From: liufeng1 <[email protected]>
Add a new PCI driver flag, RTE_PCI_DRV_NEED_IOVA_AS_PA, that allows a
driver to tell the PCI bus layer it cannot work with IOVA as VA and
must use IOVA as PA.
The existing RTE_PCI_DRV_NEED_IOVA_AS_VA flag already provides the
opposite requirement. Some PCI devices, however, are managed by a
kernel driver that uses an identity-mapped IOMMU domain (e.g. when the
kernel is booted with iommu=pt). The user-space PMD for such
devices
must use IOVA as PA, because the DMA addresses programmed by DPDK must
match the identity mapping programmed by the kernel driver.
Without this flag, a PCI driver bound to a non-VFIO/UIO kernel driver
has no way to force IOVA as PA. pci_device_iova_mode() returns
RTE_IOVA_DC for those devices, and rte_eal_init() then sees an enabled
IOMMU and selects RTE_IOVA_VA, which breaks identity-domain PMDs and
forces users to pass --iova-mode=pa on the command line.
When RTE_PCI_DRV_NEED_IOVA_AS_PA is set, pci_device_iova_mode()
returns RTE_IOVA_PA for the device. The requirement is propagated
through rte_pci_get_iommu_class() to rte_bus_get_iommu_class(), so
rte_eal_init() selects IOVA as PA automatically.
If a driver sets both RTE_PCI_DRV_NEED_IOVA_AS_VA and
RTE_PCI_DRV_NEED_IOVA_AS_PA at the same time, a warning is emitted
and the conflicting requirement is ignored (RTE_IOVA_DC), because
the two flags are mutually exclusive.
This is a generic mechanism: any PCI driver whose underlying kernel
driver uses an identity IOMMU domain can set the flag.
Signed-off-by: Jie Liu <[email protected]>
---
drivers/bus/pci/bus_pci_driver.h | 2 ++
drivers/bus/pci/linux/pci.c | 13 +++++++++++++
drivers/bus/pci/pci_common.c | 3 +--
3 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/drivers/bus/pci/bus_pci_driver.h b/drivers/bus/pci/bus_pci_driver.h
index c04ebddf59..5d5efbbb3e 100644
--- a/drivers/bus/pci/bus_pci_driver.h
+++ b/drivers/bus/pci/bus_pci_driver.h
@@ -140,6 +140,8 @@ struct rte_pci_driver {
#define RTE_PCI_DRV_KEEP_MAPPED_RES 0x0020
/** Device driver needs IOVA as VA and cannot work with IOVA as PA */
#define RTE_PCI_DRV_NEED_IOVA_AS_VA 0x0040
+/** Device driver needs IOVA as PA and cannot work with IOVA as VA */
+#define RTE_PCI_DRV_NEED_IOVA_AS_PA 0x0080
/**
* Register a PCI driver.
diff --git a/drivers/bus/pci/linux/pci.c b/drivers/bus/pci/linux/pci.c
index bcf0a409da..4e03d81ed2 100644
--- a/drivers/bus/pci/linux/pci.c
+++ b/drivers/bus/pci/linux/pci.c
@@ -595,6 +595,15 @@ pci_device_iova_mode(const struct rte_pci_driver *pdrv,
{
enum rte_iova_mode iova_mode = RTE_IOVA_DC;
+ if ((pdrv->drv_flags &
+ (RTE_PCI_DRV_NEED_IOVA_AS_VA | RTE_PCI_DRV_NEED_IOVA_AS_PA)) ==
+ (RTE_PCI_DRV_NEED_IOVA_AS_VA | RTE_PCI_DRV_NEED_IOVA_AS_PA)) {
+ RTE_LOG(WARNING, EAL,
+ "PCI driver '%s' sets both NEED_IOVA_AS_VA and
NEED_IOVA_AS_PA flags, ignoring\n",
+ pdrv->driver.name);
+ return iova_mode;
+ }
+
switch (pdev->kdrv) {
case RTE_PCI_KDRV_VFIO: {
static int is_vfio_noiommu_enabled = -1;
@@ -609,6 +618,8 @@ pci_device_iova_mode(const struct rte_pci_driver *pdrv,
iova_mode = RTE_IOVA_PA;
else if ((pdrv->drv_flags & RTE_PCI_DRV_NEED_IOVA_AS_VA) != 0)
iova_mode = RTE_IOVA_VA;
+ else if ((pdrv->drv_flags & RTE_PCI_DRV_NEED_IOVA_AS_PA) != 0)
+ iova_mode = RTE_IOVA_PA;
break;
}
@@ -620,6 +631,8 @@ pci_device_iova_mode(const struct rte_pci_driver *pdrv,
default:
if ((pdrv->drv_flags & RTE_PCI_DRV_NEED_IOVA_AS_VA) != 0)
iova_mode = RTE_IOVA_VA;
+ else if ((pdrv->drv_flags & RTE_PCI_DRV_NEED_IOVA_AS_PA) != 0)
+ iova_mode = RTE_IOVA_PA;
break;
}
return iova_mode;
diff --git a/drivers/bus/pci/pci_common.c b/drivers/bus/pci/pci_common.c
index dc8db80d3b..9893306c8e 100644
--- a/drivers/bus/pci/pci_common.c
+++ b/drivers/bus/pci/pci_common.c
@@ -533,8 +533,7 @@ rte_pci_get_iommu_class(void)
iommu_no_va = pci_device_iommu_support_va(dev)
? 0 : 1;
- if (dev->kdrv == RTE_PCI_KDRV_UNKNOWN ||
- dev->kdrv == RTE_PCI_KDRV_NONE)
+ if (dev->kdrv == RTE_PCI_KDRV_NONE)
continue;
RTE_BUS_FOREACH_DRV(drv, &rte_pci_bus) {
enum rte_iova_mode dev_iova_mode;
--
2.52.0
