From: Jason Gunthorpe jgg@nvidia.com
iommufd has a model where the iommu_domain can be changed while the VFIO device is attached. In this case the MSI should continue to work. This corner case has not worked because the dma-iommu implementation of sw_msi is tied to a single domain.
Implement the sw_msi mapping directly and use a global per-fd table to associate assigned iova to the MSI pages. This allows the MSI pages to be loaded into a domain before it is attached ensuring that MSI is not disrupted.
Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Nicolin Chen nicolinc@nvidia.com --- drivers/iommu/iommufd/iommufd_private.h | 23 +++- drivers/iommu/iommufd/device.c | 174 +++++++++++++++++++----- drivers/iommu/iommufd/hw_pagetable.c | 3 + drivers/iommu/iommufd/main.c | 9 ++ 4 files changed, 175 insertions(+), 34 deletions(-)
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index 8e0e3ab64747..246297452a44 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -19,6 +19,22 @@ struct iommu_group; struct iommu_option; struct iommufd_device;
+struct iommufd_sw_msi_map { + struct list_head sw_msi_item; + phys_addr_t sw_msi_start; + phys_addr_t msi_addr; + unsigned int pgoff; + unsigned int id; +}; + +/* Bitmap of struct iommufd_sw_msi_map::id */ +struct iommufd_sw_msi_maps { + DECLARE_BITMAP(bitmap, 64); +}; + +int iommufd_sw_msi(struct iommu_domain *domain, struct msi_desc *desc, + phys_addr_t msi_addr); + struct iommufd_ctx { struct file *file; struct xarray objects; @@ -26,6 +42,10 @@ struct iommufd_ctx { wait_queue_head_t destroy_wait; struct rw_semaphore ioas_creation_lock;
+ struct mutex sw_msi_lock; + struct list_head sw_msi_list; + unsigned int sw_msi_id; + u8 account_mode; /* Compatibility with VFIO no iommu */ u8 no_iommu_mode; @@ -283,10 +303,10 @@ struct iommufd_hwpt_paging { struct iommufd_ioas *ioas; bool auto_domain : 1; bool enforce_cache_coherency : 1; - bool msi_cookie : 1; bool nest_parent : 1; /* Head at iommufd_ioas::hwpt_list */ struct list_head hwpt_item; + struct iommufd_sw_msi_maps present_sw_msi; };
struct iommufd_hwpt_nested { @@ -383,6 +403,7 @@ struct iommufd_group { struct iommu_group *group; struct iommufd_hw_pagetable *hwpt; struct list_head device_list; + struct iommufd_sw_msi_maps required_sw_msi; phys_addr_t sw_msi_start; };
diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c index 360ba3ed8545..e435ba13a8a5 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -5,6 +5,7 @@ #include <linux/iommufd.h> #include <linux/slab.h> #include <uapi/linux/iommufd.h> +#include <linux/msi.h>
#include "../iommu-priv.h" #include "io_pagetable.h" @@ -293,36 +294,152 @@ u32 iommufd_device_to_id(struct iommufd_device *idev) } EXPORT_SYMBOL_NS_GPL(iommufd_device_to_id, "IOMMUFD");
+/* + * Get a iommufd_sw_msi_map for the msi physical address requested by the irq + * layer. The mapping to IOVA is global to the iommufd file descriptor, every + * domain that is attached to a device using the same MSI parameters will use + * the same IOVA. + */ +static struct iommufd_sw_msi_map * +iommufd_sw_msi_get_map(struct iommufd_ctx *ictx, phys_addr_t msi_addr, + phys_addr_t sw_msi_start) +{ + struct iommufd_sw_msi_map *cur; + unsigned int max_pgoff = 0; + + lockdep_assert_held(&ictx->sw_msi_lock); + + list_for_each_entry(cur, &ictx->sw_msi_list, sw_msi_item) { + if (cur->sw_msi_start != sw_msi_start) + continue; + max_pgoff = max(max_pgoff, cur->pgoff + 1); + if (cur->msi_addr == msi_addr) + return cur; + } + + if (ictx->sw_msi_id >= + BITS_PER_BYTE * sizeof_field(struct