Commit 03d939c7 authored by Dave Jiang's avatar Dave Jiang Committed by Vinod Koul
Browse files

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: default avatarDave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/161134110457.4005461.13171197785259115852.stgit@djiang5-desk3.ch.intel.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 9f3c14d4

Documentation/admin-guide/kernel-parameters.txt

+6 −0
Original line number Diff line number Diff line
@@ -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

drivers/dma/idxd/init.c

+7 −1
Original line number Diff line number Diff line
@@ -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);