At the moment the iommu_table struct has a set_bypass() which enables/
disables DMA bypass on IODA2 PHB. This is exposed to POWERPC IOMMU code
which calls this callback when external IOMMU users such as VFIO are
about to get over a PHB.
The set_bypass() callback is not really an iommu_table function but
IOMMU/PE function. This introduces a powerpc_iommu_ops struct and
adds a set_ownership() callback to it which is called when an external
user takes control over the IOMMU.
This renames set_bypass() to set_ownership() as it is not necessarily
just enabling bypassing, it can be something else/more so let's give it
more generic name. The bool parameter is inverted.
The callback is implemented for IODA2 only.
This replaces iommu_take_ownership()/iommu_release_ownership() calls
with the callback calls and it is up to the platform code to call
iommu_take_ownership()/iommu_release_ownership() if needed. Next patches
will remove these calls from IODA2 code.
Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
---
arch/powerpc/include/asm/iommu.h | 18 +++++++++--
arch/powerpc/kernel/iommu.c | 53 +++++++++++++++++++++++--------
arch/powerpc/platforms/powernv/pci-ioda.c | 30 ++++++++++++-----
drivers/vfio/vfio_iommu_spapr_tce.c | 23 ++++++++++----
4 files changed, 92 insertions(+), 32 deletions(-)
diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 4fe5555..ba16aa0 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -92,7 +92,6 @@ struct iommu_table {
unsigned long it_page_shift;/* table iommu page size */
struct powerpc_iommu *it_iommu;
struct iommu_table_ops *it_ops;
- void (*set_bypass)(struct iommu_table *tbl, bool enable);
};
/* Pure 2^n version of get_order */
@@ -127,11 +126,24 @@ extern struct iommu_table *iommu_init_table(struct
iommu_table * tbl,
#define POWERPC_IOMMU_MAX_TABLES 1
+struct powerpc_iommu;
+
+struct powerpc_iommu_ops {
+ /*
+ * Switches ownership from the kernel itself to an external
+ * user. While onwership is enabled, the kernel cannot use IOMMU
+ * for itself.
+ */
+ void (*set_ownership)(struct powerpc_iommu *iommu,
+ bool enable);
+};
+
struct powerpc_iommu {
#ifdef CONFIG_IOMMU_API
struct iommu_group *group;
#endif
struct iommu_table tables[POWERPC_IOMMU_MAX_TABLES];
+ struct powerpc_iommu_ops *ops;
};
#ifdef CONFIG_IOMMU_API
@@ -219,8 +231,8 @@ extern unsigned long iommu_clear_tce(struct iommu_table
*tbl,
unsigned long entry);
extern void iommu_flush_tce(struct iommu_table *tbl);
-extern int iommu_take_ownership(struct iommu_table *tbl);
-extern void iommu_release_ownership(struct iommu_table *tbl);
+extern int iommu_take_ownership(struct powerpc_iommu *iommu);
+extern void iommu_release_ownership(struct powerpc_iommu *iommu);
#endif /* __KERNEL__ */
#endif /* _ASM_IOMMU_H */
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 407d0d6..9d06425 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1022,7 +1022,7 @@ int iommu_tce_build(struct iommu_table *tbl, unsigned
long entry,
}
EXPORT_SYMBOL_GPL(iommu_tce_build);
-int iommu_take_ownership(struct iommu_table *tbl)
+static int iommu_table_take_ownership(struct iommu_table *tbl)
{
unsigned long flags, i, sz = (tbl->it_size + 7) >> 3;
int ret = 0;
@@ -1047,19 +1047,36 @@ int iommu_take_ownership(struct iommu_table *tbl)
spin_unlock(&tbl->pools[i].lock);
spin_unlock_irqrestore(&tbl->large_pool.lock, flags);
- /*
- * Disable iommu bypass, otherwise the user can DMA to all of
- * our physical memory via the bypass window instead of just
- * the pages that has been explicitly mapped into the iommu
- */
- if (!ret && tbl->set_bypass)
- tbl->set_bypass(tbl, false);
-
- return ret;
+ return 0;
+}
+
+static void iommu_table_release_ownership(struct iommu_table *tbl);
+
+int iommu_take_ownership(struct powerpc_iommu *iommu)
+{
+ int i, j, rc = 0;
+
+ for (i = 0; i < POWERPC_IOMMU_MAX_TABLES; ++i) {
+ struct iommu_table *tbl = &iommu->tables[i];
+
+ if (!tbl->it_map)
+ continue;
+
+ rc = iommu_table_take_ownership(tbl);
+ if (rc) {
+ for (j = 0; j < i; ++j)
+ iommu_table_release_ownership(
+ &iommu->tables[j]);
+
+ return rc;
+ }
+ }
+
+ return 0;
}
EXPORT_SYMBOL_GPL(iommu_take_ownership);
-void iommu_release_ownership(struct iommu_table *tbl)
+static void iommu_table_release_ownership(struct iommu_table *tbl)
{
unsigned long flags, i, sz = (tbl->it_size + 7) >> 3;
@@ -1076,10 +1093,18 @@ void iommu_release_ownership(struct iommu_table *tbl)
for (i = 0; i < tbl->nr_pools; i++)
spin_unlock(&tbl->pools[i].lock);
spin_unlock_irqrestore(&tbl->large_pool.lock, flags);
+}
- /* The kernel owns the device now, we can restore the iommu bypass */
- if (tbl->set_bypass)
- tbl->set_bypass(tbl, true);
+extern void iommu_release_ownership(struct powerpc_iommu *iommu)
+{
+ int i;
+
+ for (i = 0; i < POWERPC_IOMMU_MAX_TABLES; ++i) {
+ struct iommu_table *tbl = &iommu->tables[i];
+
+ if (tbl->it_map)
+ iommu_table_release_ownership(tbl);
+ }
}
EXPORT_SYMBOL_GPL(iommu_release_ownership);
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c
b/arch/powerpc/platforms/powernv/pci-ioda.c
index 8ab00e3..a33a116 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1231,10 +1231,8 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb
*phb,
__free_pages(tce_mem, get_order(TCE32_TABLE_SIZE * segs));
}
-static void pnv_pci_ioda2_set_bypass(struct iommu_table *tbl, bool enable)
+static void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable)
{
- struct pnv_ioda_pe *pe = container_of(tbl->it_iommu, struct pnv_ioda_pe,
- iommu);
uint16_t window_id = (pe->pe_number << 1 ) + 1;
int64_t rc;
@@ -1262,7 +1260,8 @@ static void pnv_pci_ioda2_set_bypass(struct iommu_table
*tbl, bool enable)
* host side.
