From: Jason Gunthorpe <jgg@xxxxxxxxxx>
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
loaded into a domain before it is attached ensuring that MSI is not
disrupted.
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
[nicolinc: set sw_msi pointer in nested hwpt allocators]
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
drivers/iommu/iommufd/iommufd_private.h | 23 +++-
drivers/iommu/iommufd/device.c | 158 ++++++++++++++++++++----
drivers/iommu/iommufd/hw_pagetable.c | 3 +
drivers/iommu/iommufd/main.c | 9 ++
4 files changed, 170 insertions(+), 23 deletions(-)
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 063c0a42f54f..3e83bbb5912c 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 38b31b652147..f75b3c23cd41 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 +294,149 @@ 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;
+}
+
+/*
+ * 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 iommu_attach_handle *raw_handle;
+ 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;
+
+ raw_handle =
+ iommu_attach_handle_get(dev->iommu_group, IOMMU_NO_PASID, 0);
+ if (!raw_handle)
+ return 0;
+ hwpt_paging = find_hwpt_paging(domain->iommufd_hwpt);
+
+ handle = to_iommufd_handle(raw_handle);
+ /* 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
+
+/*
+ * FIXME: when a domain is removed any ids that are not in the union of
+ * all still attached devices should be removed.
+ */
+
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;
}
diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index f7c0d7b214b6..538484eecb3b 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;
@@ -303,6 +305,7 @@ 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 97c5e3567d33..7cc9497b7193 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;
}
--
2.43.0
