This adds create/remove window ioctls to create and remove DMA windows. sPAPR defines a Dynamic DMA windows capability which allows para-virtualized guests to create additional DMA windows on a PCI bus. The existing linux kernels use this new window to map the entire guest memory and switch to the direct DMA operations saving time on map/unmap requests which would normally happen in a big amounts.
This adds 2 ioctl handlers - VFIO_IOMMU_SPAPR_TCE_CREATE and VFIO_IOMMU_SPAPR_TCE_REMOVE - to create and remove windows. Up to 2 windows are supported now by the hardware and by this driver. This changes VFIO_IOMMU_SPAPR_TCE_GET_INFO handler to return additional information such as a number of supported windows and maximum number levels of TCE tables. Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> --- Changes: v4: * moved code to tce_iommu_create_window()/tce_iommu_remove_window() helpers * added docs --- Documentation/vfio.txt | 6 ++ arch/powerpc/include/asm/iommu.h | 2 +- drivers/vfio/vfio_iommu_spapr_tce.c | 156 +++++++++++++++++++++++++++++++++++- include/uapi/linux/vfio.h | 24 +++++- 4 files changed, 185 insertions(+), 3 deletions(-) diff --git a/Documentation/vfio.txt b/Documentation/vfio.txt index 791e85c..11628f1 100644 --- a/Documentation/vfio.txt +++ b/Documentation/vfio.txt @@ -446,6 +446,12 @@ the memory block. The user space is not expected to call these often and the block descriptors are stored in a linked list in the kernel. +6) sPAPR specification allows guests to have an ddditional DMA window(s) on +a PCI bus with a variable page size. Two ioctls have been added to support +this: VFIO_IOMMU_SPAPR_TCE_CREATE and VFIO_IOMMU_SPAPR_TCE_REMOVE. +The platform has to support the functionality or error will be returned to +the userspace. + ------------------------------------------------------------------------------- [1] VFIO was originally an acronym for "Virtual Function I/O" in its diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h index 8393822..6f34b82 100644 --- a/arch/powerpc/include/asm/iommu.h +++ b/arch/powerpc/include/asm/iommu.h @@ -133,7 +133,7 @@ extern void iommu_free_table(struct iommu_table *tbl, const char *node_name); extern struct iommu_table *iommu_init_table(struct iommu_table * tbl, int nid); -#define POWERPC_IOMMU_MAX_TABLES 1 +#define POWERPC_IOMMU_MAX_TABLES 2 #define POWERPC_IOMMU_DEFAULT_LEVELS 1 diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c index ee91d51..d5de7c6 100644 --- a/drivers/vfio/vfio_iommu_spapr_tce.c +++ b/drivers/vfio/vfio_iommu_spapr_tce.c @@ -333,6 +333,20 @@ static struct iommu_table *spapr_tce_find_table( return ret; } +static int spapr_tce_find_free_table(struct tce_container *container) +{ + int i; + + for (i = 0; i < POWERPC_IOMMU_MAX_TABLES; ++i) { + struct iommu_table *tbl = &container->tables[i]; + + if (!tbl->it_size) + return i; + } + + return -1; +} + static int tce_iommu_enable(struct tce_container *container) { int ret = 0; @@ -620,11 +634,85 @@ static long tce_iommu_build(struct tce_container *container, return ret; } +static long tce_iommu_create_window(struct tce_container *container, + __u32 page_shift, __u32 window_shift, __u32 levels, + __u64 *start_addr) +{ + struct powerpc_iommu *iommu; + struct tce_iommu_group *tcegrp; + int num; + long ret; + + num = spapr_tce_find_free_table(container); + if (num < 0) + return -ENOSYS; + + tcegrp = list_first_entry(&container->group_list, + struct tce_iommu_group, next); + iommu = iommu_group_get_iommudata(tcegrp->grp); + + ret = iommu->ops->create_table(iommu, num, + page_shift, window_shift, levels, + &container->tables[num]); + if (ret) + return ret; + + list_for_each_entry(tcegrp, &container->group_list, next) { + struct powerpc_iommu *iommutmp = + iommu_group_get_iommudata(tcegrp->grp); + + if (WARN_ON_ONCE(iommutmp->ops != iommu->ops)) + return -EFAULT; + + ret = iommu->ops->set_window(iommutmp, num, + &container->tables[num]); + if (ret) + return ret; + } + + *start_addr = container->tables[num].it_offset << + container->tables[num].it_page_shift; + + return 