*/
if (pe->pdev)
- set_iommu_table_base(&pe->pdev->dev, tbl);
+ set_iommu_table_base(&pe->pdev->dev,
+ &pe->iommu.tables[0]);
else
pnv_ioda_setup_bus_dma(pe, pe->pbus, false);
}
@@ -1278,13 +1277,27 @@ static void pnv_pci_ioda2_setup_bypass_pe(struct
pnv_phb *phb,
/* TVE #1 is selected by PCI address bit 59 */
pe->tce_bypass_base = 1ull << 59;
- /* Install set_bypass callback for VFIO */
- pe->iommu.tables[0].set_bypass = pnv_pci_ioda2_set_bypass;
-
/* Enable bypass by default */
- pnv_pci_ioda2_set_bypass(&pe->iommu.tables[0], true);
+ pnv_pci_ioda2_set_bypass(pe, true);
}
+static void pnv_ioda2_set_ownership(struct powerpc_iommu *iommu,
+ bool enable)
+{
+ struct pnv_ioda_pe *pe = container_of(iommu, struct pnv_ioda_pe,
+ iommu);
+ if (enable)
+ iommu_take_ownership(iommu);
+ else
+ iommu_release_ownership(iommu);
+
+ pnv_pci_ioda2_set_bypass(pe, !enable);
+}
+
+static struct powerpc_iommu_ops pnv_pci_ioda2_ops = {
+ .set_ownership = pnv_ioda2_set_ownership,
+};
+
static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
struct pnv_ioda_pe *pe)
{
@@ -1352,6 +1365,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb
*phb,
}
tbl->it_ops = &pnv_iommu_ops;
iommu_init_table(tbl, phb->hose->node);
+ pe->iommu.ops = &pnv_pci_ioda2_ops;
iommu_register_group(&pe->iommu, phb->hose->global_number,
pe->pe_number);
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c
b/drivers/vfio/vfio_iommu_spapr_tce.c
index 9205264..5a22ff6 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -784,7 +784,7 @@ static long tce_iommu_ioctl(void *iommu_data,
static int tce_iommu_attach_group(void *iommu_data,
struct iommu_group *iommu_group)
{
- int ret;
+ int ret = 0;
struct tce_container *container = iommu_data;
struct powerpc_iommu *iommu;
@@ -803,12 +803,19 @@ static int tce_iommu_attach_group(void *iommu_data,
ret = -EBUSY;
} else {
iommu = iommu_group_get_iommudata(iommu_group);
- if (WARN_ON_ONCE(!iommu))
- return -ENXIO;
-
- ret = iommu_take_ownership(&iommu->tables[0]);
- if (!ret)
+ if (WARN_ON_ONCE(!iommu)) {
+ ret = -ENXIO;
+ } else if (iommu->ops && iommu->ops->set_ownership) {
+ /*
+ * Disable iommu bypass, otherwise the user can DMA to
all of
+ * our physical memory via the bypass window instead of
just
+ * the pages that has been explicitly mapped into the
iommu
+ */
+ iommu->ops->set_ownership(iommu, true);
container->grp = iommu_group;
+ } else {
+ ret = -ENODEV;
+ }
}
mutex_unlock(&container->lock);
@@ -841,7 +848,9 @@ static void tce_iommu_detach_group(void *iommu_data,
iommu = iommu_group_get_iommudata(iommu_group);
BUG_ON(!iommu);
- iommu_release_ownership(&iommu->tables[0]);
+ /* Kernel owns the device now, we can restore bypass */
+ if (iommu->ops && iommu->ops->set_ownership)
+ iommu->ops->set_ownership(iommu, false);
}
mutex_unlock(&container->lock);
}
--
2.0.0
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