Re: [OpenBIOS] [PATCH] pci: fix BAR setup

[Blue Swirl]

On Fri, Apr 19, 2013 at 9:10 PM, Artyom Tarasenko  wrote:
> On Mon, May 14, 2012 at 8:58 PM, Blue Swirl  wrote:
> > On Mon, May 14, 2012 at 1:49 PM, Mark Cave-Ayland
> >  wrote:
> > > On 14/05/12 14:28, Artyom Tarasenko wrote:
> > > > > > It's to avoid VGA legacy mapping at 0xa0000. If I change
> > > > > > hwdefs.pci.pci_mem_base in arch/sparc64/openbios.c to 0, OpenBIOS will
> > > > > > crash during VGA init. Previously this worked because the PCI devices
> > > > > > were mapped somewhat randomly and by chance, VGA legacy low mem area
> > > > > > was avoided.
> > > > > >
> > > > > > I think the correct fix is to make QEMU VGA device disable the legacy
> > > > > > mapping unless explicitly enabled. Alternatively the child base
> > > > > > arithmetic could be fixed in OpenBIOS like proposed by Jakub.
> > > > >
> > > > > Did a patch ever come out of this discussion in the end?
> > > >
> > > > No. :-) Feel free to fix it, unless Blue prefers fixing it himself...
> > >
> > > I'm not sure I'm confident enough with PCI to do this, and I'm also not sure
> > > what Blue's recommended fix actually is? Is it to increase parent_base by
> > > 0x1000 or set child_base to zero?
> >
> > The best solution is to fix VGA (assuming my analysis was right) and
> > set child_base to zero.
>
> Blue, do you know whether the QOMification improved the situation with
> the legacy VGA low mem area?

I don't think it had any effect, but PCI bridging code was fixed recently.

There are still some problems, if I move most devices behind the first
bridge with this patch, Sparc64 does not boot anymore:
diff --git a/hw/sparc64/sun4u.c b/hw/sparc64/sun4u.c
index 0d29620..8bf7230 100644
--- a/hw/sparc64/sun4u.c
+++ b/hw/sparc64/sun4u.c
@@ -813,7 +813,7 @@ static void sun4uv_init(MemoryRegion *address_space_mem,
     M48t59State *nvram;
     unsigned int i;
     uint64_t initrd_addr, initrd_size, kernel_addr, kernel_size, kernel_entry;
-    PCIBus *pci_bus, *pci_bus2, *pci_bus3;
+    PCIBus *pci_bus2, *pci_bus3;
     ISABus *isa_bus;
     qemu_irq *ivec_irqs, *pbm_irqs;
     DriveInfo *hd[MAX_IDE_BUS * MAX_IDE_DEVS];
@@ -829,12 +829,11 @@ static void sun4uv_init(MemoryRegion *address_space_mem,
     prom_init(hwdef->prom_addr, bios_name);

ivec_irqs = qemu_allocate_irqs(cpu_set_ivec_irq, cpu, IVEC_MAX);
-    pci_bus = pci_apb_init(APB_SPECIAL_BASE, APB_MEM_BASE, ivec_irqs,
&pci_bus2,
-                           &pci_bus3, &pbm_irqs);
-    pci_vga_init(pci_bus);
+    pci_apb_init(APB_SPECIAL_BASE, APB_MEM_BASE, ivec_irqs, &pci_bus2,
+                 &pci_bus3, &pbm_irqs);
+    pci_vga_init(pci_bus2);

-    // XXX Should be pci_bus3
-    isa_bus = pci_ebus_init(pci_bus, -1, pbm_irqs);
+    isa_bus = pci_ebus_init(pci_bus2, -1, pbm_irqs);

i = 0;
     if (hwdef->console_serial_base) {
@@ -859,7 +858,7 @@ static void sun4uv_init(MemoryRegion *address_space_mem,

ide_drive_get(hd, MAX_IDE_BUS);

-    pci_cmd646_ide_init(pci_bus, hd, 1);
+    pci_cmd646_ide_init(pci_bus2, hd, 1);

isa_create_simple(isa_bus, "i8042");
     for(i = 0; i < MAX_FD; i++) {

Also ethernet is using the main PCI bus instead of the bridged version:
(qemu) info pci
  Bus  0, device   0, function 0:
    Host bridge: PCI device 108e:a000
      id ""
  Bus  0, device   1, function 0:
    PCI bridge: PCI device 108e:5000
      BUS 0.
      secondary bus 1.
      subordinate bus 255.
      IO range [0x0000, 0x0fff]
      memory range [0x00000000, 0x000fffff]
      prefetchable memory range [0x00000000, 0x000fffff]
      id ""
  Bus  1, device   0, function 0:
    VGA controller: PCI device 1234:1111
      BAR0: 32 bit prefetchable memory at 0x01000000 [0x01ffffff].
      BAR2: 32 bit memory at 0x02000000 [0x02000fff].
      BAR6: 32 bit memory at 0x02010000 [0x0201ffff].
      id ""
  Bus  1, device   1, function 0:
    Bridge: PCI device 108e:1000
      BAR0: 32 bit memory at 0xffffffffffffffff [0x00fffffe].
      BAR1: 32 bit memory at 0xffffffffffffffff [0x007ffffe].
      id ""
  Bus  1, device   2, function 0:
    IDE controller: PCI device 1095:0646
      IRQ 0.
      BAR0: I/O at 0xffffffffffffffff [0x0006].
      BAR1: I/O at 0xffffffffffffffff [0x0002].
      BAR2: I/O at 0xffffffffffffffff [0x0006].
      BAR3: I/O at 0xffffffffffffffff [0x0002].
      BAR4: I/O at 0xffffffffffffffff [0x000e].
      id ""
  Bus  0, device   1, function 1:
    PCI bridge: PCI device 108e:5000
      BUS 0.
      secondary bus 0.
      subordinate bus 0.
      IO range [0x0000, 0x0fff]
      memory range [0x00000000, 0x000fffff]
      prefetchable memory range [0x00000000, 0x000fffff]
      id ""
  Bus  0, device   2, function 0:
^ should be bus 1.

Ethernet controller: PCI device 10ec:8029
      IRQ 0.
      BAR0: I/O at 0xffffffffffffffff [0x00fe].
      BAR6: 32 bit memory at 0xffffffffffffffff [0x0003fffe].
      id ""
> linux/sparc and solaris/sparc under qemu blog:
> http://tyom.blogspot.com/search/label/qemu