On 2023-05-16 01:00, Jason Gunthorpe wrote:
Robin was able to check the documentation and what fsl_pamu has
historically called detach_dev() is really putting the IOMMU into an
IDENTITY mode.
Unfortunately it was the other way around - it's the call to
fsl_setup_liodns() from fsl_pamu_probe() which leaves everything in
bypass by default (the PAACE_ATM_NO_XLATE part, IIRC), whereas the
detach_device() call here ends up disabling the given device's LIODN
altogether. There doesn't appear to have ever been any code anywhere for
putting things *back* into bypass after using a VFIO domain, so as-is
these default domains would probably break all DMA :(
Thanks,
Robin.
Move to the new core support for ARM_DMA_USE_IOMMU by defining
ops->identity_domain. This is a ppc driver without any dma_ops, so ensure
the identity translation is the default domain.
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
drivers/iommu/fsl_pamu_domain.c | 32 +++++++++++++++++++++++++++++---
1 file changed, 29 insertions(+), 3 deletions(-)
diff --git a/drivers/iommu/fsl_pamu_domain.c b/drivers/iommu/fsl_pamu_domain.c
index bce37229709965..ca4f5ebf028783 100644
--- a/drivers/iommu/fsl_pamu_domain.c
+++ b/drivers/iommu/fsl_pamu_domain.c
@@ -283,15 +283,21 @@ static int fsl_pamu_attach_device(struct iommu_domain *domain,
return ret;
}
-static void fsl_pamu_set_platform_dma(struct device *dev)
+static int fsl_pamu_identity_attach(struct iommu_domain *platform_domain,
+ struct device *dev)
{
struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
- struct fsl_dma_domain *dma_domain = to_fsl_dma_domain(domain);
+ struct fsl_dma_domain *dma_domain;
const u32 *prop;
int len;
struct pci_dev *pdev = NULL;
struct pci_controller *pci_ctl;
+ if (domain == platform_domain || !domain)
+ return 0;
+
+ dma_domain = to_fsl_dma_domain(domain);
+
/*
* Use LIODN of the PCI controller while detaching a
* PCI device.
@@ -312,8 +318,18 @@ static void fsl_pamu_set_platform_dma(struct device *dev)
detach_device(dev, dma_domain);
else
pr_debug("missing fsl,liodn property at %pOF\n", dev->of_node);
+ return 0;
}
+static struct iommu_domain_ops fsl_pamu_identity_ops = {
+ .attach_dev = fsl_pamu_identity_attach,
+};
+
+static struct iommu_domain fsl_pamu_identity_domain = {
+ .type = IOMMU_DOMAIN_IDENTITY,
+ .ops = &fsl_pamu_identity_ops,
+};
+
/* Set the domain stash attribute */
int fsl_pamu_configure_l1_stash(struct iommu_domain *domain, u32 cpu)
{
@@ -447,12 +463,22 @@ static struct iommu_device *fsl_pamu_probe_device(struct device *dev)
return &pamu_iommu;
}
+static int fsl_pamu_def_domain_type(struct device *dev)
+{
+ /*
+ * This platform does not use dma_ops at all so the normally the iommu
+ * must be in identity mode
+ */
+ return IOMMU_DOMAIN_IDENTITY;
+}
+
static const struct iommu_ops fsl_pamu_ops = {
+ .identity_domain = &fsl_pamu_identity_domain,
+ .def_domain_type = &fsl_pamu_def_domain_type,
.capable = fsl_pamu_capable,
.domain_alloc = fsl_pamu_domain_alloc,
.probe_device = fsl_pamu_probe_device,
.device_group = fsl_pamu_device_group,
- .set_platform_dma_ops = fsl_pamu_set_platform_dma,
.default_domain_ops = &(const struct iommu_domain_ops) {
.attach_dev = fsl_pamu_attach_device,
.iova_to_phys = fsl_pamu_iova_to_phys,
