[PATCH v12 03/13] vfio: VFIO_IOMMU_SET_MSI_BINDING

From: Eric Auger
Date: Tue Feb 23 2021 - 16:10:01 EST


This patch adds the VFIO_IOMMU_SET_MSI_BINDING ioctl which aim
to (un)register the guest MSI binding to the host. This latter
then can use those stage 1 bindings to build a nested stage
binding targeting the physical MSIs.

Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>

---

v11 -> v12:
- Share VFIO_BASE + 20 with VFIO_IOMMU_SPAPR_TCE_REMOVE
- rework returned values

v10 -> v11:
- renamed ustruct into msi_binding
- return 0 on unbind

v8 -> v9:
- merge VFIO_IOMMU_BIND_MSI/VFIO_IOMMU_UNBIND_MSI into a single
VFIO_IOMMU_SET_MSI_BINDING ioctl
- ioctl id changed

v6 -> v7:
- removed the dev arg

v3 -> v4:
- add UNBIND
- unwind on BIND error

v2 -> v3:
- adapt to new proto of bind_guest_msi
- directly use vfio_iommu_for_each_dev

v1 -> v2:
- s/vfio_iommu_type1_guest_msi_binding/vfio_iommu_type1_bind_guest_msi
---
drivers/vfio/vfio_iommu_type1.c | 62 +++++++++++++++++++++++++++++++++
include/uapi/linux/vfio.h | 20 +++++++++++
2 files changed, 82 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index b4057ce809b0..0e6af4fe8c3d 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -2655,6 +2655,41 @@ static int vfio_cache_inv_fn(struct device *dev, void *data)
return iommu_uapi_cache_invalidate(dc->domain, dev, (void __user *)arg);
}

+static int
+vfio_bind_msi(struct vfio_iommu *iommu,
+ dma_addr_t giova, phys_addr_t gpa, size_t size)
+{
+ struct vfio_domain *d;
+ int ret = 0;
+
+ mutex_lock(&iommu->lock);
+
+ list_for_each_entry(d, &iommu->domain_list, next) {
+ ret = iommu_bind_guest_msi(d->domain, giova, gpa, size);
+ if (ret)
+ goto unwind;
+ }
+ goto unlock;
+unwind:
+ list_for_each_entry_continue_reverse(d, &iommu->domain_list, next) {
+ iommu_unbind_guest_msi(d->domain, giova);
+ }
+unlock:
+ mutex_unlock(&iommu->lock);
+ return ret;
+}
+
+static void
+vfio_unbind_msi(struct vfio_iommu *iommu, dma_addr_t giova)
+{
+ struct vfio_domain *d;
+
+ mutex_lock(&iommu->lock);
+ list_for_each_entry(d, &iommu->domain_list, next)
+ iommu_unbind_guest_msi(d->domain, giova);
+ mutex_unlock(&iommu->lock);
+}
+
static int vfio_iommu_migration_build_caps(struct vfio_iommu *iommu,
struct vfio_info_cap *caps)
{
@@ -2859,6 +2894,31 @@ static int vfio_iommu_type1_cache_invalidate(struct vfio_iommu *iommu,
return ret;
}

+static int vfio_iommu_type1_set_msi_binding(struct vfio_iommu *iommu,
+ unsigned long arg)
+{
+ struct vfio_iommu_type1_set_msi_binding msi_binding;
+ unsigned long minsz;
+
+ minsz = offsetofend(struct vfio_iommu_type1_set_msi_binding,
+ size);
+
+ if (copy_from_user(&msi_binding, (void __user *)arg, minsz))
+ return -EFAULT;
+
+ if (msi_binding.argsz < minsz)
+ return -EINVAL;
+
+ if (msi_binding.flags == VFIO_IOMMU_UNBIND_MSI) {
+ vfio_unbind_msi(iommu, msi_binding.iova);
+ return 0;
+ } else if (msi_binding.flags == VFIO_IOMMU_BIND_MSI) {
+ return vfio_bind_msi(iommu, msi_binding.iova,
+ msi_binding.gpa, msi_binding.size);
+ }
+ return -EINVAL;
+}
+
static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu,
unsigned long arg)
{
@@ -2983,6 +3043,8 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
return vfio_iommu_type1_set_pasid_table(iommu, arg);
case VFIO_IOMMU_CACHE_INVALIDATE:
return vfio_iommu_type1_cache_invalidate(iommu, arg);
+ case VFIO_IOMMU_SET_MSI_BINDING:
+ return vfio_iommu_type1_set_msi_binding(iommu, arg);
default:
return -ENOTTY;
}
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index ee6747ff8006..4c82e8f21618 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -1213,6 +1213,26 @@ struct vfio_iommu_type1_cache_invalidate {
};
#define VFIO_IOMMU_CACHE_INVALIDATE _IO(VFIO_TYPE, VFIO_BASE + 19)

+/**
+ * VFIO_IOMMU_SET_MSI_BINDING - _IOWR(VFIO_TYPE, VFIO_BASE + 20,
+ * struct vfio_iommu_type1_set_msi_binding)
+ *
+ * Pass a stage 1 MSI doorbell mapping to the host so that this
+ * latter can build a nested stage2 mapping. Or conversely tear
+ * down a previously bound stage 1 MSI binding.
+ */
+struct vfio_iommu_type1_set_msi_binding {
+ __u32 argsz;
+ __u32 flags;
+#define VFIO_IOMMU_BIND_MSI (1 << 0)
+#define VFIO_IOMMU_UNBIND_MSI (1 << 1)
+ __u64 iova; /* MSI guest IOVA */
+ /* Fields below are used on BIND */
+ __u64 gpa; /* MSI guest physical address */
+ __u64 size; /* size of stage1 mapping (bytes) */
+};
+#define VFIO_IOMMU_SET_MSI_BINDING _IO(VFIO_TYPE, VFIO_BASE + 20)
+
/* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */

/*
--
2.26.2