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Subject[PATCH] iommu/amd - Set the device table entry PPR bit for IOMMU V2 devices
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Date
The AMD IOMMU specification Rev 3.00 (December 2016) introduces a
new Enhanced PPR Handling Support (EPHSup) bit in the MMIO register
offset 0030h (IOMMU Extended Feature Register).

When EPHSup=1, the IOMMU hardware requires the PPR bit of the
device table entry (DTE) to be set in order to support PPR for a
particular endpoint device.

Please see https://support.amd.com/TechDocs/48882_IOMMU.pdf for
this revision of the AMD IOMMU specification.

Signed-off-by: Gary R Hook <gary.hook@amd.com>
---
drivers/iommu/amd_iommu.c | 20 +++++++++++++++-----
drivers/iommu/amd_iommu_types.h | 2 ++
2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index cb78933ef53f..329940ffb8c1 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1818,7 +1818,8 @@ static bool dma_ops_domain(struct protection_domain *domain)
return domain->flags & PD_DMA_OPS_MASK;
}

-static void set_dte_entry(u16 devid, struct protection_domain *domain, bool ats)
+static void set_dte_entry(u16 devid, struct protection_domain *domain,
+ bool ats, bool ppr)
{
u64 pte_root = 0;
u64 flags = 0;
@@ -1835,6 +1836,13 @@ static void set_dte_entry(u16 devid, struct protection_domain *domain, bool ats)
if (ats)
flags |= DTE_FLAG_IOTLB;

+ if (ppr) {
+ struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];
+
+ if (iommu_feature(iommu, FEATURE_EPHSUP))
+ pte_root |= DEV_ENTRY_PPR;
+ }
+
if (domain->flags & PD_IOMMUV2_MASK) {
u64 gcr3 = iommu_virt_to_phys(domain->gcr3_tbl);
u64 glx = domain->glx;
@@ -1897,9 +1905,9 @@ static void do_attach(struct iommu_dev_data *dev_data,
domain->dev_cnt += 1;

/* Update device table */
- set_dte_entry(dev_data->devid, domain, ats);
+ set_dte_entry(dev_data->devid, domain, ats, dev_data->iommu_v2);
if (alias != dev_data->devid)
- set_dte_entry(alias, domain, ats);
+ set_dte_entry(alias, domain, ats, dev_data->iommu_v2);

device_flush_dte(dev_data);
}
@@ -2278,13 +2286,15 @@ static void update_device_table(struct protection_domain *domain)
struct iommu_dev_data *dev_data;

list_for_each_entry(dev_data, &domain->dev_list, list) {
- set_dte_entry(dev_data->devid, domain, dev_data->ats.enabled);
+ set_dte_entry(dev_data->devid, domain, dev_data->ats.enabled,
+ dev_data->iommu_v2);

if (dev_data->devid == dev_data->alias)
continue;

/* There is an alias, update device table entry for it */
- set_dte_entry(dev_data->alias, domain, dev_data->ats.enabled);
+ set_dte_entry(dev_data->alias, domain, dev_data->ats.enabled,
+ dev_data->iommu_v2);
}
}

diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index f6b24c7d8b70..6a877ebd058b 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -98,6 +98,7 @@
#define FEATURE_HE (1ULL<<8)
#define FEATURE_PC (1ULL<<9)
#define FEATURE_GAM_VAPIC (1ULL<<21)
+#define FEATURE_EPHSUP (1ULL<<50)

#define FEATURE_PASID_SHIFT 32
#define FEATURE_PASID_MASK (0x1fULL << FEATURE_PASID_SHIFT)
@@ -192,6 +193,7 @@
/* macros and definitions for device table entries */
#define DEV_ENTRY_VALID 0x00
#define DEV_ENTRY_TRANSLATION 0x01
+#define DEV_ENTRY_PPR 0x34
#define DEV_ENTRY_IR 0x3d
#define DEV_ENTRY_IW 0x3e
#define DEV_ENTRY_NO_PAGE_FAULT 0x62
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