ACPI: VIOT: Initialize the correct IOMMU fwspec

When setting up DMA for a PCI device, we need to initialize its
iommu_fwspec with all possible alias RIDs (such as PCI bridges). To do
this we use pci_for_each_dma_alias() which calls
viot_pci_dev_iommu_init(). This function incorrectly initializes the
fwspec of the bridge instead of the device being configured. Fix it by
passing the original device as context to pci_for_each_dma_alias().

Fixes: 3cf485540e7b ("ACPI: Add driver for the VIOT table")
Link: https://lore.kernel.org/all/Y8qzOKm6kvhGWG1T@myrica
Reported-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

iommu/dma: Make header private

Now that dma-iommu.h only contains internal interfaces, make it
private to the IOMMU subsytem.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/b237e06c56a101f77af142a54b629b27aa179d22.1660668998.git.robin.murphy@arm.com
[ joro : re-add stub for iommu_dma_get_resv_regions ]
Signed-off-by: Joerg Roedel <jroedel@suse.de>

ACPI: VIOT: Do not dereference fwnode in struct device

In order to make the underneath API easier to change in the future,
prevent users from dereferencing fwnode from struct device.
Instead, use the specific dev_fwnode() and device_match_fwnode()
APIs for that.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: VIOT: Fix ACS setup

Currently acpi_viot_init() gets called after the pci
device has been scanned and pci_enable_acs() has been called.
So pci_request_acs() fails to be taken into account leading
to wrong single iommu group topologies when dealing with
multi-function root ports for instance.

We cannot simply move the acpi_viot_init() earlier, similarly
as the IORT init because the VIOT parsing relies on the pci
scan. However we can detect VIOT is present earlier and in
such a case, request ACS. Introduce a new acpi_viot_early_init()
routine that allows to call pci_request_acs() before the scan.

While at it, guard the call to pci_request_acs() with #ifdef
CONFIG_PCI.

Fixes: 3cf485540e7b ("ACPI: Add driver for the VIOT table")
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reported-by: Jin Liu <jinl@redhat.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Tested-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: Add driver for the VIOT table

The ACPI Virtual I/O Translation Table describes topology of
para-virtual platforms, similarly to vendor tables DMAR, IVRS and IORT.
For now it describes the relation between virtio-iommu and the endpoints
it manages.

Three steps are needed to configure DMA of endpoints:

(1) acpi_viot_init(): parse the VIOT table, find or create the fwnode
associated to each vIOMMU device. This needs to happen after
acpi_scan_init(), because it relies on the struct device and their
fwnode to be available.

(2) When probing the vIOMMU device, the driver registers its IOMMU ops
within the IOMMU subsystem. This step doesn't require any
intervention from the VIOT driver.

(3) viot_iommu_configure(): before binding the endpoint to a driver,
find the associated IOMMU ops. Register them, along with the
endpoint ID, into the device's iommu_fwspec.

If step (3) happens before step (2), it is deferred until the IOMMU is
initialized, then retried.

Tested-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20210618152059.1194210-4-jean-philippe@linaro.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>