From ba7d8515c1e929baccea9f53d06d131fd2b007a1 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Sun, 3 Mar 2013 10:21:32 -0700 Subject: [PATCH] pci: Teach PCI Bridges about VGA routing 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. Unfortunately with VGA Enable, which we formerly allowed but didn't back, comes along some required VGA baggage. VGA Palette Snooping is required, along with VGA 16-bit decoding. We don't yet have support for palette snooping. We also don't have support for 10-bit VGA aliases, the default mode, but we enable the register, even on root ports, to avoid confusing guests. Fortunately there's likely nothing from this century that requires these features, so the missing bits are noted with TODOs. Signed-off-by: Alex Williamson Signed-off-by: Michael S. Tsirkin --- hw/pci/pci.c | 4 ++++ hw/pci/pci_bridge.c | 44 ++++++++++++++++++++++++++++++++++++++++++-- hw/pci/pci_bus.h | 7 +++++++ hw/pci/pcie_port.c | 2 ++ 4 files changed, 55 insertions(+), 2 deletions(-) diff --git a/hw/pci/pci.c b/hw/pci/pci.c index ed43111bce6a..a88160236e1c 100644 --- a/hw/pci/pci.c +++ b/hw/pci/pci.c @@ -674,6 +674,10 @@ static void pci_init_mask_bridge(PCIDevice *d) #define PCI_BRIDGE_CTL_SEC_DISCARD 0x200 /* Secondary discard timer */ #define PCI_BRIDGE_CTL_DISCARD_STATUS 0x400 /* Discard timer status */ #define PCI_BRIDGE_CTL_DISCARD_SERR 0x800 /* Discard timer SERR# enable */ +/* + * TODO: Bridges default to 10-bit VGA decoding but we currently only + * implement 16-bit decoding (no alias support). + */ pci_set_word(d->wmask + PCI_BRIDGE_CONTROL, PCI_BRIDGE_CTL_PARITY | PCI_BRIDGE_CTL_SERR | diff --git a/hw/pci/pci_bridge.c b/hw/pci/pci_bridge.c index 995842a72d04..edb8c8d9c9ed 100644 --- a/hw/pci/pci_bridge.c +++ b/hw/pci/pci_bridge.c @@ -151,6 +151,28 @@ 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, + MemoryRegion *alias_vga) +{ + uint16_t brctl = pci_get_word(br->dev.config + PCI_BRIDGE_CONTROL); + + memory_region_init_alias(&alias_vga[QEMU_PCI_VGA_IO_LO], + "pci_bridge_vga_io_lo", &br->address_space_io, + QEMU_PCI_VGA_IO_LO_BASE, QEMU_PCI_VGA_IO_LO_SIZE); + memory_region_init_alias(&alias_vga[QEMU_PCI_VGA_IO_HI], + "pci_bridge_vga_io_hi", &br->address_space_io, + QEMU_PCI_VGA_IO_HI_BASE, QEMU_PCI_VGA_IO_HI_SIZE); + memory_region_init_alias(&alias_vga[QEMU_PCI_VGA_MEM], + "pci_bridge_vga_mem", &br->address_space_mem, + QEMU_PCI_VGA_MEM_BASE, QEMU_PCI_VGA_MEM_SIZE); + + if (brctl & PCI_BRIDGE_CTL_VGA) { + pci_register_vga(&br->dev, &alias_vga[QEMU_PCI_VGA_MEM], + &alias_vga[QEMU_PCI_VGA_IO_LO], + &alias_vga[QEMU_PCI_VGA_IO_HI]); + } +} + static PCIBridgeWindows *pci_bridge_region_init(PCIBridge *br) { PCIBus *parent = br->dev.bus; @@ -175,7 +197,8 @@ 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->alias_vga); return w; } @@ -187,6 +210,7 @@ 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); + pci_unregister_vga(&br->dev); } static void pci_bridge_region_cleanup(PCIBridge *br, PCIBridgeWindows *w) @@ -194,6 +218,9 @@ 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->alias_vga[QEMU_PCI_VGA_IO_LO]); + memory_region_destroy(&w->alias_vga[QEMU_PCI_VGA_IO_HI]); + memory_region_destroy(&w->alias_vga[QEMU_PCI_VGA_MEM]); g_free(w); } @@ -227,7 +254,10 @@ 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, 2)) { pci_bridge_update_mappings(s); } @@ -306,6 +336,16 @@ int pci_bridge_initfn(PCIDevice *dev) pci_word_test_and_set_mask(dev->config + PCI_STATUS, PCI_STATUS_66MHZ | PCI_STATUS_FAST_BACK); + + /* + * TODO: We implement VGA Enable in the Bridge Control Register + * therefore per the PCI to PCI bridge spec we must also implement + * VGA Palette Snooping. When done, set this bit writable: + * + * pci_word_test_and_set_mask(dev->wmask + PCI_COMMAND, + * PCI_COMMAND_VGA_PALETTE); + */ + pci_config_set_class(dev->config, PCI_CLASS_BRIDGE_PCI); dev->config[PCI_HEADER_TYPE] = (dev->config[PCI_HEADER_TYPE] & PCI_HEADER_TYPE_MULTI_FUNCTION) | diff --git a/hw/pci/pci_bus.h b/hw/pci/pci_bus.h index f905b9e11e11..aef559ae1f18 100644 --- a/hw/pci/pci_bus.h +++ b/hw/pci/pci_bus.h @@ -47,6 +47,13 @@ struct PCIBridgeWindows { MemoryRegion alias_pref_mem; MemoryRegion alias_mem; MemoryRegion alias_io; + /* + * When bridge control VGA forwarding is enabled, bridges will + * provide positive decode on the PCI VGA defined I/O port and + * MMIO ranges. When enabled forwarding is only qualified on the + * I/O and memory enable bits in the bridge command register. + */ + MemoryRegion alias_vga[QEMU_PCI_VGA_NUM_REGIONS]; }; struct PCIBridge { diff --git a/hw/pci/pcie_port.c b/hw/pci/pcie_port.c index 33a6b0a08ac0..1be107b0c97d 100644 --- a/hw/pci/pcie_port.c +++ b/hw/pci/pcie_port.c @@ -28,10 +28,12 @@ void pcie_port_init_reg(PCIDevice *d) pci_set_word(d->config + PCI_SEC_STATUS, 0); /* Unlike conventional pci bridge, some bits are hardwired to 0. */ +#define PCI_BRIDGE_CTL_VGA_16BIT 0x10 /* VGA 16-bit decode */ pci_set_word(d->wmask + PCI_BRIDGE_CONTROL, PCI_BRIDGE_CTL_PARITY | PCI_BRIDGE_CTL_ISA | PCI_BRIDGE_CTL_VGA | + PCI_BRIDGE_CTL_VGA_16BIT | /* Req, but no alias support yet */ PCI_BRIDGE_CTL_SERR | PCI_BRIDGE_CTL_BUS_RESET); }