Messages in this thread | | | Subject | Re: [PATCH] vdpa_sim: use iova module to allocate IOVA addresses | From | Jason Wang <> | Date | Wed, 23 Dec 2020 11:43:40 +0800 |
| |
On 2020/12/23 上午1:45, Stefano Garzarella wrote: > The identical mapping used until now created issues when mapping > different virtual pages with the same physical address. > To solve this issue, we can use the iova module, to handle the IOVA > allocation. > For semplicity we use an IOVA allocator with byte granularity.
Should be simplicity, so did one comment below.
> > We add two new functions, vdpasim_map_range() and vdpasim_unmap_range(), > to handle the IOVA allocation and the registration into the IOMMU/IOTLB. > These functions are used by dma_map_ops callbacks. > > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Few nits, but:
Acked-by: Jason Wang <jasowang@redhat.com>
> --- > drivers/vdpa/vdpa_sim/vdpa_sim.h | 2 + > drivers/vdpa/vdpa_sim/vdpa_sim.c | 108 +++++++++++++++++++------------ > drivers/vdpa/Kconfig | 1 + > 3 files changed, 69 insertions(+), 42 deletions(-) > > diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h > index b02142293d5b..6efe205e583e 100644 > --- a/drivers/vdpa/vdpa_sim/vdpa_sim.h > +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h > @@ -6,6 +6,7 @@ > #ifndef _VDPA_SIM_H > #define _VDPA_SIM_H > > +#include <linux/iova.h> > #include <linux/vringh.h> > #include <linux/vdpa.h> > #include <linux/virtio_byteorder.h> > @@ -55,6 +56,7 @@ struct vdpasim { > /* virtio config according to device type */ > void *config; > struct vhost_iotlb *iommu; > + struct iova_domain iova; > void *buffer; > u32 status; > u32 generation; > diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c > index b3fcc67bfdf0..341b9daf2ea4 100644 > --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c > +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c > @@ -17,6 +17,7 @@ > #include <linux/vringh.h> > #include <linux/vdpa.h> > #include <linux/vhost_iotlb.h> > +#include <linux/iova.h> > > #include "vdpa_sim.h" > > @@ -128,30 +129,57 @@ static int dir_to_perm(enum dma_data_direction dir) > return perm; > } > > +static dma_addr_t vdpasim_map_range(struct vdpasim *vdpasim, phys_addr_t paddr, > + size_t size, unsigned int perm) > +{ > + struct iova *iova; > + dma_addr_t dma_addr; > + int ret; > + > + /* We set the limit_pfn to the maximum (~0UL - 1) */ > + iova = alloc_iova(&vdpasim->iova, size, ~0UL - 1, true);
Let's use ULONG_MAX?
> + if (!iova) > + return DMA_MAPPING_ERROR; > + > + dma_addr = iova_dma_addr(&vdpasim->iova, iova); > + > + spin_lock(&vdpasim->iommu_lock); > + ret = vhost_iotlb_add_range(vdpasim->iommu, (u64)dma_addr, > + (u64)dma_addr + size - 1, (u64)paddr, perm); > + spin_unlock(&vdpasim->iommu_lock); > + > + if (ret) { > + __free_iova(&vdpasim->iova, iova); > + return DMA_MAPPING_ERROR; > + } > + > + return dma_addr; > +} > + > +static void vdpasim_unmap_range(struct vdpasim *vdpasim, dma_addr_t dma_addr, > + size_t size) > +{ > + spin_lock(&vdpasim->iommu_lock); > + vhost_iotlb_del_range(vdpasim->iommu, (u64)dma_addr, > + (u64)dma_addr + size - 1); > + spin_unlock(&vdpasim->iommu_lock); > + > + free_iova(&vdpasim->iova, iova_pfn(&vdpasim->iova, dma_addr)); > +} > + > static dma_addr_t vdpasim_map_page(struct device *dev, struct page *page, > unsigned long offset, size_t size, > enum dma_data_direction dir, > unsigned long attrs) > { > struct vdpasim *vdpasim = dev_to_sim(dev); > - struct vhost_iotlb *iommu = vdpasim->iommu; > - u64 pa = (page_to_pfn(page) << PAGE_SHIFT) + offset; > - int ret, perm = dir_to_perm(dir); > + phys_addr_t paddr = page_to_phys(page) + offset; > + int perm = dir_to_perm(dir); > > if (perm < 