Each PCI Bridge has a set of implied VGA regions that are enabled
when the VGA bit is set in the bridge control register. This allows
VGA devices behind bridges.
Signed-off-by: Alex Williamson <alex.william...@redhat.com>
---
hw/pci/pci_bridge.c | 47 ++++++++++++++++++++++++++++++++++++++++++++---
hw/pci/pci_bus.h | 15 +++++++++++++++
2 files changed, 59 insertions(+), 3 deletions(-)
diff --git a/hw/pci/pci_bridge.c b/hw/pci/pci_bridge.c
index 995842a..42cbfd1 100644
--- a/hw/pci/pci_bridge.c
+++ b/hw/pci/pci_bridge.c
@@ -151,6 +151,37 @@ static void pci_bridge_init_alias(PCIBridge *bridge,
MemoryRegion *alias,
memory_region_add_subregion_overlap(parent_space, base, alias, 1);
}
+static void pci_bridge_init_vga_aliases(PCIBridge *br, PCIBus *parent,
+ PCIBridgeVgaWindows *vga)
+{
+ uint16_t cmd = pci_get_word(br->dev.config + PCI_COMMAND);
+ uint8_t brctl = pci_get_byte(br->dev.config + PCI_BRIDGE_CONTROL);
+
+ memory_region_init_alias(&vga->alias_io_lo, "pci_bridge_vga_io_lo",
+ &br->address_space_io, 0x3b0, 0xc);
+ memory_region_add_subregion_overlap(parent->address_space_io, 0x3b0,
+ &vga->alias_io_lo, 1);
+
+ memory_region_init_alias(&vga->alias_io_hi, "pci_bridge_vga_io_hi",
+ &br->address_space_io, 0x3c0, 0x20);
+ memory_region_add_subregion_overlap(parent->address_space_io, 0x3c0,
+ &vga->alias_io_hi, 1);
+
+ if (!(cmd & PCI_COMMAND_IO) || !(brctl & PCI_BRIDGE_CTL_VGA)) {
+ memory_region_set_enabled(&vga->alias_io_lo, false);
+ memory_region_set_enabled(&vga->alias_io_hi, false);
+ }
+
+ memory_region_init_alias(&vga->alias_mem, "pci_bridge_vga_mem",
+ &br->address_space_mem, 0xa0000, 0x20000);
+ memory_region_add_subregion_overlap(parent->address_space_mem, 0xa0000,
+ &vga->alias_mem, 1);
+
+ if (!(cmd & PCI_COMMAND_MEMORY) || !(brctl & PCI_BRIDGE_CTL_VGA)) {
+ memory_region_set_enabled(&vga->alias_mem, false);
+ }
+}
+
static PCIBridgeWindows *pci_bridge_region_init(PCIBridge *br)
{
PCIBus *parent = br->dev.bus;
@@ -175,7 +206,8 @@ static PCIBridgeWindows *pci_bridge_region_init(PCIBridge
*br)
&br->address_space_io,
parent->address_space_io,
cmd & PCI_COMMAND_IO);
- /* TODO: optinal VGA and VGA palette snooping support. */
+
+ pci_bridge_init_vga_aliases(br, parent, &w->vga);
return w;
}
@@ -187,6 +219,9 @@ static void pci_bridge_region_del(PCIBridge *br,
PCIBridgeWindows *w)
memory_region_del_subregion(parent->address_space_io, &w->alias_io);
memory_region_del_subregion(parent->address_space_mem, &w->alias_mem);
memory_region_del_subregion(parent->address_space_mem, &w->alias_pref_mem);
+ memory_region_del_subregion(parent->address_space_io, &w->vga.alias_io_lo);
+ memory_region_del_subregion(parent->address_space_io, &w->vga.alias_io_hi);
+ memory_region_del_subregion(parent->address_space_mem, &w->vga.alias_mem);
}
static void pci_bridge_region_cleanup(PCIBridge *br, PCIBridgeWindows *w)
@@ -194,6 +229,9 @@ static void pci_bridge_region_cleanup(PCIBridge *br,
PCIBridgeWindows *w)
memory_region_destroy(&w->alias_io);
memory_region_destroy(&w->alias_mem);
memory_region_destroy(&w->alias_pref_mem);
+ memory_region_destroy(&w->vga.alias_io_lo);
+ memory_region_destroy(&w->vga.alias_io_hi);
+ memory_region_destroy(&w->vga.alias_mem);
g_free(w);
}
@@ -227,7 +265,10 @@ void pci_bridge_write_config(PCIDevice *d,
/* memory base/limit, prefetchable base/limit and
io base/limit upper 16 */
- ranges_overlap(address, len, PCI_MEMORY_BASE, 20)) {
+ ranges_overlap(address, len, PCI_MEMORY_BASE, 20) ||
+
+ /* vga enable */
+ ranges_overlap(address, len, PCI_BRIDGE_CONTROL, 1)) {
pci_bridge_update_mappings(s);
}
@@ -294,7 +335,7 @@ void pci_bridge_reset(DeviceState *qdev)
pci_set_long(conf + PCI_PREF_BASE_UPPER32, 0);
pci_set_long(conf + PCI_PREF_LIMIT_UPPER32, 0);
- pci_set_word(conf + PCI_BRIDGE_CONTROL, 0);
+ pci_set_byte(conf + PCI_BRIDGE_CONTROL, 0);
}
/* default qdev initialization function for PCI-to-PCI bridge */
diff --git a/hw/pci/pci_bus.h b/hw/pci/pci_bus.h
index f905b9e..60d5378 100644
--- a/hw/pci/pci_bus.h
+++ b/hw/pci/pci_bus.h
@@ -36,6 +36,20 @@ struct PCIBus {
int *irq_count;
};
+typedef struct PCIBridgeVgaWindows PCIBridgeVgaWindows;
+
+/*
+ * When bridge control VGA forwarding is enabled, bridges will provide
+ * positive decode on the PCI VGA defined I/O port and MMIO ranges noted
+ * below. When set, forwarding is only qualified on the I/O and memory
+ * enable bits in the bridge command register.
+ */
+struct PCIBridgeVgaWindows {
+ MemoryRegion alias_io_lo; /* I/O ports 0x3b0 - 0x3bb */
+ MemoryRegion alias_io_hi; /* I/O ports 0x3c0 - 0x3df */
+ MemoryRegion alias_mem; /* MMIO 0xa0000 - 0xbffff */
+};
+
typedef struct PCIBridgeWindows PCIBridgeWindows;
/*
@@ -47,6 +61,7 @@ struct PCIBridgeWindows {
MemoryRegion alias_pref_mem;
MemoryRegion alias_mem;
MemoryRegion alias_io;
+ PCIBridgeVgaWindows vga;
};
struct PCIBridge {
