Re: [PATCH v3 3/3] iommu: Drop sw_msi from iommu_domain

From: Robin Murphy
Date: Tue Mar 04 2025 - 10:02:34 EST

On 03/03/2025 8:52 pm, Nicolin Chen wrote:
There are only two sw_msi implementations in the entire system, thus it's
not very necessary to have an sw_msi pointer.

Instead, check domain->private_data_owner to call the two implementations
directly from the core code.

FWIW I still wish this was squashed into the pending patches so we're not adding stuff we immediately remove again, but oh well, what's done is done.

Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>

(assuming this isn't also queued already given that once again I've had the audacity to not look at my inbox until after 2PM the day after it was posted...)

Suggested-by: Robin Murphy <robin.murphy@xxxxxxx>
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
drivers/iommu/dma-iommu.h | 9 +++++++++
include/linux/iommu.h | 15 ---------------
drivers/iommu/dma-iommu.c | 14 ++------------
drivers/iommu/iommu.c | 17 +++++++++++++++--
drivers/iommu/iommufd/hw_pagetable.c | 3 ---
5 files changed, 26 insertions(+), 32 deletions(-)

diff --git a/drivers/iommu/dma-iommu.h b/drivers/iommu/dma-iommu.h
index 9cca11806e5d..eca201c1f963 100644
--- a/drivers/iommu/dma-iommu.h
+++ b/drivers/iommu/dma-iommu.h
@@ -19,6 +19,9 @@ int iommu_dma_init_fq(struct iommu_domain *domain);
void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list);
+int iommu_dma_sw_msi(struct iommu_domain *domain, struct msi_desc *desc,
+ phys_addr_t msi_addr);
+
extern bool iommu_dma_forcedac;
#else /* CONFIG_IOMMU_DMA */
@@ -49,5 +52,11 @@ static inline void iommu_dma_get_resv_regions(struct device *dev, struct list_he
{
}
+static inline int iommu_dma_sw_msi(struct iommu_domain *domain,
+ struct msi_desc *desc, phys_addr_t msi_addr)
+{
+ return -ENODEV;
+}
+
#endif /* CONFIG_IOMMU_DMA */
#endif /* __DMA_IOMMU_H */
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 06cc14e9993d..e01c855ae8a7 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -229,11 +229,6 @@ struct iommu_domain {
struct iommu_domain_geometry geometry;
int (*iopf_handler)(struct iopf_group *group);
-#if IS_ENABLED(CONFIG_IRQ_MSI_IOMMU)
- int (*sw_msi)(struct iommu_domain *domain, struct msi_desc *desc,
- phys_addr_t msi_addr);
-#endif
-
union { /* cookie */
struct iommu_dma_cookie *iova_cookie;
struct iommu_dma_msi_cookie *msi_cookie;
@@ -254,16 +249,6 @@ struct iommu_domain {
};
};
-static inline void iommu_domain_set_sw_msi(
- struct iommu_domain *domain,
- int (*sw_msi)(struct iommu_domain *domain, struct msi_desc *desc,
- phys_addr_t msi_addr))
-{
-#if IS_ENABLED(CONFIG_IRQ_MSI_IOMMU)
- domain->sw_msi = sw_msi;
-#endif
-}
-
static inline bool iommu_is_dma_domain(struct iommu_domain *domain)
{
return domain->type & __IOMMU_DOMAIN_DMA_API;
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index bc9bb9cb70c8..96e9f8d0a4f6 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -94,9 +94,6 @@ static int __init iommu_dma_forcedac_setup(char *str)
}
early_param("iommu.forcedac", iommu_dma_forcedac_setup);
-static int iommu_dma_sw_msi(struct iommu_domain *domain, struct msi_desc *desc,
- phys_addr_t msi_addr);
-
/* Number of entries per flush queue */
#define IOVA_DEFAULT_FQ_SIZE 256
#define IOVA_SINGLE_FQ_SIZE 32768
@@ -377,7 +374,6 @@ int iommu_get_dma_cookie(struct iommu_domain *domain)
mutex_init(&cookie->mutex);
INIT_LIST_HEAD(&cookie->msi_page_list);
- iommu_domain_set_sw_msi(domain, iommu_dma_sw_msi);
domain->cookie_type = IOMMU_COOKIE_DMA_IOVA;
domain->iova_cookie = cookie;
return 0;
@@ -411,7 +407,6 @@ int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base)
cookie->msi_iova = base;
INIT_LIST_HEAD(&cookie->msi_page_list);
- iommu_domain_set_sw_msi(domain, iommu_dma_sw_msi);
domain->cookie_type = IOMMU_COOKIE_DMA_MSI;
domain->msi_cookie = cookie;
return 0;
@@ -427,11 +422,6 @@ void iommu_put_dma_cookie(struct iommu_domain *domain)
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iommu_dma_msi_page *msi, *tmp;
-#if IS_ENABLED(CONFIG_IRQ_MSI_IOMMU)
- if (domain->sw_msi != iommu_dma_sw_msi)
- return;
-#endif
-
if (cookie->iovad.granule) {
iommu_dma_free_fq(cookie);
put_iova_domain(&cookie->iovad);
@@ -1825,8 +1815,8 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
return NULL;
}
-static int iommu_dma_sw_msi(struct iommu_domain *domain, struct msi_desc *desc,
- phys_addr_t msi_addr)
+int iommu_dma_sw_msi(struct iommu_domain *domain, struct msi_desc *desc,
+ phys_addr_t msi_addr)
{
struct device *dev = msi_desc_to_dev(desc);
const struct iommu_dma_msi_page *msi_page;
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 8b9423340221..c1c0656f41ef 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -18,6 +18,7 @@
#include <linux/errno.h>
#include <linux/host1x_context_bus.h>
#include <linux/iommu.h>
+#include <linux/iommufd.h>
#include <linux/idr.h>
#include <linux/err.h>
#include <linux/pci.h>
@@ -3649,8 +3650,20 @@ int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr)
return 0;
mutex_lock(&group->mutex);
- if (group->domain && group->domain->sw_msi)
- ret = group->domain->sw_msi(group->domain, desc, msi_addr);
+ if (group->domain) {
+ switch (group->domain->cookie_type) {
+ case IOMMU_COOKIE_DMA_MSI:
+ case IOMMU_COOKIE_DMA_IOVA:
+ ret = iommu_dma_sw_msi(group->domain, desc, msi_addr);
+ break;
+ case IOMMU_COOKIE_IOMMUFD:
+ ret = iommufd_sw_msi(group->domain, desc, msi_addr);
+ break;
+ default:
+ ret = -EOPNOTSUPP;
+ break;
+ }
+ }
mutex_unlock(&group->mutex);
return ret;
}
diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 227514030655..98aecf904902 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -156,7 +156,6 @@ 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
@@ -252,7 +251,6 @@ 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;
@@ -309,7 +307,6 @@ 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;