iommufd_sw_msi_maps, bitmap)) + return ERR_PTR(-EOVERFLOW); + + cur = kzalloc(sizeof(*cur), GFP_KERNEL); + if (!cur) + cur = ERR_PTR(-ENOMEM); + cur->sw_msi_start = sw_msi_start; + cur->msi_addr = msi_addr; + cur->pgoff = max_pgoff; + cur->id = ictx->sw_msi_id++; + list_add_tail(&cur->sw_msi_item, &ictx->sw_msi_list); + return cur; +} + +static int iommufd_sw_msi_install(struct iommufd_ctx *ictx, + struct iommufd_hwpt_paging *hwpt_paging, + struct iommufd_sw_msi_map *msi_map) +{ + unsigned long iova; + + lockdep_assert_held(&ictx->sw_msi_lock); + + iova = msi_map->sw_msi_start + msi_map->pgoff * PAGE_SIZE; + if (!test_bit(msi_map->id, hwpt_paging->present_sw_msi.bitmap)) { + int rc; + + rc = iommu_map(hwpt_paging->common.domain, iova, + msi_map->msi_addr, PAGE_SIZE, + IOMMU_WRITE | IOMMU_READ | IOMMU_MMIO, + GFP_KERNEL_ACCOUNT); + if (rc) + return rc; + __set_bit(msi_map->id, hwpt_paging->present_sw_msi.bitmap); + } + return 0; +} + +static struct iommufd_attach_handle * +iommu_group_get_iommufd_handle(struct iommu_group *group) +{ + struct iommu_attach_handle *handle; + + handle = iommu_attach_handle_get(group, IOMMU_NO_PASID, 0); + if (IS_ERR(handle)) + return NULL; + return to_iommufd_handle(handle); +} + +/* + * Called by the irq code if the platform translates the MSI address through the + * IOMMU. msi_addr is the physical address of the MSI page. iommufd will + * allocate a fd global iova for the physical page that is the same on all + * domains and devices. + */ +#ifdef CONFIG_IRQ_MSI_IOMMU +int iommufd_sw_msi(struct iommu_domain *domain, struct msi_desc *desc, + phys_addr_t msi_addr) +{ + struct device *dev = msi_desc_to_dev(desc); + struct iommufd_hwpt_paging *hwpt_paging; + struct iommufd_attach_handle *handle; + struct iommufd_sw_msi_map *msi_map; + struct iommufd_ctx *ictx; + unsigned long iova; + int rc; + + handle = iommu_group_get_iommufd_handle(dev->iommu_group); + if (!handle) + return 0; + hwpt_paging = find_hwpt_paging(domain->iommufd_hwpt); + + /* No IOMMU_RESV_SW_MSI means no change to the msi_msg */ + if (handle->idev->igroup->sw_msi_start == PHYS_ADDR_MAX) + return 0; + + ictx = handle->idev->ictx; + guard(mutex)(&ictx->sw_msi_lock); + /* + * The input msi_addr is the exact byte offset of the MSI doorbell, we + * assume the caller has checked that it is contained with a MMIO region + * that is secure to map at PAGE_SIZE. + */ + msi_map = iommufd_sw_msi_get_map(handle->idev->ictx, + msi_addr & PAGE_MASK, + handle->idev->igroup->sw_msi_start); + if (IS_ERR(msi_map)) + return PTR_ERR(msi_map); + + rc = iommufd_sw_msi_install(ictx, hwpt_paging, msi_map); + if (rc) + return rc; + __set_bit(msi_map->id, handle->idev->igroup->required_sw_msi.bitmap); + + iova = msi_map->sw_msi_start + msi_map->pgoff * PAGE_SIZE; + msi_desc_set_iommu_msi_iova(desc, iova, PAGE_SHIFT); + return 0; +} +#endif + static int iommufd_group_setup_msi(struct iommufd_group *igroup, struct iommufd_hwpt_paging *hwpt_paging) { - phys_addr_t sw_msi_start = igroup->sw_msi_start; - int rc; + struct iommufd_ctx *ictx = igroup->ictx; + struct iommufd_sw_msi_map *cur; + + if (igroup->sw_msi_start == PHYS_ADDR_MAX) + return 0;