0) > return DMA_MAPPING_ERROR; > > - /* For simplicity, use identical mapping to avoid e.g iova > - * allocator. > - */ > - spin_lock(&vdpasim->iommu_lock); > - ret = vhost_iotlb_add_range(iommu, pa, pa + size - 1, > - pa, dir_to_perm(dir)); > - spin_unlock(&vdpasim->iommu_lock); > - if (ret) > - return DMA_MAPPING_ERROR; > - > - return (dma_addr_t)(pa); > + return vdpasim_map_range(vdpasim, paddr, size, perm); > } > > static void vdpasim_unmap_page(struct device *dev, dma_addr_t dma_addr, > @@ -159,12 +187,8 @@ static void vdpasim_unmap_page(struct device *dev, dma_addr_t dma_addr, > unsigned long attrs) > { > struct vdpasim *vdpasim = dev_to_sim(dev); > - struct vhost_iotlb *iommu = vdpasim->iommu; > > - spin_lock(&vdpasim->iommu_lock); > - vhost_iotlb_del_range(iommu, (u64)dma_addr, > - (u64)dma_addr + size - 1); > - spin_unlock(&vdpasim->iommu_lock); > + vdpasim_unmap_range(vdpasim, dma_addr, size); > } > > static void *vdpasim_alloc_coherent(struct device *dev, size_t size, > @@ -172,27 +196,22 @@ static void *vdpasim_alloc_coherent(struct device *dev, size_t size, > unsigned long attrs) > { > struct vdpasim *vdpasim = dev_to_sim(dev); > - struct vhost_iotlb *iommu = vdpasim->iommu; > - void *addr = kmalloc(size, flag); > - int ret; > + phys_addr_t paddr; > + void *addr; > > - spin_lock(&vdpasim->iommu_lock); > + addr = kmalloc(size, flag); > if (!addr) { > *dma_addr = DMA_MAPPING_ERROR; > - } else { > - u64 pa = virt_to_phys(addr); > - > - ret = vhost_iotlb_add_range(iommu, (u64)pa, > - (u64)pa + size - 1, > - pa, VHOST_MAP_RW); > - if (ret) { > - *dma_addr = DMA_MAPPING_ERROR; > - kfree(addr); > - addr = NULL; > - } else > - *dma_addr = (dma_addr_t)pa; > + return NULL; > + } > + > + paddr = virt_to_phys(addr); > + > + *dma_addr = vdpasim_map_range(vdpasim, paddr, size, VHOST_MAP_RW); > + if (*dma_addr == DMA_MAPPING_ERROR) { > + kfree(addr); > + return NULL; > } > - spin_unlock(&vdpasim->iommu_lock); > > return addr; > } > @@ -202,14 +221,10 @@ static void vdpasim_free_coherent(struct device *dev, size_t size, > unsigned long attrs) > { > struct vdpasim *vdpasim = dev_to_sim(dev); > - struct vhost_iotlb *iommu = vdpasim->iommu; > > - spin_lock(&vdpasim->iommu_lock); > - vhost_iotlb_del_range(iommu, (u64)dma_addr, > - (u64)dma_addr + size - 1); > - spin_unlock(&vdpasim->iommu_lock); > + vdpasim_unmap_range(vdpasim, dma_addr, size); > > - kfree(phys_to_virt((uintptr_t)dma_addr)); > + kfree(vaddr); > } > > static const struct dma_map_ops vdpasim_dma_ops = { > @@ -270,6 +285,13 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr) > for (i = 0; i < dev_attr->nvqs; i++) > vringh_set_iotlb(&vdpasim->vqs[i].vring, vdpasim->iommu); > > + ret = iova_cache_get(); > + if (ret) > + goto err_iommu; > + > + /* For semplicity we use an IOVA allocator with byte granularity */
Should be simplicity.
Thanks
> + init_iova_domain(&vdpasim->iova, 1, 0); > + > vdpasim->vdpa.dma_dev = dev; > > return vdpasim; > @@ -540,6 +562,8 @@ static void vdpasim_free(struct vdpa_device *vdpa) > struct vdpasim *vdpasim = vdpa_to_sim(vdpa); > > cancel_work_sync(&vdpasim->work); > + put_iova_domain(&vdpasim->iova); > + iova_cache_put(); > kvfree(vdpasim->buffer); > if (vdpasim->iommu) > vhost_iotlb_free(vdpasim->iommu); > diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig > index 92a6396f8a73..8965e3717231 100644 > --- a/drivers/vdpa/Kconfig > +++ b/drivers/vdpa/Kconfig > @@ -13,6 +13,7 @@ config VDPA_SIM > depends on RUNTIME_TESTING_MENU && HAS_DMA > select DMA_OPS > select VHOST_RING > + select IOMMU_IOVA > help > Enable this module to support vDPA device simulators. These devices > are used for testing, prototyping and development of vDPA.
| |