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vfio: Provide module option to disable vfio_iommu_type1 hugepage support

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Add a module option to vfio_iommu_type1 to disable IOMMU hugepage
support.  This causes iommu_map to only be called with single page
mappings, disabling the IOMMU driver's ability to use hugepages.
This option can be enabled by loading vfio_iommu_type1 with
disable_hugepages=1 or dynamically through sysfs.  If enabled
dynamically, only new mappings are restricted.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Alex Williamson 2013-06-21 09:38:11 -06:00
parent 166fd7d94a
commit 5c6c2b21ec
1 changed files with 11 additions and 0 deletions
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11
drivers/vfio/vfio_iommu_type1.c
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@ -48,6 +48,12 @@ module_param_named(allow_unsafe_interrupts,
MODULE_PARM_DESC(allow_unsafe_interrupts,
"Enable VFIO IOMMU support for on platforms without interrupt remapping support.");
static bool disable_hugepages;
module_param_named(disable_hugepages,
disable_hugepages, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(disable_hugepages,
"Disable VFIO IOMMU support for IOMMU hugepages.");
struct vfio_iommu {
struct iommu_domain *domain;
struct mutex lock;
@ -270,6 +276,11 @@ static long vfio_pin_pages(unsigned long vaddr, long npage,
return -ENOMEM;
}
if (unlikely(disable_hugepages)) {
vfio_lock_acct(1);
return 1;
}
/* Lock all the consecutive pages from pfn_base */
for (i = 1, vaddr += PAGE_SIZE; i < npage; i++, vaddr += PAGE_SIZE) {
unsigned long pfn = 0;