netdev - [PATCH v2] vhost/vdpa: Add MSI translation tables to iommu for software-managed MSI

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Message-ID: <20230207120843.1580403-1-sunnanyong@huawei.com>
Date:   Tue, 7 Feb 2023 20:08:43 +0800
From:   Nanyong Sun <sunnanyong@...wei.com>
To:     <joro@...tes.org>, <will@...nel.org>, <robin.murphy@....com>,
        <mst@...hat.com>, <jasowang@...hat.com>
CC:     <iommu@...ts.linux.dev>, <linux-kernel@...r.kernel.org>,
        <kvm@...r.kernel.org>, <virtualization@...ts.linux-foundation.org>,
        <netdev@...r.kernel.org>, <sunnanyong@...wei.com>,
        <wangrong68@...wei.com>
Subject: [PATCH v2] vhost/vdpa: Add MSI translation tables to iommu for software-managed MSI

From: Rong Wang <wangrong68@...wei.com>

Once enable iommu domain for one device, the MSI
translation tables have to be there for software-managed MSI.
Otherwise, platform with software-managed MSI without an
irq bypass function, can not get a correct memory write event
from pcie, will not get irqs.
The solution is to obtain the MSI phy base address from
iommu reserved region, and set it to iommu MSI cookie,
then translation tables will be created while request irq.

Change log
----------

v1->v2:
- add resv iotlb to avoid overlap mapping.

Signed-off-by: Rong Wang <wangrong68@...wei.com>
Signed-off-by: Nanyong Sun <sunnanyong@...wei.com>
---
 drivers/iommu/iommu.c |  1 +
 drivers/vhost/vdpa.c  | 59 ++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 57 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 5f6a85aea501..af9c064ad8b2 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2623,6 +2623,7 @@ void iommu_get_resv_regions(struct device *dev, struct list_head *list)
 	if (ops->get_resv_regions)
 		ops->get_resv_regions(dev, list);
 }
+EXPORT_SYMBOL(iommu_get_resv_regions);
 
 /**
  * iommu_put_resv_regions - release resered regions
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index ec32f785dfde..a58979da8acd 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -49,6 +49,7 @@ struct vhost_vdpa {
 	struct completion completion;
 	struct vdpa_device *vdpa;
 	struct hlist_head as[VHOST_VDPA_IOTLB_BUCKETS];
+	struct vhost_iotlb resv_iotlb;
 	struct device dev;
 	struct cdev cdev;
 	atomic_t opened;
@@ -216,6 +217,8 @@ static int vhost_vdpa_reset(struct vhost_vdpa *v)
 
 	v->in_batch = 0;
 
+	vhost_iotlb_reset(&v->resv_iotlb);
+
 	return vdpa_reset(vdpa);
 }
 
@@ -1013,6 +1016,10 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
 	    msg->iova + msg->size - 1 > v->range.last)
 		return -EINVAL;
 
+	if (vhost_iotlb_itree_first(&v->resv_iotlb, msg->iova,
+					msg->iova + msg->size - 1))
+		return -EINVAL;
+
 	if (vhost_iotlb_itree_first(iotlb, msg->iova,
 				    msg->iova + msg->size - 1))
 		return -EEXIST;
@@ -1103,6 +1110,45 @@ static ssize_t vhost_vdpa_chr_write_iter(struct kiocb *iocb,
 	return vhost_chr_write_iter(dev, from);
 }
 
+static int vhost_vdpa_resv_iommu_region(struct iommu_domain *domain, struct device *dma_dev,
+	struct vhost_iotlb *resv_iotlb)
+{
+	struct list_head dev_resv_regions;
+	phys_addr_t resv_msi_base = 0;
+	struct iommu_resv_region *region;
+	int ret = 0;
+	bool with_sw_msi = false;
+	bool with_hw_msi = false;
+
+	INIT_LIST_HEAD(&dev_resv_regions);
+	iommu_get_resv_regions(dma_dev, &dev_resv_regions);
+
+	list_for_each_entry(region, &dev_resv_regions, list) {
+		ret = vhost_iotlb_add_range_ctx(resv_iotlb, region->start,
+				region->start + region->length - 1,
+				0, 0, NULL);
+		if (ret) {
+			vhost_iotlb_reset(resv_iotlb);
+			break;
+		}
+
+		if (region->type == IOMMU_RESV_MSI)
+			with_hw_msi = true;
+
+		if (region->type == IOMMU_RESV_SW_MSI) {
+			resv_msi_base = region->start;
+			with_sw_msi = true;
+		}
+	}
+
+	if (!ret && !with_hw_msi && with_sw_msi)
+		ret = iommu_get_msi_cookie(domain, resv_msi_base);
+
+	iommu_put_resv_regions(dma_dev, &dev_resv_regions);
+
+	return ret;
+}
+
 static int vhost_vdpa_alloc_domain(struct vhost_vdpa *v)
 {
 	struct vdpa_device *vdpa = v->vdpa;
@@ -1128,11 +1174,16 @@ static int vhost_vdpa_alloc_domain(struct vhost_vdpa *v)
 
 	ret = iommu_attach_device(v->domain, dma_dev);
 	if (ret)
-		goto err_attach;
+		goto err_alloc_domain;
 
-	return 0;
+	ret = vhost_vdpa_resv_iommu_region(v->domain, dma_dev, &v->resv_iotlb);
+	if (ret)
+		goto err_attach_device;
 
-err_attach:
+	return 0;
+err_attach_device:
+	iommu_detach_device(v->domain, dma_dev);
+err_alloc_domain:
 	iommu_domain_free(v->domain);
 	return ret;
 }
@@ -1385,6 +1436,8 @@ static int vhost_vdpa_probe(struct vdpa_device *vdpa)
 		goto err;
 	}
 
+	vhost_iotlb_init(&v->resv_iotlb, 0, 0);
+
 	r = dev_set_name(&v->dev, "vhost-vdpa-%u", minor);
 	if (r)
 		goto err;
-- 
2.25.1