[PATCH v9 03/11] vfio: VFIO_IOMMU_SET_MSI_BINDING

Eric Auger
2019-07-11T13:57:02Z

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@redhat.com>

---

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 | 55 +++++++++++++++++++++++++++++++++
include/uapi/linux/vfio.h | 20 ++++++++++++
2 files changed, 75 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 307f059d3080..c858be878590 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1829,6 +1829,42 @@ static int vfio_cache_inv_fn(struct device *dev, void *data)
return iommu_cache_invalidate(dc->domain, dev, &ustruct->info);
}

+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 long vfio_iommu_type1_ioctl(void *iommu_data,
unsigned int cmd, unsigned long arg)
{
@@ -1936,6 +1972,25 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
&ustruct);
mutex_unlock(&iommu->lock);
return ret;
+ } else if (cmd == VFIO_IOMMU_SET_MSI_BINDING) {
+ struct vfio_iommu_type1_set_msi_binding ustruct;
+
+ minsz = offsetofend(struct vfio_iommu_type1_set_msi_binding,
+ size);
+
+ if (copy_from_user(&ustruct, (void __user *)arg, minsz))
+ return -EFAULT;
+
+ if (ustruct.argsz < minsz)
+ return -EINVAL;
+
+ if (ustruct.flags == VFIO_IOMMU_UNBIND_MSI)
+ vfio_unbind_msi(iommu, ustruct.iova);
+ else if (ustruct.flags == VFIO_IOMMU_BIND_MSI)
+ return vfio_bind_msi(iommu, ustruct.iova, ustruct.gpa,
+ ustruct.size);
+ else
+ return -EINVAL;
}

return -ENOTTY;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index b31c25b682c5..deadbd84f2cf 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -795,6 +795,26 @@ struct vfio_iommu_type1_cache_invalidate {
};
#define VFIO_IOMMU_CACHE_INVALIDATE _IO(VFIO_TYPE, VFIO_BASE + 23)

+/**
+ * VFIO_IOMMU_SET_MSI_BINDING - _IOWR(VFIO_TYPE, VFIO_BASE + 24,
+ * 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 + 24)
+
/* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */

/*
--
2.20.1