[PATCH v4 09/22] 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>

---
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 | 58 +++++++++++++++++++++++++++++++++
 include/uapi/linux/vfio.h       | 29 +++++++++++++++++
 2 files changed, 87 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 12a40b9db6aa..66513679081b 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1710,6 +1710,25 @@ static int vfio_cache_inv_fn(struct device *dev, void *data)
 	return iommu_cache_invalidate(d, dev, &ustruct->info);
 }
 
+static int vfio_bind_msi_fn(struct device *dev, void *data)
+{
+	struct vfio_iommu_type1_bind_msi *ustruct =
+		(struct vfio_iommu_type1_bind_msi *)data;
+	struct iommu_domain *d = iommu_get_domain_for_dev(dev);
+
+	return iommu_bind_guest_msi(d, dev, ustruct->iova,
+				    ustruct->gpa, ustruct->size);
+}
+
+static int vfio_unbind_msi_fn(struct device *dev, void *data)
+{
+	dma_addr_t *iova = (dma_addr_t *)data;
+	struct iommu_domain *d = iommu_get_domain_for_dev(dev);
+
+	iommu_unbind_guest_msi(d, dev, *iova);
+	return 0;
+}
+
 static long vfio_iommu_type1_ioctl(void *iommu_data,
 				   unsigned int cmd, unsigned long arg)
 {
@@ -1814,6 +1833,45 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
 					      vfio_cache_inv_fn);
 		mutex_unlock(&iommu->lock);
 		return ret;
+	} else if (cmd == VFIO_IOMMU_BIND_MSI) {
+		struct vfio_iommu_type1_bind_msi ustruct;
+		int ret;
+
+		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;
+
+		mutex_lock(&iommu->lock);
+		ret = vfio_iommu_for_each_dev(iommu, &ustruct,
+					      vfio_bind_msi_fn);
+		if (ret)
+			vfio_iommu_for_each_dev(iommu, &ustruct.iova,
+						vfio_unbind_msi_fn);
+		mutex_unlock(&iommu->lock);
+		return ret;
+	} else if (cmd == VFIO_IOMMU_UNBIND_MSI) {
+		struct vfio_iommu_type1_unbind_msi ustruct;
+		int ret;
+
+		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;
+
+		mutex_lock(&iommu->lock);
+		ret = vfio_iommu_for_each_dev(iommu, &ustruct.iova,
+					      vfio_unbind_msi_fn);
+		mutex_unlock(&iommu->lock);
+		return ret;
 	}
 
 	return -ENOTTY;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 29f0ef2d805d..6763389b6adc 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -789,6 +789,35 @@ 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