions(+)
> >
> > diff --git a/drivers/iommu/amd/debugfs.c b/drivers/iommu/amd/debugfs.c
> > index 1377795814d1..0aff1d616108 100644
> > --- a/drivers/iommu/amd/debugfs.c
> > +++ b/drivers/iommu/amd/debugfs.c
> > @@ -11,6 +11,7 @@
> >   #include <linux/pci.h>
> >   
> >   #include "amd_iommu.h"
> > +#include "../irq_remapping.h"
> >   
> >   static struct dentry *amd_iommu_debugfs;
> >   
> > @@ -250,6 +251,92 @@ static int iommu_devtbl_show(struct seq_file *m, void *unused)
> >   }
> >   DEFINE_SHOW_ATTRIBUTE(iommu_devtbl);
> >   
> > +static void dump_128_irte(struct seq_file *m, struct irq_remap_table *table)
> > +{
> > +	struct irte_ga *ptr, *irte;
> > +	int index;
> > +
> > +	for (index = 0; index < MAX_IRQS_PER_TABLE; index++) {
> > +		ptr = (struct irte_ga *)table->table;
> > +		irte = &ptr[index];
> > +
> > +		if (AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir) &&
> > +		    !irte->lo.fields_vapic.valid)
> > +			continue;
> > +		else if (!irte->lo.fields_remap.valid)
> > +			continue;
> > +		seq_printf(m, "IRT[%04d] %016llx%016llx\n", index, irte->hi.val, irte->lo.val);
>
> Can you please space between words so that its easy to read?

Sure. Will update in v4.

Thanks
Dheeraj

> -Vasant