[dpdk-dev] [PATCH v6 1/3] vhost: translate incoming log address to gpa

[Adrian Moreno <amorenoz@redhat.com>]

When IOMMU is enabled the incoming log address is in IOVA space. In that
case, look in IOTLB table and translate the resulting HVA to GPA.

If IOMMU is not enabled, the incoming log address is already a GPA so no
transformation is needed.

Fixes: 69c90e98f483 ("vhost: enable IOMMU support")
Cc: maxime.coquelin@redhat.com
Cc: stable@dpdk.org
Signed-off-by: Adrian Moreno <amorenoz@redhat.com>

---
v6 changes: use PRIx64 macro to fix UB1604-32 build
v5 changes: Rebase on top of dpdk-next-virtio
---
 lib/librte_vhost/vhost.c      |  1 +
 lib/librte_vhost/vhost.h      | 20 +++++++++++++++++
 lib/librte_vhost/vhost_user.c | 42 ++++++++++++++++++++++++++++++++++-
 3 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
index cea44df8c..76e753475 100644
--- a/lib/librte_vhost/vhost.c
+++ b/lib/librte_vhost/vhost.c
@@ -382,6 +382,7 @@ vring_invalidate(struct virtio_net *dev, struct vhost_virtqueue *vq)
 	vq->desc = NULL;
 	vq->avail = NULL;
 	vq->used = NULL;
+	vq->log_guest_addr = 0;
 
 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 		vhost_user_iotlb_wr_unlock(vq);
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 5131a97a3..5e9e7f09d 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -447,6 +447,26 @@ gpa_to_hpa(struct virtio_net *dev, uint64_t gpa, uint64_t size)
 	return 0;
 }
 
+static __rte_always_inline uint64_t
+hva_to_gpa(struct virtio_net *dev, uint64_t vva, uint64_t len)
+{
+	struct rte_vhost_mem_region *r;
+	uint32_t i;
+
+	if (unlikely(!dev || !dev->mem))
+		return 0;
+
+	for (i = 0; i < dev->mem->nregions; i++) {
+		r = &dev->mem->regions[i];
+
+		if (vva >= r->host_user_addr &&
+		    vva + len <  r->host_user_addr + r->size) {
+			return r->guest_phys_addr + vva - r->host_user_addr;
+		}
+	}
+	return 0;
+}
+
 static __rte_always_inline struct virtio_net *
 get_device(int vid)
 {
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index ce4e9fb32..5ae561e55 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -575,6 +575,39 @@ ring_addr_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	return qva_to_vva(dev, ra, size);
 }
 
+/*
+ * Converts vring log address to GPA
+ * If IOMMU is enabled, the log address is IOVA
+ * If IOMMU not enabled, the log address is already GPA
+ */
+static uint64_t
+translate_log_addr(struct virtio_net *dev, struct vhost_virtqueue *vq,
+		uint64_t log_addr)
+{
+	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) {
+		const uint64_t exp_size = sizeof(struct vring_used) +
+			sizeof(struct vring_used_elem) * vq->size;
+		uint64_t hva, gpa;
+		uint64_t size = exp_size;
+
+		hva = vhost_iova_to_vva(dev, vq, log_addr,
+					&size, VHOST_ACCESS_RW);
+		if (size != exp_size)
+			return 0;
+
+		gpa = hva_to_gpa(dev, hva, exp_size);
+		if (!gpa) {
+			RTE_LOG(ERR, VHOST_CONFIG,
+				"VQ: Failed to find GPA for log_addr: 0x%" PRIx64 " hva: 0x%" PRIx64 "\n",
+				log_addr, hva);
+			return 0;
+		}
+		return gpa;
+
+	} else
+		return log_addr;
+}
+
 static struct virtio_net *
 translate_ring_addresses(struct virtio_net *dev, int vq_index)
 {
@@ -682,7 +715,14 @@ translate_ring_addresses(struct virtio_net *dev, int vq_index)
 		vq->last_avail_idx = vq->used->idx;
 	}
 
-	vq->log_guest_addr = addr->log_guest_addr;
+	vq->log_guest_addr =
+		translate_log_addr(dev, vq, addr->log_guest_addr);
+	if (vq->log_guest_addr == 0) {
+		RTE_LOG(DEBUG, VHOST_CONFIG,
+			"(%d) failed to map log_guest_addr .\n",
+			dev->vid);
+		return dev;
+	}
 	vq->access_ok = 1;
 
 	VHOST_LOG_DEBUG(VHOST_CONFIG, "(%d) mapped address desc: %p\n",
-- 
2.21.0