0; +} + +static long tce_iommu_remove_window(struct tce_container *container, + __u64 start_addr) +{ + struct powerpc_iommu *iommu = NULL; + struct iommu_table *tbl; + struct tce_iommu_group *tcegrp; + int num; + + tbl = spapr_tce_find_table(container, start_addr); + if (!tbl) + return -EINVAL; + + /* Detach groups from IOMMUs */ + num = tbl - container->tables; + list_for_each_entry(tcegrp, &container->group_list, next) { + iommu = iommu_group_get_iommudata(tcegrp->grp); + if (container->tables[num].it_size) + iommu->ops->unset_window(iommu, num); + } + + /* Free table */ + tcegrp = list_first_entry(&container->group_list, + struct tce_iommu_group, next); + iommu = iommu_group_get_iommudata(tcegrp->grp); + + tce_iommu_clear(container, tbl, + tbl->it_offset, tbl->it_size); + iommu->ops->free_table(tbl); + + return 0; +} + static long tce_iommu_ioctl(void *iommu_data, unsigned int cmd, unsigned long arg) { struct tce_container *container = iommu_data; - unsigned long minsz; + unsigned long minsz, ddwsz; long ret; switch (cmd) { @@ -666,6 +754,15 @@ static long tce_iommu_ioctl(void *iommu_data, info.dma32_window_start = iommu->tce32_start; info.dma32_window_size = iommu->tce32_size; + info.windows_supported = iommu->windows_supported; + info.levels = iommu->levels; + info.flags = iommu->flags; + + ddwsz = offsetofend(struct vfio_iommu_spapr_tce_info, + levels); + + if (info.argsz == ddwsz) + minsz = ddwsz; if (copy_to_user((void __user *)arg, &info, minsz)) return -EFAULT; @@ -828,6 +925,63 @@ static long tce_iommu_ioctl(void *iommu_data, return ret; } + case VFIO_IOMMU_SPAPR_TCE_CREATE: { + struct vfio_iommu_spapr_tce_create create; + + if (!tce_preregistered(container)) + return -EPERM; + + minsz = offsetofend(struct vfio_iommu_spapr_tce_create, + start_addr); + + if (copy_from_user(&create, (void __user *)arg, minsz)) + return -EFAULT; + + if (create.argsz < minsz) + return -EINVAL; + + if (create.flags) + return -EINVAL; + + mutex_lock(&container->lock); + + ret = tce_iommu_create_window(container, create.page_shift, + create.window_shift, create.levels, + &create.start_addr); + + if (!ret && copy_to_user((void __user *)arg, &create, minsz)) + return -EFAULT; + + mutex_unlock(&container->lock); + + return ret; + } + case VFIO_IOMMU_SPAPR_TCE_REMOVE: { + struct vfio_iommu_spapr_tce_remove remove; + + if (!tce_preregistered(container)) + return -EPERM; + + minsz = offsetofend(struct vfio_iommu_spapr_tce_remove, + start_addr); + + if (copy_from_user(&remove, (void __user *)arg, minsz)) + return -EFAULT; + + if (remove.argsz < minsz) + return -EINVAL; + + if (remove.flags) + return -EINVAL; + + mutex_lock(&container->lock); + + ret = tce_iommu_remove_window(container, remove.start_addr); + + mutex_unlock(&container->lock); + + return ret; + } } return -ENOTTY; diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 0f55c08..0f4b219 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -454,9 +454,11 @@ struct vfio_iommu_type1_dma_unmap { */ struct vfio_iommu_spapr_tce_info { __u32 argsz; - __u32 flags; /* reserved for future use */ + __u32 flags; __u32 dma32_window_start; /* 32 bit window start (bytes) */ __u32 dma32_window_size; /* 32 bit window size (bytes) */ + __u32 windows_supported; + __u32 levels; }; #define VFIO_IOMMU_SPAPR_TCE_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12) @@ -517,6 +519,26 @@ struct vfio_iommu_spapr_register_memory { */ #define VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY _IO(VFIO_TYPE, VFIO_BASE + 18) +struct vfio_iommu_spapr_tce_create { + __u32 argsz; + __u32 flags; + /* in */ + __u32 page_shift; + __u32 window_shift; + __u32 levels; + /* out */ + __u64 start_addr; +}; +#define VFIO_IOMMU_SPAPR_TCE_CREATE _IO(VFIO_TYPE, VFIO_BASE + 19) + +struct vfio_iommu_spapr_tce_remove { + __u32 argsz; + __u32 flags; + /* in */ + __u64 start_addr; +}; +#define VFIO_IOMMU_SPAPR_TCE_REMOVE _IO(VFIO_TYPE, VFIO_BASE + 20) + /* ***************************************************************** */ #endif /* _UAPIVFIO_H */ -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/