backends/iommufd: Introduce iommufd_backend_viommu_mmap
Add a backend helper to mmap hardware MMIO regions exposed via iommufd for a vIOMMU instance. This allows user space to access HW-accelerated MMIO pages provided by the vIOMMU. The caller is responsible for unmapping the returned region. Signed-off-by: Nicolin Chen <nicolinc@nvidia.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com> Tested-by: Eric Auger <eric.auger@redhat.com> Message-id: 20260609112552.378999-5-skolothumtho@nvidia.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Nicolin Chen committed
Jun 9, 2026 at 12:25 UTC
b391e41e53b5268d0943c4f2276749a9448496b3
3 files changed
+27
backends/iommufd.c
+22
@@ -580,6 +580,28 @@ bool iommufd_backend_alloc_hw_queue(IOMMUFDBackend *be, uint32_t viommu_id,
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return true;
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}
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+/*
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+ * Helper to mmap HW MMIO regions exposed via iommufd for a vIOMMU instance.
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+ * The caller is responsible for unmapping the mapped region.
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+ */
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+bool iommufd_backend_viommu_mmap(IOMMUFDBackend *be, uint32_t viommu_id,
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+ uint64_t size, off_t offset, void **out_ptr,
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+ Error **errp)
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+{
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+ g_assert(viommu_id);
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+ g_assert(out_ptr);
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+
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+ *out_ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, be->fd,
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+ offset);
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+ trace_iommufd_backend_viommu_mmap(be->fd, viommu_id, size, offset);
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+ if (*out_ptr == MAP_FAILED) {
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+ error_setg_errno(errp, errno, "IOMMUFD vIOMMU mmap failed");
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+ return false;
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+ }
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+
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+ return true;
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+}
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+
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bool host_iommu_device_iommufd_attach_hwpt(HostIOMMUDeviceIOMMUFD *hiodi,
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uint32_t hwpt_id, Error **errp)
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{
backends/trace-events
+1
@@ -25,6 +25,7 @@ iommufd_backend_alloc_viommu(int iommufd, uint32_t dev_id, uint32_t type, uint32
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iommufd_backend_alloc_vdev(int iommufd, uint32_t dev_id, uint32_t viommu_id, uint64_t virt_id, uint32_t vdev_id, int ret) " iommufd=%d dev_id=%u viommu_id=%u virt_id=0x%"PRIx64" vdev_id=%u (%d)"
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iommufd_viommu_alloc_eventq(int iommufd, uint32_t viommu_id, uint32_t type, uint32_t veventq_id, uint32_t veventq_fd, int ret) " iommufd=%d viommu_id=%u type=%u veventq_id=%u veventq_fd=%u (%d)"
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iommufd_backend_alloc_hw_queue(int iommufd, uint32_t viommu_id, uint32_t queue_type, uint32_t index, uint64_t addr, uint64_t size, uint32_t queue_id, int ret) " iommufd=%d viommu_id=%u queue_type=%u index=%u addr=0x%"PRIx64" size=0x%"PRIx64" queue_id=%u (%d)"
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+iommufd_backend_viommu_mmap(int iommufd, uint32_t viommu_id, uint64_t size, uint64_t offset) " iommufd=%d viommu_id=%u size=0x%"PRIx64" offset=0x%"PRIx64
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# igvm-cfg.c
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igvm_reset_enter(int type) "type=%u"
include/system/iommufd.h
+4
@@ -112,6 +112,10 @@ bool iommufd_backend_alloc_hw_queue(IOMMUFDBackend *be, uint32_t viommu_id,
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uint64_t addr, uint64_t length,
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uint32_t *out_hw_queue_id, Error **errp);
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+bool iommufd_backend_viommu_mmap(IOMMUFDBackend *be, uint32_t viommu_id,
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+ uint64_t size, off_t offset, void **out_ptr,
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+ Error **errp);
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+
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bool iommufd_backend_set_dirty_tracking(IOMMUFDBackend *be, uint32_t hwpt_id,
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bool start, Error **errp);
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bool iommufd_backend_get_dirty_bitmap(IOMMUFDBackend *be, uint32_t hwpt_id,