msix: Add simple BAR allocation MSIX setup functions

msi_init() takes over a BAR without really specifying or allowing
specification of how it does so.  Instead, let's split it into
two interfaces, one fully specified, and one trivially easy.  This
implements the latter.  msix_init_exclusive_bar() takes over
allocating and filling a PCI BAR _exclusively_ for the use of MSIX.
When used, the matching msi_uninit_exclusive_bar() should be used
to tear it down.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/msix.c b/hw/msix.c
index b64f1093265492c5c4164ab04e3768036213743c..bafea94084c59a6af6fe92f54c6621531697ea78 100644 (file)
--- a/hw/msix.c
+++ b/hw/msix.c
@@ -299,6 +299,45 @@ err_config:
     return ret;
 }
 
+int msix_init_exclusive_bar(PCIDevice *dev, unsigned short nentries,
+                            uint8_t bar_nr)
+{
+    int ret;
+    char *name;
+
+    /*
+     * 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_PBA_OFFSET (MSIX_EXCLUSIVE_BAR_SIZE / 2)
+
+    if (nentries * PCI_MSIX_ENTRY_SIZE > MSIX_EXCLUSIVE_BAR_PBA_OFFSET) {
+        return -EINVAL;
+    }
+
+    if (asprintf(&name, "%s-msix", dev->name) == -1) {
+        return -ENOMEM;
+    }
+
+    memory_region_init(&dev->msix_exclusive_bar, name, MSIX_EXCLUSIVE_BAR_SIZE);
+
+    free(name);
+
+    ret = msix_init(dev, nentries, &dev->msix_exclusive_bar, bar_nr,
+                    MSIX_EXCLUSIVE_BAR_SIZE);
+    if (ret) {
+        memory_region_destroy(&dev->msix_exclusive_bar);
+        return ret;
+    }
+
+    pci_register_bar(dev, bar_nr, PCI_BASE_ADDRESS_SPACE_MEMORY,
+                     &dev->msix_exclusive_bar);
+
+    return 0;
+}
+
 static void msix_free_irq_entries(PCIDevice *dev)
 {
     int vector;
@@ -329,6 +368,14 @@ int msix_uninit(PCIDevice *dev, MemoryRegion *bar)
     return 0;
 }
 
+void msix_uninit_exclusive_bar(PCIDevice *dev)
+{
+    if (msix_present(dev)) {
+        msix_uninit(dev, &dev->msix_exclusive_bar);
+        memory_region_destroy(&dev->msix_exclusive_bar);
+    }
+}
+
 void msix_save(PCIDevice *dev, QEMUFile *f)
 {
     unsigned n = dev->msix_entries_nr;

diff --git a/hw/msix.h b/hw/msix.h
index 4a17f945408799215050db59e955082d5d1497fc..f681bb0855db74ed920a255c3e3f437e58749b10 100644 (file)
--- a/hw/msix.h
+++ b/hw/msix.h
@@ -7,10 +7,13 @@
 int msix_init(PCIDevice *pdev, unsigned short nentries,
               MemoryRegion *bar,
               unsigned bar_nr, unsigned bar_size);
+int msix_init_exclusive_bar(PCIDevice *dev, unsigned short nentries,
+                            uint8_t bar_nr);
 
 void msix_write_config(PCIDevice *dev, uint32_t address, uint32_t val, int len);
 
 int msix_uninit(PCIDevice *d, MemoryRegion *bar);
+void msix_uninit_exclusive_bar(PCIDevice *dev);
 
 unsigned int msix_nr_vectors_allocated(const PCIDevice *dev);
 

diff --git a/hw/pci.h b/hw/pci.h
index 3d534e77aefc6cf7d9a3d15da15b8138d9b49611..7344891706507bb8c74c2606f6172fdefbc43b85 100644 (file)
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -222,6 +222,8 @@ struct PCIDevice {
 
     /* Space to store MSIX table */
     uint8_t *msix_table_page;
+    /* MemoryRegion container for msix exclusive BAR setup */
+    MemoryRegion msix_exclusive_bar;
     /* MMIO index used to map MSIX table and pending bit entries. */
     MemoryRegion msix_mmio;
     /* Reference-count for entries actually in use by driver. */