Linux-RISC-V Archive on lore.kernel.org
 help / color / mirror / Atom feed
From: Andrew Jones <andrew.jones@oss.qualcomm.com>
To: linux-riscv@lists.infradead.org, iommu@lists.linux.dev
Cc: linux-kernel@vger.kernel.org, tomasz.jeznach@linux.dev,
	tjeznach@rivosinc.com, jgg@ziepe.ca, jgg@nvidia.com,
	joro@8bytes.org, will@kernel.org, robin.murphy@arm.com,
	pjw@kernel.org, palmer@dabbelt.com, anup@brainfault.org,
	tglx@kernel.org, kevin.tian@intel.com,
	fangyu.yu@linux.alibaba.com
Subject: [PATCH v5 02/17] iommufd: Convert struct iommufd_sw_msi_maps to a growable bitmap
Date: Mon, 31 Aug 2026 16:59:28 +0200	[thread overview]
Message-ID: <20260831145943.313726-3-andrew.jones@oss.qualcomm.com> (raw)
In-Reply-To: <20260831145943.313726-1-andrew.jones@oss.qualcomm.com>

struct iommufd_sw_msi_maps uses a fixed 64-bit bitmap, limiting each
group and hardware page table to 64 software MSI mappings. RISC-V
interrupt remapping needs a mapping for every possible CPU, so this
limit is insufficient.

Make the bitmap grow on demand and treat IDs beyond its current size
as absent. Cap it at 16K entries to bound allocation size while leaving
ample room for expected software MSI users.

Signed-off-by: Andrew Jones <andrew.jones@oss.qualcomm.com>
---
 drivers/iommu/iommufd/device.c          |  3 +-
 drivers/iommu/iommufd/driver.c          | 37 ++++++++++++++--------
 drivers/iommu/iommufd/hw_pagetable.c    |  1 +
 drivers/iommu/iommufd/iommufd_private.h | 41 +++++++++++++++++++++++--
 4 files changed, 66 insertions(+), 16 deletions(-)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index d488c23fd353..868f1e591208 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -34,6 +34,7 @@ static void iommufd_group_release(struct kref *kref)
 		   NULL, GFP_KERNEL);
 	iommu_group_put(igroup->group);
 	mutex_destroy(&igroup->lock);
+	kfree(igroup->required_sw_msi.bitmap);
 	kfree(igroup);
 }
 
@@ -384,7 +385,7 @@ static int iommufd_group_setup_msi(struct iommufd_group *igroup,
 		int rc;
 
 		if (cur->sw_msi_start != igroup->sw_msi_start ||
-		    !test_bit(cur->id, igroup->required_sw_msi.bitmap))
+		    !iommufd_sw_msi_maps_test_bit(&igroup->required_sw_msi, cur->id))
 			continue;
 
 		rc = iommufd_sw_msi_install(ictx, hwpt_paging, cur);
diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c
index 3b8067976eac..d0b05b1fda42 100644
--- a/drivers/iommu/iommufd/driver.c
+++ b/drivers/iommu/iommufd/driver.c
@@ -196,13 +196,15 @@ iommufd_sw_msi_get_map(struct iommufd_ctx *ictx, phys_addr_t msi_addr,
 	list_for_each_entry(cur, &ictx->sw_msi_list, sw_msi_item) {
 		if (cur->sw_msi_start != sw_msi_start)
 			continue;
+		if (cur->pgoff == UINT_MAX)
+			return ERR_PTR(-EOVERFLOW);
 		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))
+	if (ictx->sw_msi_id > IOMMUFD_SW_MSI_MAX_ID ||
+	    max_pgoff > (ULONG_MAX - sw_msi_start) / PAGE_SIZE)
 		return ERR_PTR(-EOVERFLOW);
 
 	cur = kzalloc_obj(*cur);
@@ -222,21 +224,25 @@ int iommufd_sw_msi_install(struct iommufd_ctx *ictx,
 			   struct iommufd_sw_msi_map *msi_map)
 {
 	unsigned long iova;
+	int rc;
 
 	lockdep_assert_held(&ictx->sw_msi_lock);
 
+	if (iommufd_sw_msi_maps_test_bit(&hwpt_paging->present_sw_msi, msi_map->id))
+		return 0;
+
 	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);
-	}
+	rc = iommufd_sw_msi_maps_ensure(&hwpt_paging->present_sw_msi, msi_map->id);
+	if (rc)
+		return 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_INTERNAL");
@@ -290,6 +296,11 @@ int iommufd_sw_msi(struct iommu_domain *domain, struct msi_desc *desc,
 	if (IS_ERR(msi_map))
 		return PTR_ERR(msi_map);
 
+	rc = iommufd_sw_msi_maps_ensure(&handle->idev->igroup->required_sw_msi,
+					msi_map->id);
+	if (rc)
+		return rc;
+
 	rc = iommufd_sw_msi_install(ictx, hwpt_paging, msi_map);
 	if (rc)
 		return rc;
diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 623cc608ca0c..54873de43eb0 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -32,6 +32,7 @@ void iommufd_hwpt_paging_destroy(struct iommufd_object *obj)
 	}
 
 	__iommufd_hwpt_destroy(&hwpt_paging->common);
+	kfree(hwpt_paging->present_sw_msi.bitmap);
 	refcount_dec(&hwpt_paging->ioas->obj.users);
 }
 
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 43fbc5bed8de..9ca5f9f92cdf 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -9,6 +9,7 @@
 #include <linux/iova_bitmap.h>
 #include <linux/maple_tree.h>
 #include <linux/rwsem.h>
+#include <linux/slab.h>
 #include <linux/uaccess.h>
 #include <linux/xarray.h>
 #include <uapi/linux/iommufd.h>
@@ -29,11 +30,47 @@ struct iommufd_sw_msi_map {
 	unsigned int id;
 };
 
