To provide the iommufd_sw_msi() to the iommu core that is under a different
Kconfig, move it and its related functions to driver.c. Then, stub it into
the public iommufd header. iommufd_sw_msi_install() continues to be used by
iommufd internal, so put it in the private header.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/iommufd/iommufd_private.h |   5 +-
 include/linux/iommufd.h                 |   9 ++
 drivers/iommu/iommufd/device.c          | 122 -----------------------
 drivers/iommu/iommufd/driver.c          | 124 ++++++++++++++++++++++++
 4 files changed, 136 insertions(+), 124 deletions(-)

diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 246297452a44..51da18672c74 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -32,8 +32,9 @@ 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);
+int iommufd_sw_msi_install(struct iommufd_ctx *ictx,
+			   struct iommufd_hwpt_paging *hwpt_paging,
+			   struct iommufd_sw_msi_map *msi_map);
 
 struct iommufd_ctx {
 	struct file *file;
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 11110c749200..2f272863a207 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -8,6 +8,7 @@
 
 #include <linux/err.h>
 #include <linux/errno.h>
+#include <linux/msi.h>
 #include <linux/refcount.h>
 #include <linux/types.h>
 #include <linux/xarray.h>
@@ -187,6 +188,8 @@ struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx,
 					     enum iommufd_object_type type);
 struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
 				       unsigned long vdev_id);
+int iommufd_sw_msi(struct iommu_domain *domain, struct msi_desc *desc,
+		   phys_addr_t msi_addr);
 #else /* !CONFIG_IOMMUFD_DRIVER_CORE */
 static inline struct iommufd_object *
 _iommufd_object_alloc(struct iommufd_ctx *ictx, size_t size,
@@ -200,6 +203,12 @@ iommufd_viommu_find_dev(struct iommufd_viommu *viommu, unsigned long vdev_id)
 {
 	return NULL;
 }
+
+static inline int iommufd_sw_msi(struct iommu_domain *domain,
+				 struct msi_desc *desc, phys_addr_t msi_addr)
+{
+	return -EOPNOTSUPP;
+}
 #endif /* CONFIG_IOMMUFD_DRIVER_CORE */
 
 /*
diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 6dccbf7217f5..9c1fe3170d16 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -294,128 +294,6 @@ 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 __maybe_unused 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 iommufd_hwpt_paging *hwpt_paging;
-	struct iommu_attach_handle *raw_handle;
-	struct iommufd_attach_handle *handle;
-	struct iommufd_sw_msi_map *msi_map;
-	struct iommufd_ctx *ictx;
-	unsigned long iova;
-	int rc;
-
-	/*
-	 * It is safe to call iommu_attach_handle_get() here because the iommu
-	 * core code invokes this under the group mutex which also prevents any
-	 * change of the attach handle for the duration of this function.
-	 */
-	iommu_group_mutex_assert(dev);
-
-	raw_handle =
-		iommu_attach_handle_get(dev->iommu_group, IOMMU_NO_PASID, 0);
-	if (IS_ERR(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
-
 static int iommufd_group_setup_msi(struct iommufd_group *igroup,
 				   struct iommufd_hwpt_paging *hwpt_paging)
 {
diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c
index 2d98b04ff1cb..999da79dfa36 100644
--- a/drivers/iommu/iommufd/driver.c
+++ b/drivers/iommu/iommufd/driver.c
@@ -49,5 +49,129 @@ struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
 }
 EXPORT_SYMBOL_NS_GPL(iommufd_viommu_find_dev, "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 __maybe_unused 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;
+}
+
+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;
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_sw_msi_install, "IOMMUFD");
+
+/*
+ * 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 iommu_attach_handle *raw_handle;
+	struct iommufd_attach_handle *handle;
+	struct iommufd_sw_msi_map *msi_map;
+	struct iommufd_ctx *ictx;
+	unsigned long iova;
+	int rc;
+
+	/*
+	 * It is safe to call iommu_attach_handle_get() here because the iommu
+	 * core code invokes this under the group mutex which also prevents any
+	 * change of the attach handle for the duration of this function.
+	 */
+	iommu_group_mutex_assert(dev);
+
+	raw_handle =
+		iommu_attach_handle_get(dev->iommu_group, IOMMU_NO_PASID, 0);
+	if (IS_ERR(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;
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_sw_msi, "IOMMUFD");
+#endif
+
 MODULE_DESCRIPTION("iommufd code shared with builtin modules");
 MODULE_LICENSE("GPL");
-- 
2.43.0

