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/*
* 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_new0(void *, npages);
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;
}
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