-/* Bitmap of struct iommufd_sw_msi_map::id */
+/* Bitmap of struct iommufd_sw_msi_map::id; starts empty, grows on demand. */
 struct iommufd_sw_msi_maps {
-	DECLARE_BITMAP(bitmap, 64);
+	unsigned long *bitmap;
+	unsigned int nbits;
 };
 
+/* Large enough for foreseeable SW MSI users while bounding bitmap growth. */
+#define IOMMUFD_SW_MSI_MAX_ID	(16U * 1024 - 1)
+
+/* Grow bitmap to accommodate id. Must be called under ictx->sw_msi_lock. */
+static inline int iommufd_sw_msi_maps_ensure(struct iommufd_sw_msi_maps *maps,
+					     unsigned int id)
+{
+	unsigned long *new_bitmap;
+	unsigned int new_nbits;
+
+	if (id < maps->nbits)
+		return 0;
+	if (id > IOMMUFD_SW_MSI_MAX_ID)
+		return -EOVERFLOW;
+
+	new_nbits = max(ALIGN(id + 1, BITS_PER_LONG), 64U);
+	new_bitmap = krealloc(maps->bitmap,
+			      BITS_TO_LONGS(new_nbits) * sizeof(unsigned long),
+			      GFP_KERNEL_ACCOUNT);
+	if (!new_bitmap)
+		return -ENOMEM;
+	bitmap_clear(new_bitmap, maps->nbits, new_nbits - maps->nbits);
+	maps->bitmap = new_bitmap;
+	maps->nbits = new_nbits;
+	return 0;
+}
+
+static inline bool iommufd_sw_msi_maps_test_bit(const struct iommufd_sw_msi_maps *maps,
+						unsigned int id)
+{
+	if (id >= maps->nbits)
+		return false;
+	return test_bit(id, maps->bitmap);
+}
+
 #ifdef CONFIG_IRQ_MSI_IOMMU
 int iommufd_sw_msi_install(struct iommufd_ctx *ictx,
 			   struct iommufd_hwpt_paging *hwpt_paging,
-- 
2.43.0


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  parent reply	other threads:[~2026-08-31 15:00 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-31 14:59 [PATCH v5 00/17] iommu/riscv: Enable MSI remapping, IOMMU_DMA and VFIO Andrew Jones
2026-08-31 14:59 ` [PATCH v5 01/17] iommu/dma: Prepare MSI physical address lists Andrew Jones
2026-08-31 14:59 ` Andrew Jones [this message]
2026-09-01  7:52   ` [PATCH v5 02/17] iommufd: Convert struct iommufd_sw_msi_maps to a growable bitmap Nutty.Liu
2026-08-31 14:59 ` [PATCH v5 03/17] iommufd: Split software MSI map lookup and allocation Andrew Jones
2026-08-31 14:59 ` [PATCH v5 04/17] iommufd: Bound software MSI mappings to the reserved range Andrew Jones
2026-08-31 14:59 ` [PATCH v5 05/17] iommufd: Prepare software MSI maps for address lists Andrew Jones
2026-08-31 14:59 ` [PATCH v5 06/17] iommufd: Install software MSI map ranges atomically Andrew Jones
2026-08-31 14:59 ` [PATCH v5 07/17] iommufd: Prepare software MSI installation for address lists Andrew Jones
2026-08-31 14:59 ` [PATCH v5 08/17] iommu/dma: Introduce iommu_dma_prepare_msi_list() Andrew Jones
2026-08-31 14:59 ` [PATCH v5 09/17] iommu/riscv: Report cache coherency capability Andrew Jones
2026-08-31 14:59 ` [PATCH v5 10/17] iommu/riscv: Reserve an MSI IOVA window for iommufd Andrew Jones
2026-08-31 14:59 ` [PATCH v5 11/17] irqchip/riscv-imsic: Add S-mode MSI address list Andrew Jones
2026-09-01 13:38   ` Andrew Jones
2026-08-31 14:59 ` [PATCH v5 12/17] irqchip/riscv-imsic: Support IOMMU MSI address lists Andrew Jones
2026-08-31 14:59 ` [PATCH v5 13/17] iommu/dma: Enable IOMMU_DMA for 64-bit RISC-V Andrew Jones
2026-08-31 14:59 ` [PATCH v5 14/17] vfio: enable IOMMU_TYPE1 for RISC-V Andrew Jones
2026-08-31 14:59 ` [PATCH v5 15/17] RISC-V: KVM: Enable KVM_VFIO interfaces on RISC-V arch Andrew Jones
2026-08-31 14:59 ` [PATCH v5 16/17] riscv: defconfig: Enable IOMMUFD and VFIO Andrew Jones
2026-08-31 14:59 ` [PATCH v5 17/17] selftests/vfio: Allow building on RISC-V Andrew Jones
2026-09-08 13:08 ` [PATCH v5 00/17] iommu/riscv: Enable MSI remapping, IOMMU_DMA and VFIO fangyu.yu

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20260831145943.313726-3-andrew.jones@oss.qualcomm.com \
    --to=andrew.jones@oss.qualcomm.com \
    --cc=anup@brainfault.org \
    --cc=fangyu.yu@linux.alibaba.com \
    --cc=iommu@lists.linux.dev \
    --cc=jgg@nvidia.com \
    --cc=jgg@ziepe.ca \
    --cc=joro@8bytes.org \
    --cc=kevin.tian@intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=palmer@dabbelt.com \
    --cc=pjw@kernel.org \
    --cc=robin.murphy@arm.com \
    --cc=tglx@kernel.org \
    --cc=tjeznach@rivosinc.com \
    --cc=tomasz.jeznach@linux.dev \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox