This enables IOMMU support for pseries Secure VMs.
Signed-off-by: Ram Pai <[email protected]>
---
arch/powerpc/platforms/pseries/iommu.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 07f0847..189717b 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -1333,15 +1333,7 @@ void iommu_init_early_pSeries(void)
of_reconfig_notifier_register(&iommu_reconfig_nb);
register_memory_notifier(&iommu_mem_nb);
- /*
- * Secure guest memory is inacessible to devices so regular DMA isn't
- * possible.
- *
- * In that case keep devices' dma_map_ops as NULL so that the generic
- * DMA code path will use SWIOTLB to bounce buffers for DMA.
- */
- if (!is_secure_guest())
- set_pci_dma_ops(&dma_iommu_ops);
+ set_pci_dma_ops(&dma_iommu_ops);
}
static int __init disable_multitce(char *str)
--
1.8.3.1
Ram Pai <[email protected]> writes:
> This enables IOMMU support for pseries Secure VMs.
Can you give us some more explanation please?
This is basically a revert of commit:
edea902c1c1e ("powerpc/pseries/iommu: Don't use dma_iommu_ops on secure guests")
But neglects to remove the now unnecessary include of svm.h.
> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> index 07f0847..189717b 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -1333,15 +1333,7 @@ void iommu_init_early_pSeries(void)
> of_reconfig_notifier_register(&iommu_reconfig_nb);
> register_memory_notifier(&iommu_mem_nb);
>
> - /*
> - * Secure guest memory is inacessible to devices so regular DMA isn't
> - * possible.
> - *
> - * In that case keep devices' dma_map_ops as NULL so that the generic
> - * DMA code path will use SWIOTLB to bounce buffers for DMA.
Please explain what has changed to make this no longer necessary.
cheers
> - */
> - if (!is_secure_guest())
> - set_pci_dma_ops(&dma_iommu_ops);
> + set_pci_dma_ops(&dma_iommu_ops);
> }
>
> static int __init disable_multitce(char *str)
> --
> 1.8.3.1
On Thu, Nov 07, 2019 at 09:26:28PM +1100, Michael Ellerman wrote:
> Ram Pai <[email protected]> writes:
> > This enables IOMMU support for pseries Secure VMs.
>
> Can you give us some more explanation please?
Yes. Will do.
The simple explanation is -- it was a mistake. We should
not have disabled IOMMU ops for secure guests. Though it enabled
us to use virtio devices, with the help of some additional patches to
the virtio subsystem; in hindsight, we should not have disabled IOMMU
ops for secure VMs :-(.
RP
>
> This is basically a revert of commit:
> edea902c1c1e ("powerpc/pseries/iommu: Don't use dma_iommu_ops on secure guests")
>
> But neglects to remove the now unnecessary include of svm.h.
>
> > diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> > index 07f0847..189717b 100644
> > --- a/arch/powerpc/platforms/pseries/iommu.c
> > +++ b/arch/powerpc/platforms/pseries/iommu.c
> > @@ -1333,15 +1333,7 @@ void iommu_init_early_pSeries(void)
> > of_reconfig_notifier_register(&iommu_reconfig_nb);
> > register_memory_notifier(&iommu_mem_nb);
> >
> > - /*
> > - * Secure guest memory is inacessible to devices so regular DMA isn't
> > - * possible.
> > - *
> > - * In that case keep devices' dma_map_ops as NULL so that the generic
> > - * DMA code path will use SWIOTLB to bounce buffers for DMA.
>
> Please explain what has changed to make this no longer necessary.
>
> cheers
>
> > - */
> > - if (!is_secure_guest())
> > - set_pci_dma_ops(&dma_iommu_ops);
> > + set_pci_dma_ops(&dma_iommu_ops);
> > }
> >
> > static int __init disable_multitce(char *str)
> > --
> > 1.8.3.1
--
Ram Pai