[Qemu-devel] [PATCH 4/5] pci: remove hard-coded bar size in msix_init_exclusive_bar()

[Jason Wang <jasowang@redhat.com>]

Let msix_init_exclusive_bar() can accept bar_size parameter other than
a hard-coded limit 4096. Then caller can specify a bar_size depends on
msix entries and can use up to 2048 msix entries as PCI spec
allows. To keep migration compatibility, 4096 is used for all callers
and pba were start from half of bar size.

Cc: Keith Busch <keith.busch@intel.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Anthony Liguori <aliguori@amazon.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/block/nvme.c        |  2 +-
 hw/misc/ivshmem.c      |  2 +-
 hw/pci/msix.c          | 18 +++++++-----------
 hw/virtio/virtio-pci.c |  2 +-
 include/hw/pci/msix.h  |  2 +-
 5 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index ce079ae..0fa1396 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -786,7 +786,7 @@ static int nvme_init(PCIDevice *pci_dev)
     pci_register_bar(&n->parent_obj, 0,
         PCI_BASE_ADDRESS_SPACE_MEMORY | PCI_BASE_ADDRESS_MEM_TYPE_64,
         &n->iomem);
-    msix_init_exclusive_bar(&n->parent_obj, n->num_queues, 4);
+    msix_init_exclusive_bar(&n->parent_obj, n->num_queues, 4, 4096);
 
     id->vid = cpu_to_le16(pci_get_word(pci_conf + PCI_VENDOR_ID));
     id->ssvid = cpu_to_le16(pci_get_word(pci_conf + PCI_SUBSYSTEM_VENDOR_ID));
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index 5d272c8..3e2a2d4 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -631,7 +631,7 @@ static uint64_t ivshmem_get_size(IVShmemState * s) {
 
 static void ivshmem_setup_msi(IVShmemState * s)
 {
-    if (msix_init_exclusive_bar(PCI_DEVICE(s), s->vectors, 1)) {
+    if (msix_init_exclusive_bar(PCI_DEVICE(s), s->vectors, 1, 4096)) {
         IVSHMEM_DPRINTF("msix initialization failed\n");
         exit(1);
     }
diff --git a/hw/pci/msix.c b/hw/pci/msix.c
index 24de260..9a1894f 100644
--- a/hw/pci/msix.c
+++ b/hw/pci/msix.c
@@ -291,33 +291,29 @@ int msix_init(struct PCIDevice *dev, unsigned short nentries,
 }
 
 int msix_init_exclusive_bar(PCIDevice *dev, unsigned short nentries,
-                            uint8_t bar_nr)
+                            uint8_t bar_nr, uint32_t bar_size)
 {
     int ret;
     char *name;
+    uint32_t bar_pba_offset = bar_size / 2;
 
     /*
      * Migration compatibility dictates that this remains a 4k
      * BAR with the vector table in the lower half and PBA in
      * the upper half.  Do not use these elsewhere!
      */
-#define MSIX_EXCLUSIVE_BAR_SIZE 4096
-#define MSIX_EXCLUSIVE_BAR_TABLE_OFFSET 0
-#define MSIX_EXCLUSIVE_BAR_PBA_OFFSET (MSIX_EXCLUSIVE_BAR_SIZE / 2)
-#define MSIX_EXCLUSIVE_CAP_OFFSET 0
-
-    if (nentries * PCI_MSIX_ENTRY_SIZE > MSIX_EXCLUSIVE_BAR_PBA_OFFSET) {
+    if (nentries * PCI_MSIX_ENTRY_SIZE > bar_pba_offset) {
         return -EINVAL;
     }
 
     name = g_strdup_printf("%s-msix", dev->name);
-    memory_region_init(&dev->msix_exclusive_bar, OBJECT(dev), name, MSIX_EXCLUSIVE_BAR_SIZE);
+    memory_region_init(&dev->msix_exclusive_bar, OBJECT(dev), name, bar_size);
     g_free(name);
 
     ret = msix_init(dev, nentries, &dev->msix_exclusive_bar, bar_nr,
-                    MSIX_EXCLUSIVE_BAR_TABLE_OFFSET, &dev->msix_exclusive_bar,
-                    bar_nr, MSIX_EXCLUSIVE_BAR_PBA_OFFSET,
-                    MSIX_EXCLUSIVE_CAP_OFFSET);
+                    0, &dev->msix_exclusive_bar,
+                    bar_nr, bar_pba_offset,
+                    0);
     if (ret) {
         return ret;
     }
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index abaefaa..616d3be 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -973,7 +973,7 @@ static void virtio_pci_device_plugged(DeviceState *d)
     config[PCI_INTERRUPT_PIN] = 1;
 
     if (proxy->nvectors &&
-        msix_init_exclusive_bar(&proxy->pci_dev, proxy->nvectors, 1)) {
+        msix_init_exclusive_bar(&proxy->pci_dev, proxy->nvectors, 1, 4096)) {
         error_report("unable to init msix vectors to %" PRIu32,
                      proxy->nvectors);
         proxy->nvectors = 0;
diff --git a/include/hw/pci/msix.h b/include/hw/pci/msix.h
index 954d82b..43edebc 100644
--- a/include/hw/pci/msix.h
+++ b/include/hw/pci/msix.h
@@ -11,7 +11,7 @@ int msix_init(PCIDevice *dev, unsigned short nentries,
               unsigned table_offset, MemoryRegion *pba_bar,
               uint8_t pba_bar_nr, unsigned pba_offset, uint8_t cap_pos);
 int msix_init_exclusive_bar(PCIDevice *dev, unsigned short nentries,
-                            uint8_t bar_nr);
+                            uint8_t bar_nr, uint32_t bar_size);
 
 void msix_write_config(PCIDevice *dev, uint32_t address, uint32_t val, int len);
 
-- 
1.9.1