[PATCH v1 2/8] vfio/type1: Add vfio_iommu_type1 parameter for quota tuning

Liu, Yi L
2020-03-22T12:26:52Z

From: Liu Yi L <yi.l.liu@intel.com>

This patch adds a module option to make the PASID quota tunable by
administrator.

TODO: needs to think more on how to make the tuning to be per-process.

Previous discussions:
https://patchwork.kernel.org/patch/11209429/

Cc: Kevin Tian <kevin.tian@intel.com>
CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
---
drivers/vfio/vfio.c | 8 +++++++-
drivers/vfio/vfio_iommu_type1.c | 7 ++++++-
include/linux/vfio.h | 3 ++-
3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index d13b483..020a792 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -2217,13 +2217,19 @@ struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task)
}
EXPORT_SYMBOL_GPL(vfio_mm_get_from_task);

-int vfio_mm_pasid_alloc(struct vfio_mm *vmm, int min, int max)
+int vfio_mm_pasid_alloc(struct vfio_mm *vmm, int quota, int min, int max)
{
ioasid_t pasid;
int ret = -ENOSPC;

mutex_lock(&vmm->pasid_lock);

+ /* update quota as it is tunable by admin */
+ if (vmm->pasid_quota != quota) {
+ vmm->pasid_quota = quota;
+ ioasid_adjust_set(vmm->ioasid_sid, quota);
+ }
+
pasid = ioasid_alloc(vmm->ioasid_sid, min, max, NULL);
if (pasid == INVALID_IOASID) {
ret = -ENOSPC;
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 331ceee..e40afc0 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -60,6 +60,11 @@ module_param_named(dma_entry_limit, dma_entry_limit, uint, 0644);
MODULE_PARM_DESC(dma_entry_limit,
"Maximum number of user DMA mappings per container (65535).");

+static int pasid_quota = VFIO_DEFAULT_PASID_QUOTA;
+module_param_named(pasid_quota, pasid_quota, uint, 0644);
+MODULE_PARM_DESC(pasid_quota,
+ "Quota of user owned PASIDs per vfio-based application (1000).");
+
struct vfio_iommu {
struct list_head domain_list;
struct list_head iova_list;
@@ -2200,7 +2205,7 @@ static int vfio_iommu_type1_pasid_alloc(struct vfio_iommu *iommu,
goto out_unlock;
}
if (vmm)
- ret = vfio_mm_pasid_alloc(vmm, min, max);
+ ret = vfio_mm_pasid_alloc(vmm, pasid_quota, min, max);
else
ret = -EINVAL;
out_unlock:
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 75f9f7f1..af2ef78 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -106,7 +106,8 @@ struct vfio_mm {

extern struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task);
extern void vfio_mm_put(struct vfio_mm *vmm);
-extern int vfio_mm_pasid_alloc(struct vfio_mm *vmm, int min, int max);
+extern int vfio_mm_pasid_alloc(struct vfio_mm *vmm,
+ int quota, int min, int max);
extern int vfio_mm_pasid_free(struct vfio_mm *vmm, ioasid_t pasid);

/*
--
2.7.4