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Thu, 20 Aug 2026 14:41:55 -0700 (PDT) X-Received: by 2002:a05:622a:164f:b0:52d:3352:f7ac with SMTP id d75a77b69052e-52df5a15479mr14185171cf.28.1787262115417; Thu, 20 Aug 2026 14:41:55 -0700 (PDT) Received: from localhost ([193.165.40.195]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-482b14d05a6sm16373207f8f.35.2026.08.20.14.41.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Aug 2026 14:41:54 -0700 (PDT) From: Andrew Jones 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 v4 01/21] iommufd: Convert struct iommufd_sw_msi_maps to a growable bitmap Date: Thu, 20 Aug 2026 23:41:30 +0200 Message-ID: <20260820214150.545737-2-andrew.jones@oss.qualcomm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260820214150.545737-1-andrew.jones@oss.qualcomm.com> References: <20260820214150.545737-1-andrew.jones@oss.qualcomm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Proofpoint-GUID: l77rFMJHEiI4HzYXJxJdKze4QDw5a5pL X-Proofpoint-Spam-Info: AW1haW4tMjYwODIwMDE2MiBTYWx0ZWRfX/6rNnDLM9Hun nl6Kjp3WYRDLMcfr08SNlMwEO+zsrFoLtp1kSSPnKeajIP37sdFEd2i8V6g8bCxWP4RQRtyIzAT u/VKwncTBZfR79nQP8lbQemtq3MM1gY= X-Authority-Analysis: v=2.4 cv=T/O8ifKQ c=1 sm=1 tr=0 ts=6a8774a4 cx=c_pps a=EVbN6Ke/fEF3bsl7X48z0g==:117 a=CzrpMg+lqiTzknPDBj2tlw==:17 a=Sv0fKeRqtYgA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=rJkE3RaqiGZ5pbrm-msn:22 a=EUspDBNiAAAA:8 a=8L5tTrZ4L9qXjquGIIcA:9 a=a_PwQJl-kcHnX1M80qC6:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODIwMDE2MiBTYWx0ZWRfX0PeGrh1cAl2Z wvE7HALQK8yHyYrinGYo9qyHs5su01MHVuQkQmixNZvP5tUUGGGLnT3RwfP0LrS17Z6h9LJTG22 EZ40N9qsKtHf/kfJ1jt6p6x3mI++H4gIAlVdH2PzehpxJJmWK5slHDtmcEZ617e9OQKj4rG4Jvo ckJ+BcPAWWunEeGQRY6PNr9dJK+1WQxjB1q3NkECRs1A5eYIsoUJDjhV5Q7yP4TBqWFow2YuPWR bGjzZFW5yhHOEohje5ff1QbBC3I6W7n7aV63+Usg/uddjxhGHr+Fs74y99JSMgjS6pHxGCR1766 IqKPk//F4rsyi9pHBAlAH0pFWN8hXINVuSuMj30g9jgoxUGqrveWj1qgEvMpsACmOBK2CcVcNEB 98VrtxDUqT79MzP9peWR3kQ7p3UwDtM7Arjymca9kxqBLxnWXHeiAbBLPFMjBnLthDOXzQEaw1G r6WKUE2bL+FgN7VqVtw== X-Proofpoint-ORIG-GUID: l77rFMJHEiI4HzYXJxJdKze4QDw5a5pL X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-20_02,2026-08-20_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 lowpriorityscore=0 phishscore=0 clxscore=1015 bulkscore=0 spamscore=0 adultscore=0 priorityscore=1501 impostorscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608200162 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 --- drivers/iommu/iommufd/device.c | 3 +- drivers/iommu/iommufd/driver.c | 38 +++++++++++++++-------- drivers/iommu/iommufd/hw_pagetable.c | 1 + drivers/iommu/iommufd/iommufd_private.h | 41 +++++++++++++++++++++++-- 4 files changed, 67 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..9b9316ae4266 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 +224,26 @@ 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 +297,11 @@ 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 #include #include +#include #include #include #include @@ -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