Re: [RFT][PATCH v2 4/9] vfio: Pass in starting IOVA to vfio_pin/unpin_pages API

Kirti Wankhede
2022-07-06T17:39:29Z

Reviewed by: Kirti Wankhede <kwankhede@nvidia.com>

On 7/6/2022 11:57 AM, Nicolin Chen wrote:
> The vfio_pin/unpin_pages() so far accepted arrays of PFNs of user IOVA.
> Among all three callers, there was only one caller possibly passing in
> a non-contiguous PFN list, which is now ensured to have contiguous PFN
> inputs too.
>
> Pass in the starting address with "iova" alone to simplify things, so
> callers no longer need to maintain a PFN list or to pin/unpin one page
> at a time. This also allows VFIO to use more efficient implementations
> of pin/unpin_pages.
>
> For now, also update vfio_iommu_type1 to fit this new parameter too,
> while keeping its input intact (being user_iova) since we don't want
> to spend too much effort swapping its parameters and local variables
> at that level.
>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
> .../driver-api/vfio-mediated-device.rst | 4 +--
> drivers/gpu/drm/i915/gvt/kvmgt.c | 24 ++++++-----------
> drivers/s390/cio/vfio_ccw_cp.c | 4 +--
> drivers/s390/crypto/vfio_ap_ops.c | 9 +++----
> drivers/vfio/vfio.c | 27 +++++++++----------
> drivers/vfio/vfio.h | 4 +--
> drivers/vfio/vfio_iommu_type1.c | 17 ++++++------
> include/linux/vfio.h | 5 ++--
> 8 files changed, 40 insertions(+), 54 deletions(-)
>
> diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
> index b0fdf76b339a..ea32a0f13ddb 100644
> --- a/Documentation/driver-api/vfio-mediated-device.rst
> +++ b/Documentation/driver-api/vfio-mediated-device.rst
> @@ -262,10 +262,10 @@ Translation APIs for Mediated Devices
> The following APIs are provided for translating user pfn to host pfn in a VFIO
> driver::
>
> - int vfio_pin_pages(struct vfio_device *device, unsigned long *user_pfn,
> + int vfio_pin_pages(struct vfio_device *device, dma_addr_t iova,
> int npage, int prot, unsigned long *phys_pfn);
>
> - void vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn,
> + void vfio_unpin_pages(struct vfio_device *device, dma_addr_t iova,
> int npage);
>
> These functions call back into the back-end IOMMU module by using the pin_pages
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 8c67c9aba82d..ea6041fa48ac 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -231,16 +231,8 @@ static void intel_gvt_cleanup_vgpu_type_groups(struct intel_gvt *gvt)
> static void gvt_unpin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn,
> unsigned long size)
> {
> - int total_pages;
> - int npage;
> -
> - total_pages = roundup(size, PAGE_SIZE) / PAGE_SIZE;
> -
> - for (npage = 0; npage < total_pages; npage++) {
> - unsigned long cur_gfn = gfn + npage;
> -
> - vfio_unpin_pages(&vgpu->vfio_device, &cur_gfn, 1);
> - }
> + vfio_unpin_pages(&vgpu->vfio_device, gfn << PAGE_SHIFT,
> + roundup(size, PAGE_SIZE) / PAGE_SIZE);
> }
>
> /* Pin a normal or compound guest page for dma. */
> @@ -258,14 +250,14 @@ static int gvt_pin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn,
> * on stack to hold pfns.
> */
> for (npage = 0; npage < total_pages; npage++) {
> - unsigned long cur_gfn = gfn + npage;
> + dma_addr_t cur_iova = (gfn + npage) << PAGE_SHIFT;
> unsigned long pfn;
>
> - ret = vfio_pin_pages(&vgpu->vfio_device, &cur_gfn, 1,
> + ret = vfio_pin_pages(&vgpu->vfio_device, cur_iova, 1,
> IOMMU_READ | IOMMU_WRITE, &pfn);
> if (ret != 1) {
> - gvt_vgpu_err("vfio_pin_pages failed for gfn 0x%lx, ret %d\n",
> - cur_gfn, ret);
> + gvt_vgpu_err("vfio_pin_pages failed for iova %pad, ret %d\n",
> + &cur_iova, ret);
> goto err;
> }
>
> @@ -309,7 +301,7 @@ static int gvt_dma_map_page(struct intel_vgpu *vgpu, unsigned long gfn,
> if (dma_mapping_error(dev, *dma_addr)) {
> gvt_vgpu_err("DMA mapping failed for pfn 0x%lx, ret %d\n",
> page_to_pfn(page), ret);
> - gvt_unpin_guest_page(vgpu, gfn, size);
> + gvt_unpin_guest_page(vgpu, gfn << PAGE_SHIFT, size);
> return -ENOMEM;
> }
>
> @@ -322,7 +314,7 @@ static void gvt_dma_unmap_page(struct intel_vgpu *vgpu, unsigned long gfn,
> struct device *dev = vgpu->gvt->gt->i915->drm.dev;
>
> dma_unmap_page(dev, dma_addr, size, DMA_BIDIRECTIONAL);
> - gvt_unpin_guest_page(vgpu, gfn, size);
> + gvt_unpin_guest_page(vgpu, gfn << PAGE_SHIFT, size);
> }
>
> static struct gvt_dma *__gvt_cache_find_dma_addr(struct intel_vgpu *vgpu,
> diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
> index 3b94863ad24e..a739262f988d 100644
> --- a/drivers/s390/cio/vfio_ccw_cp.c
> +++ b/drivers/s390/cio/vfio_ccw_cp.c
> @@ -114,7 +114,7 @@ static void pfn_array_unpin(struct pfn_array *pa,
> continue;
> }
>
> - vfio_unpin_pages(vdev, first, npage);
> + vfio_unpin_pages(vdev, *first << PAGE_SHIFT, npage);
> unpinned += npage;
> npage = 1;
> }
> @@ -146,7 +146,7 @@ static int pfn_array_pin(struct pfn_array *pa, struct vfio_device *vdev)
> continue;
> }
>
> - ret = vfio_pin_pages(vdev, first, npage,
> + ret = vfio_pin_pages(vdev, *first << PAGE_SHIFT, npage,
> IOMMU_READ | IOMMU_WRITE,
> &pa->pa_pfn[pinned]);
> if (ret < 0) {
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index bb869b28cebd..8a2018ab3cf0 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -124,7 +124,7 @@ static void vfio_ap_free_aqic_resources(struct vfio_ap_queue *q)
> q->saved_isc = VFIO_AP_ISC_INVALID;
> }
> if (q->saved_pfn && !WARN_ON(!q->matrix_mdev)) {
> - vfio_unpin_pages(&q->matrix_mdev->vdev, &q->saved_pfn, 1);
> + vfio_unpin_pages(&q->matrix_mdev->vdev, q->saved_pfn << PAGE_SHIFT, 1);
> q->saved_pfn = 0;
> }
> }
> @@ -258,7 +258,7 @@ static struct ap_queue_status vfio_ap_irq_enable(struct vfio_ap_queue *q,
> return status;
> }
>
> - ret = vfio_pin_pages(&q->matrix_mdev->vdev, &g_pfn, 1,
> + ret = vfio_pin_pages(&q->matrix_mdev->vdev, g_pfn << PAGE_SHIFT, 1,
> IOMMU_READ | IOMMU_WRITE, &h_pfn);
> switch (ret) {
> case 1:
> @@ -301,7 +301,7 @@ static struct ap_queue_status vfio_ap_irq_enable(struct vfio_ap_queue *q,
> break;
> case AP_RESPONSE_OTHERWISE_CHANGED:
> /* We could not modify IRQ setings: clear new configuration */
> - vfio_unpin_pages(&q->matrix_mdev->vdev, &g_pfn, 1);
> + vfio_unpin_pages(&q->matrix_mdev->vdev, g_pfn << PAGE_SHIFT, 1);
> kvm_s390_gisc_unregister(kvm, isc);
> break;
> default:
> @@ -1248,9 +1248,8 @@ static int vfio_ap_mdev_iommu_notifier(struct notifier_block *nb,
>
> if (action == VFIO_IOMMU_NOTIFY_DMA_UNMAP) {
> struct vfio_iommu_type1_dma_unmap *unmap = data;
> - unsigned long g_pfn = unmap->iova >> PAGE_SHIFT;
>
> - vfio_unpin_pages(&matrix_mdev->vdev, &g_pfn, 1);
> + vfio_unpin_pages(&matrix_mdev->vdev, unmap->iova, 1);
> return NOTIFY_OK;
> }
>
> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
> index 01f45ec70a3d..813b517c973e 100644
> --- a/drivers/vfio/vfio.c
> +++ b/drivers/vfio/vfio.c
> @@ -1910,17 +1910,17 @@ int vfio_set_irqs_validate_and_prepare(struct vfio_irq_set *hdr, int num_irqs,
> EXPORT_SYMBOL(vfio_set_irqs_validate_and_prepare);
>
> /*
> - * Pin a set of guest PFNs and return their associated host PFNs for local
> + * Pin contiguous guest pages and return their associated host pages for local
> * domain only.
> * @device [in] : device
> - * @user_pfn [in]: array of user/guest PFNs to be pinned.
> - * @npage [in] : count of elements in user_pfn array. This count should not
> + * @iova [in] : starting IOVA of user/guest pages to be pinned.
> + * @npage [in] : count of pages to be pinned. 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_pin_pages(struct vfio_device *device, unsigned long *user_pfn,
> +int vfio_pin_pages(struct vfio_device *device, dma_addr_t iova,
> int npage, int prot, unsigned long *phys_pfn)
> {
> struct vfio_container *container;
> @@ -1928,8 +1928,7 @@ int vfio_pin_pages(struct vfio_device *device, unsigned long *user_pfn,
> struct vfio_iommu_driver *driver;
> int ret;
>
> - if (!user_pfn || !phys_pfn || !npage ||
> - !vfio_assert_device_open(device))
> + if (!phys_pfn || !npage || !vfio_assert_device_open(device))
> return -EINVAL;
>
> if (npage > VFIO_PIN_PAGES_MAX_ENTRIES)
> @@ -1943,7 +1942,7 @@ int vfio_pin_pages(struct vfio_device *device, unsigned long *user_pfn,
> driver = container->iommu_driver;
> if (likely(driver && driver->ops->pin_pages))
> ret = driver->ops->pin_pages(container->iommu_data,
> - group->iommu_group, user_pfn,
> + group->iommu_group, iova,
> npage, prot, phys_pfn);
> else
> ret = -ENOTTY;
> @@ -1953,20 +1952,18 @@ int vfio_pin_pages(struct vfio_device *device, unsigned long *user_pfn,
> EXPORT_SYMBOL(vfio_pin_pages);
>
> /*
> - * Unpin set of host PFNs for local domain only.
> + * Unpin contiguous host pages for local domain only.
> * @device [in] : device
> - * @user_pfn [in]: array of user/guest PFNs to be unpinned. Number of user/guest
> - * PFNs should not be greater than VFIO_PIN_PAGES_MAX_ENTRIES.
> - * @npage [in] : count of elements in user_pfn array. This count should not
> + * @iova [in] : starting address of user/guest pages to be unpinned.
> + * @npage [in] : count of pages to be unpinned. This count should not
> * be greater than VFIO_PIN_PAGES_MAX_ENTRIES.
