Hi Will, Robin,
On 28-02-2023 09:51 am, Ganapatrao Kulkarni wrote:
When the host kernel is booted with iommu passthrough mode, PF and VFs
are enumerated with iommu/smmu domain set to bypass mode.
In bypass mode, ATS is not enabled on all VFs and associated PF.
When VFs are attached to a VM, the corresponding iommu domain is set to
SMMU translation mode and smmu-v3 driver try to enable the ATS and fails
due to invalid STU of a PF.
Adding a fix to configure STU of a PF while enumerating in passthrough
mode.
Any comments on this patch/series?
Signed-off-by: Ganapatrao Kulkarni <gankulkarni@xxxxxxxxxxxxxxxxxxxxxx>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 25 ++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index f2425b0f0cd6..b218ef0bf001 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2292,6 +2292,23 @@ static bool arm_smmu_ats_supported(struct arm_smmu_master *master)
return dev_is_pci(dev) && pci_ats_supported(to_pci_dev(dev));
}
+static void arm_smmu_ats_stu_init(struct arm_smmu_master *master)
+{
+ size_t stu;
+ struct pci_dev *pdev;
+ struct arm_smmu_device *smmu = master->smmu;
+
+ if (master->ats_enabled)
+ return;
+
+ /* Smallest Translation Unit: log2 of the smallest supported granule */
+ stu = __ffs(smmu->pgsize_bitmap);
+ pdev = to_pci_dev(master->dev);
+
+ if (pci_ats_stu_configure(pdev, stu))
+ dev_err(master->dev, "Failed to configure ATS STU (%zu)\n", stu);
+}
+
static void arm_smmu_enable_ats(struct arm_smmu_master *master)
{
size_t stu;
@@ -2404,6 +2421,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
struct arm_smmu_device *smmu;
struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
struct arm_smmu_master *master;
+ bool ats_supported;
if (!fwspec)
return -ENOENT;
@@ -2446,9 +2464,10 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
}
master->domain = smmu_domain;
+ ats_supported = arm_smmu_ats_supported(master);
if (smmu_domain->stage != ARM_SMMU_DOMAIN_BYPASS)
- master->ats_enabled = arm_smmu_ats_supported(master);
+ master->ats_enabled = ats_supported;
arm_smmu_install_ste_for_dev(master);
@@ -2458,6 +2477,10 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
arm_smmu_enable_ats(master);
+ /* Configure ATS STU of a PF in passthrough */
+ if (!master->ats_enabled && ats_supported)
+ arm_smmu_ats_stu_init(master);
+
out_unlock:
mutex_unlock(&smmu_domain->init_mutex);
return ret;
Thanks,
Ganapat