/* - * If the IOMMU driver gives a IOMMU_RESV_SW_MSI then it is asking us to - * call iommu_get_msi_cookie() on its behalf. This is necessary to setup - * the MSI window so iommu_dma_prepare_msi() can install pages into our - * domain after request_irq(). If it is not done interrupts will not - * work on this domain. - * - * FIXME: This is conceptually broken for iommufd since we want to allow - * userspace to change the domains, eg switch from an identity IOAS to a - * DMA IOAS. There is currently no way to create a MSI window that - * matches what the IRQ layer actually expects in a newly created - * domain. + * Install all the MSI pages the device has been using into the domain */ - if (sw_msi_start != PHYS_ADDR_MAX && !hwpt_paging->msi_cookie) { - rc = iommu_get_msi_cookie(hwpt_paging->common.domain, - sw_msi_start); + guard(mutex)(&ictx->sw_msi_lock); + list_for_each_entry(cur, &ictx->sw_msi_list, sw_msi_item) { + int rc; + + if (cur->sw_msi_start != igroup->sw_msi_start || + !test_bit(cur->id, igroup->required_sw_msi.bitmap)) + continue; + + rc = iommufd_sw_msi_install(ictx, hwpt_paging, cur); if (rc) return rc; - - /* - * iommu_get_msi_cookie() can only be called once per domain, - * it returns -EBUSY on later calls. - */ - hwpt_paging->msi_cookie = true; } return 0; } @@ -386,17 +503,8 @@ static int iommufd_hwpt_attach_device(struct iommufd_hw_pagetable *hwpt, return rc; }
-static struct iommufd_attach_handle * -iommufd_device_get_attach_handle(struct iommufd_device *idev) -{ - struct iommu_attach_handle *handle; - - handle = - iommu_attach_handle_get(idev->igroup->group, IOMMU_NO_PASID, 0); - if (IS_ERR(handle)) - return NULL; - return to_iommufd_handle(handle); -} +#define iommufd_device_get_attach_handle(idev) \ + iommu_group_get_iommufd_handle(idev->igroup->group)
static void iommufd_hwpt_detach_device(struct iommufd_hw_pagetable *hwpt, struct iommufd_device *idev) diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c index 2641d50f46cf..7de6e914232e 100644 --- a/drivers/iommu/iommufd/hw_pagetable.c +++ b/drivers/iommu/iommufd/hw_pagetable.c @@ -156,6 +156,7 @@ iommufd_hwpt_paging_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas, goto out_abort; } } + iommu_domain_set_sw_msi(hwpt->domain, iommufd_sw_msi);
/* * Set the coherency mode before we do iopt_table_add_domain() as some @@ -251,6 +252,7 @@ iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx, goto out_abort; } hwpt->domain->owner = ops; + iommu_domain_set_sw_msi(hwpt->domain, iommufd_sw_msi);
if (WARN_ON_ONCE(hwpt->domain->type != IOMMU_DOMAIN_NESTED)) { rc = -EINVAL; @@ -307,6 +309,7 @@ iommufd_viommu_alloc_hwpt_nested(struct iommufd_viommu *viommu, u32 flags, goto out_abort; } hwpt->domain->owner = viommu->iommu_dev->ops; + iommu_domain_set_sw_msi(hwpt->domain, iommufd_sw_msi);
if (WARN_ON_ONCE(hwpt->domain->type != IOMMU_DOMAIN_NESTED)) { rc = -EINVAL; diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c index ccf616462a1c..b6fa9fd11bc1 100644 --- a/drivers/iommu/iommufd/main.c +++ b/drivers/iommu/iommufd/main.c @@ -227,6 +227,8 @@ static int iommufd_fops_open(struct inode *inode, struct file *filp) xa_init(&ictx->groups); ictx->file = filp; init_waitqueue_head(&ictx->destroy_wait); + mutex_init(&ictx->sw_msi_lock); + INIT_LIST_HEAD(&ictx->sw_msi_list); filp->private_data = ictx; return 0; } @@ -234,6 +236,8 @@ static int iommufd_fops_open(struct inode *inode, struct file *filp) static int iommufd_fops_release(struct inode *inode, struct file *filp) { struct iommufd_ctx *ictx = filp->private_data; + struct iommufd_sw_msi_map *next; + struct iommufd_sw_msi_map *cur; struct iommufd_object *obj;
/* @@ -262,6 +266,11 @@ static int iommufd_fops_release(struct inode *inode, struct file *filp) break; } WARN_ON(!xa_empty(&ictx->groups)); + + mutex_destroy(&ictx->sw_msi_lock); + list_for_each_entry_safe(cur, next, &ictx->sw_msi_list, sw_msi_item) + kfree(cur); + kfree(ictx); return 0; }