> */
> -void vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn,
> - int npage)
> +void vfio_unpin_pages(struct vfio_device *device, dma_addr_t iova, int npage)
> {
> struct vfio_container *container;
> struct vfio_iommu_driver *driver;
>
> - if (WARN_ON_ONCE(!user_pfn || !npage || !vfio_assert_device_open(device)))
> + if (WARN_ON_ONCE(!npage || !vfio_assert_device_open(device)))
> return;
>
> if (WARN_ON_ONCE(npage > VFIO_PIN_PAGES_MAX_ENTRIES))
> @@ -1979,7 +1976,7 @@ void vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn,
> if (WARN_ON_ONCE(unlikely(!driver || !driver->ops->unpin_pages)))
> return;
>
> - driver->ops->unpin_pages(container->iommu_data, user_pfn, npage);
> + driver->ops->unpin_pages(container->iommu_data, iova, npage);
> }
> EXPORT_SYMBOL(vfio_unpin_pages);
>
> diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
> index bef4edf58138..dbcd0e8c031b 100644
> --- a/drivers/vfio/vfio.h
> +++ b/drivers/vfio/vfio.h
> @@ -50,11 +50,11 @@ struct vfio_iommu_driver_ops {
> struct iommu_group *group);
> int (*pin_pages)(void *iommu_data,
> struct iommu_group *group,
> - unsigned long *user_pfn,
> + dma_addr_t user_iova,
> int npage, int prot,
> unsigned long *phys_pfn);
> void (*unpin_pages)(void *iommu_data,
> - unsigned long *user_pfn, int npage);
> + dma_addr_t user_iova, int npage);
> int (*register_notifier)(void *iommu_data,
> unsigned long *events,
> struct notifier_block *nb);
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 08613edaf722..f10d0c4b1f26 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -828,7 +828,7 @@ static int vfio_unpin_page_external(struct vfio_dma *dma, dma_addr_t iova,
>
> static int vfio_iommu_type1_pin_pages(void *iommu_data,
> struct iommu_group *iommu_group,
> - unsigned long *user_pfn,
> + dma_addr_t user_iova,
> int npage, int prot,
> unsigned long *phys_pfn)
> {
> @@ -840,7 +840,7 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data,
> bool do_accounting;
> dma_addr_t iova;
>
> - if (!iommu || !user_pfn || !phys_pfn)
> + if (!iommu || !phys_pfn)
> return -EINVAL;
>
> /* Supported for v2 version only */
> @@ -856,7 +856,7 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data,
> again:
> if (iommu->vaddr_invalid_count) {
> for (i = 0; i < npage; i++) {
> - iova = user_pfn[i] << PAGE_SHIFT;
> + iova = user_iova + PAGE_SIZE * i;
> ret = vfio_find_dma_valid(iommu, iova, PAGE_SIZE, &dma);
> if (ret < 0)
> goto pin_done;
> @@ -881,7 +881,7 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data,
> for (i = 0; i < npage; i++) {
> struct vfio_pfn *vpfn;
>
> - iova = user_pfn[i] << PAGE_SHIFT;
> + iova = user_iova + PAGE_SIZE * i;
> dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
> if (!dma) {
> ret = -EINVAL;
> @@ -938,7 +938,7 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data,
> for (j = 0; j < i; j++) {
> dma_addr_t iova;
>
> - iova = user_pfn[j] << PAGE_SHIFT;
> + iova = user_iova + PAGE_SIZE * j;
> dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
> vfio_unpin_page_external(dma, iova, do_accounting);
> phys_pfn[j] = 0;
> @@ -949,13 +949,13 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data,
> }
>
> static void vfio_iommu_type1_unpin_pages(void *iommu_data,
> - unsigned long *user_pfn, int npage)
> + dma_addr_t user_iova, int npage)
> {
> struct vfio_iommu *iommu = iommu_data;
> bool do_accounting;
> int i;
>
> - if (WARN_ON_ONCE(!iommu || !user_pfn || npage <= 0))
> + if (WARN_ON_ONCE(!iommu || npage <= 0))
> return;
>
> /* Supported for v2 version only */
> @@ -966,10 +966,9 @@ static void vfio_iommu_type1_unpin_pages(void *iommu_data,
>
> do_accounting = list_empty(&iommu->domain_list);
> for (i = 0; i < npage; i++) {
> + dma_addr_t iova = user_iova + PAGE_SIZE * i;
> struct vfio_dma *dma;
> - dma_addr_t iova;
>
> - iova = user_pfn[i] << PAGE_SHIFT;
> dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
> if (!dma)
> break;
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index d0844ecdc961..c3e441c0bf4b 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -147,10 +147,9 @@ bool vfio_file_has_dev(struct file *file, struct vfio_device *device);
>
> #define VFIO_PIN_PAGES_MAX_ENTRIES (PAGE_SIZE/sizeof(unsigned long))
>
> -int vfio_pin_pages(struct vfio_device *device, unsigned long *user_pfn,
> +int vfio_pin_pages(struct vfio_device *device, dma_addr_t iova,
> int npage, int prot, unsigned long *phys_pfn);
> -void vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn,
> - int npage);
> +void vfio_unpin_pages(struct vfio_device *device, dma_addr_t iova, int npage);
> int vfio_dma_rw(struct vfio_device *device, dma_addr_t user_iova,
> void *data, size_t len, bool write);
>