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dmaengine: idxd: add module parameter to force disable of SVA 

Add a module parameter that overrides the SVA feature enabling. This keeps
the driver in legacy mode even when intel_iommu=sm_on is set. In this mode,
the descriptor fields must be programmed with dma_addr_t from the Linux DMA
API for source, destination, and completion descriptors.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/161134110457.4005461.13171197785259115852.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Dave Jiang 2021-01-22 11:46:00 -07:00 committed by Vinod Koul
parent 9f3c14d443
commit 03d939c7e3
2 changed files with 13 additions and 1 deletions
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6
Documentation/admin-guide/kernel-parameters.txt
View File

@ -1673,6 +1673,12 @@
In such case C2/C3 won't be used again.
idle=nomwait: Disable mwait for CPU C-states
idxd.sva= [HW]
Format: <bool>
Allow force disabling of Shared Virtual Memory (SVA)
support for the idxd driver. By default it is set to
true (1).
ieee754= [MIPS] Select IEEE Std 754 conformance mode
Format: { strict | legacy | 2008 | relaxed }
Default: strict

8
drivers/dma/idxd/init.c
View File

@ -26,6 +26,10 @@ MODULE_VERSION(IDXD_DRIVER_VERSION);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Intel Corporation");
static bool sva = true;
module_param(sva, bool, 0644);
MODULE_PARM_DESC(sva, "Toggle SVA support on/off");
#define DRV_NAME "idxd"
bool support_enqcmd;
@ -338,12 +342,14 @@ static int idxd_probe(struct idxd_device *idxd)
idxd_device_init_reset(idxd);
dev_dbg(dev, "IDXD reset complete\n");
if (IS_ENABLED(CONFIG_INTEL_IDXD_SVM)) {
if (IS_ENABLED(CONFIG_INTEL_IDXD_SVM) && sva) {
rc = idxd_enable_system_pasid(idxd);
if (rc < 0)
dev_warn(dev, "Failed to enable PASID. No SVA support: %d\n", rc);
else
set_bit(IDXD_FLAG_PASID_ENABLED, &idxd->flags);
} else if (!sva) {
dev_warn(dev, "User forced SVA off via module param.\n");
}
idxd_read_caps(idxd);