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author | Yan Zhao <yan.y.zhao@intel.com> | 2020-03-24 09:27:57 -0600 |
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committer | Alex Williamson <alex.williamson@redhat.com> | 2020-03-24 09:27:57 -0600 |
commit | 40280cf7e8ca7d31bb0a9d626f36f458fec32815 (patch) | |
tree | cc55f06e79d3e7d99ae50e9f5a27b58b36153599 | |
parent | 8d46c0cca5f4dc0538173d62cd36b1119b5105bc (diff) | |
download | linux-stable-40280cf7e8ca7d31bb0a9d626f36f458fec32815.tar.gz linux-stable-40280cf7e8ca7d31bb0a9d626f36f458fec32815.tar.bz2 linux-stable-40280cf7e8ca7d31bb0a9d626f36f458fec32815.zip |
vfio: avoid inefficient operations on VFIO group in vfio_pin/unpin_pages
vfio_group_pin_pages() and vfio_group_unpin_pages() are introduced to
avoid inefficient search/check/ref/deref opertions associated with VFIO
group as those in each calling into vfio_pin_pages() and
vfio_unpin_pages().
VFIO group is taken as arg directly. The callers combine
search/check/ref/deref operations associated with VFIO group by calling
vfio_group_get_external_user()/vfio_group_get_external_user_from_dev()
beforehand, and vfio_group_put_external_user() afterwards.
Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
-rw-r--r-- | drivers/vfio/vfio.c | 91 | ||||
-rw-r--r-- | include/linux/vfio.h | 6 |
2 files changed, 97 insertions, 0 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 6997f711b925..210fcf426643 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -1999,6 +1999,97 @@ err_unpin_pages: } EXPORT_SYMBOL(vfio_unpin_pages); +/* + * Pin a set of guest IOVA PFNs and return their associated host PFNs for a + * VFIO group. + * + * The caller needs to call vfio_group_get_external_user() or + * vfio_group_get_external_user_from_dev() prior to calling this interface, + * so as to prevent the VFIO group from disposal in the middle of the call. + * But it can keep the reference to the VFIO group for several calls into + * this interface. + * After finishing using of the VFIO group, the caller needs to release the + * VFIO group by calling vfio_group_put_external_user(). + * + * @group [in] : VFIO group + * @user_iova_pfn [in] : array of user/guest IOVA PFNs to be pinned. + * @npage [in] : count of elements in user_iova_pfn array. + * This count should not be greater + * VFIO_PIN_PAGES_MAX_ENTRIES. + * @prot [in] : protection flags + * @phys_pfn [out] : array of host PFNs + * Return error or number of pages pinned. + */ +int vfio_group_pin_pages(struct vfio_group *group, + unsigned long *user_iova_pfn, int npage, + int prot, unsigned long *phys_pfn) +{ + struct vfio_container *container; + struct vfio_iommu_driver *driver; + int ret; + + if (!group || !user_iova_pfn || !phys_pfn || !npage) + return -EINVAL; + + if (npage > VFIO_PIN_PAGES_MAX_ENTRIES) + return -E2BIG; + + container = group->container; + driver = container->iommu_driver; + if (likely(driver && driver->ops->pin_pages)) + ret = driver->ops->pin_pages(container->iommu_data, + user_iova_pfn, npage, + prot, phys_pfn); + else + ret = -ENOTTY; + + return ret; +} +EXPORT_SYMBOL(vfio_group_pin_pages); + +/* + * Unpin a set of guest IOVA PFNs for a VFIO group. + * + * The caller needs to call vfio_group_get_external_user() or + * vfio_group_get_external_user_from_dev() prior to calling this interface, + * so as to prevent the VFIO group from disposal in the middle of the call. + * But it can keep the reference to the VFIO group for several calls into + * this interface. + * After finishing using of the VFIO group, the caller needs to release the + * VFIO group by calling vfio_group_put_external_user(). + * + * @group [in] : vfio group + * @user_iova_pfn [in] : array of user/guest IOVA PFNs to be unpinned. + * @npage [in] : count of elements in user_iova_pfn array. + * This count should not be greater than + * VFIO_PIN_PAGES_MAX_ENTRIES. + * Return error or number of pages unpinned. + */ +int vfio_group_unpin_pages(struct vfio_group *group, + unsigned long *user_iova_pfn, int npage) +{ + struct vfio_container *container; + struct vfio_iommu_driver *driver; + int ret; + + if (!group || !user_iova_pfn || !npage) + return -EINVAL; + + if (npage > VFIO_PIN_PAGES_MAX_ENTRIES) + return -E2BIG; + + container = group->container; + driver = container->iommu_driver; + if (likely(driver && driver->ops->unpin_pages)) + ret = driver->ops->unpin_pages(container->iommu_data, + user_iova_pfn, npage); + else + ret = -ENOTTY; + + return ret; +} +EXPORT_SYMBOL(vfio_group_unpin_pages); + /* * This interface allows the CPUs to perform some sort of virtual DMA on diff --git a/include/linux/vfio.h b/include/linux/vfio.h index 34b2fdf4de6e..be2bd358b952 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -111,6 +111,12 @@ extern int vfio_pin_pages(struct device *dev, unsigned long *user_pfn, extern int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn, int npage); +extern int vfio_group_pin_pages(struct vfio_group *group, + unsigned long *user_iova_pfn, int npage, + int prot, unsigned long *phys_pfn); +extern int vfio_group_unpin_pages(struct vfio_group *group, + unsigned long *user_iova_pfn, int npage); + extern int vfio_dma_rw(struct vfio_group *group, dma_addr_t user_iova, void *data, size_t len, bool write); |