Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 142 insertions, 0 deletions

diff --git a/hw/rdma/vmw/pvrdma_dev_ring.c b/hw/rdma/vmw/pvrdma_dev_ring.c
new file mode 100644
index 000000000..42130667a
--- /dev/null
+++ b/hw/rdma/vmw/pvrdma_dev_ring.c
@@ -0,0 +1,142 @@
+/*
+ * QEMU paravirtual RDMA - Device rings
+ *
+ * Copyright (C) 2018 Oracle
+ * Copyright (C) 2018 Red Hat Inc
+ *
+ * Authors:
+ *     Yuval Shaia <yuval.shaia@oracle.com>
+ *     Marcel Apfelbaum <marcel@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/cutils.h"
+#include "hw/pci/pci.h"
+#include "cpu.h"
+#include "qemu/cutils.h"
+
+#include "trace.h"
+
+#include "../rdma_utils.h"
+#include "pvrdma_dev_ring.h"
+
+int pvrdma_ring_init(PvrdmaRing *ring, const char *name, PCIDevice *dev,
+                     PvrdmaRingState *ring_state, uint32_t max_elems,
+                     size_t elem_sz, dma_addr_t *tbl, uint32_t npages)
+{
+    int i;
+    int rc = 0;
+
+    pstrcpy(ring->name, MAX_RING_NAME_SZ, name);
+    ring->dev = dev;
+    ring->ring_state = ring_state;
+    ring->max_elems = max_elems;
+    ring->elem_sz = elem_sz;
+    /* TODO: Give a moment to think if we want to redo driver settings
+    qatomic_set(&ring->ring_state->prod_tail, 0);
+    qatomic_set(&ring->ring_state->cons_head, 0);
+    */
+    ring->npages = npages;
+    ring->pages = g_malloc0(npages * sizeof(void *));
+
+    for (i = 0; i < npages; i++) {
+        if (!tbl[i]) {
+            rdma_error_report("npages=%d but tbl[%d] is NULL", npages, i);
+            continue;
+        }
+
+        ring->pages[i] = rdma_pci_dma_map(dev, tbl[i], TARGET_PAGE_SIZE);
+        if (!ring->pages[i]) {
+            rc = -ENOMEM;
+            rdma_error_report("Failed to map to page %d in ring %s", i, name);
+            goto out_free;
+        }
+        memset(ring->pages[i], 0, TARGET_PAGE_SIZE);
+    }
+
+    goto out;
+
+out_free:
+    while (i--) {
+        rdma_pci_dma_unmap(dev, ring->pages[i], TARGET_PAGE_SIZE);
+    }
+    g_free(ring->pages);
+
+out:
+    return rc;
+}
+
+void *pvrdma_ring_next_elem_read(PvrdmaRing *ring)
+{
+    unsigned int idx, offset;
+    const uint32_t tail = qatomic_read(&ring->ring_state->prod_tail);
+    const uint32_t head = qatomic_read(&ring->ring_state->cons_head);
+
+    if (tail & ~((ring->max_elems << 1) - 1) ||
+        head & ~((ring->max_elems << 1) - 1) ||
+        tail == head) {
+        trace_pvrdma_ring_next_elem_read_no_data(ring->name);
+        return NULL;
+    }
+
+    idx = head & (ring->max_elems - 1);
+    offset = idx * ring->elem_sz;
+    return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE);
+}
+
+void pvrdma_ring_read_inc(PvrdmaRing *ring)
+{
+    uint32_t idx = qatomic_read(&ring->ring_state->cons_head);
+
+    idx = (idx + 1) & ((ring->max_elems << 1) - 1);
+    qatomic_set(&ring->ring_state->cons_head, idx);
+}
+
+void *pvrdma_ring_next_elem_write(PvrdmaRing *ring)
+{
+    unsigned int idx, offset;
+    const uint32_t tail = qatomic_read(&ring->ring_state->prod_tail);
+    const uint32_t head = qatomic_read(&ring->ring_state->cons_head);
+
+    if (tail & ~((ring->max_elems << 1) - 1) ||
+        head & ~((ring->max_elems << 1) - 1) ||
+        tail == (head ^ ring->max_elems)) {
+        rdma_error_report("CQ is full");
+        return NULL;
+    }
+
+    idx = tail & (ring->max_elems - 1);
+    offset = idx * ring->elem_sz;
+    return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE);
+}
+
+void pvrdma_ring_write_inc(PvrdmaRing *ring)
+{
+    uint32_t idx = qatomic_read(&ring->ring_state->prod_tail);
+
+    idx = (idx + 1) & ((ring->max_elems << 1) - 1);
+    qatomic_set(&ring->ring_state->prod_tail, idx);
+}
+
+void pvrdma_ring_free(PvrdmaRing *ring)
+{
+    if (!ring) {
+        return;
+    }
+
+    if (!ring->pages) {
+        return;
+    }
+
+    while (ring->npages--) {
+        rdma_pci_dma_unmap(ring->dev, ring->pages[ring->npages],
+                           TARGET_PAGE_SIZE);
+    }
+
+    g_free(ring->pages);
+    ring->pages = NULL;
+}