On Thu, Feb 27, 2025 at 05:31:16PM -0800, Nicolin Chen wrote:
> @@ -187,6 +188,8 @@ struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx,
>  					     enum iommufd_object_type type);
>  struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
>  				       unsigned long vdev_id);
> +int iommufd_sw_msi(struct iommu_domain *domain, struct msi_desc *desc,
> +		   phys_addr_t msi_addr);

This should probably go into drivers/iommu/iommu-priv.h ?

> +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;
> +}
> +EXPORT_SYMBOL_NS_GPL(iommufd_sw_msi_install, "IOMMUFD");

Stubbed out too if CONFIG_IRQ_MSI_IOMMU ?

I'm still wondering if we should use a function pointer, how big was
this compiled anyhow?

Jason

On Fri, Feb 28, 2025 at 01:32:12PM -0400, Jason Gunthorpe wrote:
> On Thu, Feb 27, 2025 at 05:31:16PM -0800, Nicolin Chen wrote:
> > @@ -187,6 +188,8 @@ struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx,
> >  					     enum iommufd_object_type type);
> >  struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
> >  				       unsigned long vdev_id);
> > +int iommufd_sw_msi(struct iommu_domain *domain, struct msi_desc *desc,
> > +		   phys_addr_t msi_addr);
> 
> This should probably go into drivers/iommu/iommu-priv.h ?

Oh right, I forgot we had that.

> > +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;
> > +}
> > +EXPORT_SYMBOL_NS_GPL(iommufd_sw_msi_install, "IOMMUFD");
> 
> Stubbed out too if CONFIG_IRQ_MSI_IOMMU ?

In that case, the other caller iommufd_group_setup_msi() could be
{
#if IS_ENABLED(CONFIG_IRQ_MSI_IOMMU)
	....
	iommufd_sw_msi_install();
	...
#endif
	return 0;
}
?

> I'm still wondering if we should use a function pointer, how big was
> this compiled anyhow?

Hmm, you mean the size of driver.o? It's 192K (before) vs 212K
(after).

Thanks
Nicolin

On Fri, Feb 28, 2025 at 09:54:28AM -0800, Nicolin Chen wrote:
> > Stubbed out too if CONFIG_IRQ_MSI_IOMMU ?
> 
> In that case, the other caller iommufd_group_setup_msi() could be
> {
> #if IS_ENABLED(CONFIG_IRQ_MSI_IOMMU)
> 	....
> 	iommufd_sw_msi_install();
> 	...
> #endif
> 	return 0;
> }
> ?

Or a empty static inline
 
> > I'm still wondering if we should use a function pointer, how big was
> > this compiled anyhow?
> 
> Hmm, you mean the size of driver.o? It's 192K (before) vs 212K
> (after).

Yes, but use the 'size' command to measure before/after

Jason

On Fri, Feb 28, 2025 at 02:02:15PM -0400, Jason Gunthorpe wrote:
> On Fri, Feb 28, 2025 at 09:54:28AM -0800, Nicolin Chen wrote:
> > > Stubbed out too if CONFIG_IRQ_MSI_IOMMU ?
> > 
> > In that case, the other caller iommufd_group_setup_msi() could be
> > {
> > #if IS_ENABLED(CONFIG_IRQ_MSI_IOMMU)
> > 	....
> > 	iommufd_sw_msi_install();
> > 	...
> > #endif
> > 	return 0;
> > }
> > ?
> 
> Or a empty static inline
>  
> > > I'm still wondering if we should use a function pointer, how big was
> > > this compiled anyhow?
> > 
> > Hmm, you mean the size of driver.o? It's 192K (before) vs 212K
> > (after).
> 
> Yes, but use the 'size' command to measure before/after

Before:
   text	   data	    bss	    dec	    hex	filename
    722	     44	      0	    766	    2fe	drivers/iommu/iommufd/driver.o
After:
   text	   data	    bss	    dec	    hex	filename
   1888	    100	      0	   1988	    7c4	drivers/iommu/iommufd/driver.o

Thanks
Nicolin