[PATCH v8 24/29] vfio: VFIO_IOMMU_BIND/UNBIND_MSI

[Eric Auger]

This patch adds the VFIO_IOMMU_BIND/UNBIND_MSI ioctl which aim
to pass/withdraw the guest MSI binding to/from the host.

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

---
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 | 64 +++++++++++++++++++++++++++++++++
 include/uapi/linux/vfio.h       | 29 +++++++++++++++
 2 files changed, 93 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 6fda4fbc9bfa..18142cb078a3 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1832,6 +1832,42 @@ 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 +1972,34 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
 					    &ustruct);
 		mutex_unlock(&iommu->lock);
 		return ret;
+	} else if (cmd == VFIO_IOMMU_BIND_MSI) {
+		struct vfio_iommu_type1_bind_msi ustruct;
+
+		minsz = offsetofend(struct vfio_iommu_type1_bind_msi,
+				    size);
+
+		if (copy_from_user(&ustruct, (void __user *)arg, minsz))
+			return -EFAULT;
+
+		if (ustruct.argsz < minsz || ustruct.flags)
+			return -EINVAL;
+
+		return vfio_bind_msi(iommu, ustruct.iova, ustruct.gpa,
+				     ustruct.size);
+	} else if (cmd == VFIO_IOMMU_UNBIND_MSI) {
+		struct vfio_iommu_type1_unbind_msi ustruct;
+
+		minsz = offsetofend(struct vfio_iommu_type1_unbind_msi,
+				    iova);
+
+		if (copy_from_user(&ustruct, (void __user *)arg, minsz))
+			return -EFAULT;
+
+		if (ustruct.argsz < minsz || ustruct.flags)
+			return -EINVAL;
+
+		vfio_unbind_msi(iommu, ustruct.iova);
+		return 0;
 	}
 
 	return -ENOTTY;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 055aa9b9745a..2774a1ab37ae 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -798,6 +798,35 @@ struct vfio_iommu_type1_cache_invalidate {
 };
 #define VFIO_IOMMU_CACHE_INVALIDATE      _IO(VFIO_TYPE, VFIO_BASE + 24)
 
+/**
+ * VFIO_IOMMU_BIND_MSI - _IOWR(VFIO_TYPE, VFIO_BASE + 25,
+ *			struct vfio_iommu_type1_bind_msi)
+ *
+ * Pass a stage 1 MSI doorbell mapping to the host so that this
+ * latter can build a nested stage2 mapping
+ */
+struct vfio_iommu_type1_bind_msi {
+	__u32   argsz;
+	__u32   flags;
+	__u64	iova;
+	__u64	gpa;
+	__u64	size;
+};
+#define VFIO_IOMMU_BIND_MSI      _IO(VFIO_TYPE, VFIO_BASE + 25)
+
+/**
+ * VFIO_IOMMU_UNBIND_MSI - _IOWR(VFIO_TYPE, VFIO_BASE + 26,
+ *			struct vfio_iommu_type1_unbind_msi)
+ *
+ * Unregister an MSI mapping
+ */
+struct vfio_iommu_type1_unbind_msi {
+	__u32   argsz;
+	__u32   flags;
+	__u64	iova;
+};
+#define VFIO_IOMMU_UNBIND_MSI      _IO(VFIO_TYPE, VFIO_BASE + 26)
+
 /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
 
 /*
-- 
2.20.1