On Tue, May 28, 2013 at 10:27:52AM -0600, Alex Williamson wrote:
> 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.william...@redhat.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
> ---
>
> As suggested by Konrad. This is cleaner to add as a follow-on
>
> drivers/vfio/vfio_iommu_type1.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 6654a7e..8a2be4e 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -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;
>
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