[PATCH-for-10.0,v2,04/13] hw/pci: Introduce PCIBusFlag::PCI_BUS_BAR_AT_ADDR0_REFUSED

Commit Message

Philippe Mathieu-Daudé Nov. 26, 2024, 11:22 a.m. UTC

Some machines need PCI buses to allow access at BAR0.
Introduce the PCI_BUS_BAR_AT_ADDR0_REFUSED flag and the
pci_bus_refuse_bar_at_addr_0() helper. Set the flag in
pci_root_bus_internal_init() where all root buses are
created.

Signed-off-by: Philippe Mathieu-Daudé <[e-mail]>
---
 include/hw/pci/pci_bus.h | 6 ++++++
 hw/pci/pci.c             | 5 ++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

Patch

diff --git a/include/hw/pci/pci_bus.h b/include/hw/pci/pci_bus.h
index 6ecfe2e06d5..6d7bf682e8f 100644
--- a/include/hw/pci/pci_bus.h
+++ b/include/hw/pci/pci_bus.h
@@ -26,6 +26,7 @@  enum PCIBusFlag {
     PCI_BUS_EXTENDED_CONFIG_SPACE                           = 0x0002,
     /* This is a CXL Type BUS */
     PCI_BUS_CXL                                             = 0x0004,
+    PCI_BUS_BAR_AT_ADDR0_REFUSED                            = 0x0008,
 };
 
 #define PCI_NO_PASID UINT32_MAX
@@ -72,4 +73,9 @@  static inline bool pci_bus_allows_extended_config_space(PCIBus *bus)
     return !!(bus->flags & PCI_BUS_EXTENDED_CONFIG_SPACE);
 }
 
+static inline bool pci_bus_refuse_bar_at_addr_0(PCIBus *bus)
+{
+    return !!(bus->flags & PCI_BUS_BAR_AT_ADDR0_REFUSED);
+}
+
 #endif /* QEMU_PCI_BUS_H */
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index e05f8a828bb..27b66583e54 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -537,6 +537,9 @@  static void pci_root_bus_internal_init(PCIBus *bus, DeviceState *parent,
     bus->address_space_mem = mem;
     bus->address_space_io = io;
     bus->flags |= PCI_BUS_IS_ROOT;
+    if (machine_refuses_bar_at_addr_0()) {
+        bus->flags |= PCI_BUS_BAR_AT_ADDR0_REFUSED;
+    }
 
     /* host bridge */
     QLIST_INIT(&bus->child);
@@ -1479,7 +1482,7 @@  pcibus_t pci_bar_address(PCIDevice *d,
 {
     pcibus_t new_addr, last_addr;
     uint16_t cmd = pci_get_word(d->config + PCI_COMMAND);
-    bool bar_at_addr_0_refused = machine_refuses_bar_at_addr_0();
+    bool bar_at_addr_0_refused = pci_bus_refuse_bar_at_addr_0(pci_get_bus(d));
 
     if (type & PCI_BASE_ADDRESS_SPACE_IO) {
         if (!(cmd & PCI_COMMAND_IO)) {