Linux Virtualization - Feb 2020 - [PATCH] iommu/virtio: Build virtio-iommu as module

From: Jean-Philippe Brucker <jean-philippe.brucker at arm.com>

Now that the infrastructure changes are in place, enable virtio-iommu to
be built as a module. Remove the redundant pci_request_acs() call, since
it's not exported but is already invoked during DMA setup.

Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker at arm.com>
---
This conflicts with the multiplatform work [1] since they both change
Kconfig. Locally I have this patch applied on top of that series but
there is no functional dependency between the two.

[1] https://lore.kernel.org/linux-iommu/20200214160413.1475396-1-jean-philippe
at linaro.org/
---
 drivers/iommu/Kconfig        | 4 ++--
 drivers/iommu/virtio-iommu.c | 1 -
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index adcbda44d473..bfd4e5fcd6aa 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -506,8 +506,8 @@ config HYPERV_IOMMU
 	  guests to run with x2APIC mode enabled.
 
 config VIRTIO_IOMMU
-	bool "Virtio IOMMU driver"
-	depends on VIRTIO=y
+	tristate "Virtio IOMMU driver"
+	depends on VIRTIO
 	depends on (ARM64 || X86)
 	select IOMMU_API
 	select IOMMU_DMA
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index f18ba8e22ebd..5429c12c879b 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -1084,7 +1084,6 @@ static int viommu_probe(struct virtio_device *vdev)
 
 #ifdef CONFIG_PCI
 	if (pci_bus_type.iommu_ops != &viommu_ops) {
-		pci_request_acs();
 		ret = bus_set_iommu(&pci_bus_type, &viommu_ops);
 		if (ret)
 			goto err_unregister;
-- 
2.25.0

On Fri, Feb 14, 2020 at 05:38:27PM +0100, Jean-Philippe Brucker
wrote:
> From: Jean-Philippe Brucker <jean-philippe.brucker at arm.com>
> 
> Now that the infrastructure changes are in place, enable virtio-iommu to
> be built as a module. Remove the redundant pci_request_acs() call, since
> it's not exported but is already invoked during DMA setup.
Which infrastructure changes do you mean? Does this depend on the x86
enablement patch-set in any way?


Regards,

	Joerg

Hi Joerg,

On Wed, Feb 19, 2020 at 12:16:04PM +0100, Joerg Roedel
wrote:
> On Fri, Feb 14, 2020 at 05:38:27PM +0100, Jean-Philippe Brucker wrote:
> > From: Jean-Philippe Brucker <jean-philippe.brucker at arm.com>
> > 
> > Now that the infrastructure changes are in place, enable virtio-iommu
to
> > be built as a module. Remove the redundant pci_request_acs() call,
since
> > it's not exported but is already invoked during DMA setup.
> 
> Which infrastructure changes do you mean? Does this depend on the x86
> enablement patch-set in any way?
No, I meant Will's changes in 5.6 to make the SMMU drivers modular. This
patch doesn't depend on the x86 enablement patch-set, but there is a small
conflict in Kconfig since they both modify it (locally I have this patch
applied on top of the x86 enablement).

Thanks,
Jean