[Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Alexey Korolev]

Hi,

We have got some issues with 64bit PCI devices support under Windows guests.
Windows fails to start any PCI devices with 64bit BARs when size exceeds 
512MB with error code 12 (can't allocate resources). In other words it 
fails when the PCI memory region is located above 4GB.

I tried to investigate this problem and found document from Microsoft:
http://msdn.microsoft.com/en-us/windows/hardware/gg462986

It states that the _DSM method must be implemented to support devices 
above 4GB.

Unfortunately I'm not familiar with ACPI code of seabios, so can't 
implement the _DSM method. May be you have other ideas what needs to be 
done to fix it? Any help is appreciated.

Thanks,
Alexey

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Michael S. Tsirkin]

On Wed, Nov 30, 2011 at 02:04:08PM +1300, Alexey Korolev wrote:
> Hi,
> 
> We have got some issues with 64bit PCI devices support under Windows guests.
> Windows fails to start any PCI devices with 64bit BARs when size
> exceeds 512MB with error code 12 (can't allocate resources). In
> other words it fails when the PCI memory region is located above
> 4GB.
> 
> I tried to investigate this problem and found document from Microsoft:
> http://msdn.microsoft.com/en-us/windows/hardware/gg462986
> 
> It states that the _DSM method must be implemented to support
> devices above 4GB.

That's not how I read it:
	Windows Vista always respects the boot configuration of devices above
	4 GB, considering the processor’s addressing capability and the version
	of the Windows operating system that is running.

> Unfortunately I'm not familiar with ACPI code of seabios, so can't
> implement the _DSM method. May be you have other ideas what needs to
> be done to fix it? Any help is appreciated.
> 
> Thanks,
> Alexey

Could you share some more detail about your setup?

-- 
MST

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Alexey Korolev]

> On Wed, Nov 30, 2011 at 02:04:08PM +1300, Alexey Korolev wrote:
>> Hi,
>>
>> We have got some issues with 64bit PCI devices support under Windows guests.
>> Windows fails to start any PCI devices with 64bit BARs when size
>> exceeds 512MB with error code 12 (can't allocate resources). In
>> other words it fails when the PCI memory region is located above
>> 4GB.
>>
>> I tried to investigate this problem and found document from Microsoft:
>> http://msdn.microsoft.com/en-us/windows/hardware/gg462986
>>
>> It states that the _DSM method must be implemented to support
>> devices above 4GB.
> That's not how I read it:
> 	Windows Vista always respects the boot configuration of devices above
> 	4 GB, considering the processor’s addressing capability and the version
> 	of the Windows operating system that is running.
Well, it's written in a very interesting way. They do recommend to have 
_DSM method in order to support 64bit.
It is quite possible that the source of the problem is somewhere else.

Actually it is also quite interesting to know what is the resource 
window for 440FX? Perhaps Windows OS does not believe that 440FX 
supports 64bit PCI resources. But I see no way to check this.
>> Unfortunately I'm not familiar with ACPI code of seabios, so can't
>> implement the _DSM method. May be you have other ideas what needs to
>> be done to fix it? Any help is appreciated.
>>
>> Thanks,
>> Alexey
> Could you share some more detail about your setup?
>
Ok Here are logs the faulty device is: 00:05.0.
In the first case the BAR1 size is 512MB and it fails in Windows (Linux 
is fine, the kernel enumerates the bus and assigns the resource above 4GB),
In the second case the BAR1 size is 256M and works fine.

The first one causing issues. As PCI memory region for 00.0.5 is not 
assigned after windows boot.  (Note. I also tried to supply a particular 
physical addresses over 4GB in pciinit.c code but this leads to 
completely the same behaviour. Windows just don't pick-up the resource.)


--------------------- Seabios log PCI BAR 512MB: 
------------------------------------

Changing serial settings was 0/0 now 3/0
Start bios (version pre-0.6.3-20111201_162012-core-3000-3.et.endace.com)
enabling shadow ram
qemu_cfg_present=1
Find memory size
Ram Size=0xe0000000 (0x0000000320000000 high)
malloc setup
Relocating init from 0x000e01c0 to 0xdffe0980 (size 62800)
malloc fixup reloc
init ivt
init bda
init pic
init timer
CPU Mhz=2801
math cp init
init mtrr
pci setup
=== PCI bus & bridge init ===
PCI: pci_bios_init_bus_rec bus = 0x0
=== PCI device probing ===
PCI probe
PCI device 00:00.0 (vd=8086:1237 c=0600)
PCI device 00:01.0 (vd=8086:7000 c=0601)
PCI device 00:01.1 (vd=8086:7010 c=0101)
PCI device 00:01.2 (vd=8086:7020 c=0c03)
PCI device 00:01.3 (vd=8086:7113 c=0680)
PCI device 00:02.0 (vd=1013:00b8 c=0300)
PCI device 00:03.0 (vd=10ec:8139 c=0200)
PCI device 00:05.0 (vd=eace:eace c=0280)
PCI device 00:06.0 (vd=1af4:1002 c=0500)
Found 9 PCI devices (max PCI bus is 00)
=== PCI new allocation pass #1 ===
PCI: check devices bus 0
=== PCI new allocation pass #2 ===
PCI: init bases bus 0 (primary)
   type io max 100 sum 150 base c000
     size      100: 1 bar(s),     c000 ->     c0ff
     size       20: 2 bar(s),     c100 ->     c13f
     size       10: 1 bar(s),     c140 ->     c14f
   type mem max 10000 sum 32000 base febc0000
     size    10000: 3 bar(s), febc0000 -> febeffff
     size     1000: 2 bar(s), febf0000 -> febf1fff
   type prefmem max 2000000 sum 2000000 base fc000000
     size  2000000: 1 bar(s), fc000000 -> fdffffff
PCI: map device bus 0, bfd 0x0
PCI: map device bus 0, bfd 0x8
PCI: map device bus 0, bfd 0x9
   bar 4, addr c140, size 10 [io]
PCI: map device bus 0, bfd 0xa
   bar 4, addr c100, size 20 [io]
PCI: map device bus 0, bfd 0xb
PCI: map device bus 0, bfd 0x10
   bar 0, addr fc000000, size 2000000 [mem]
   bar 1, addr febf0000, size 1000 [mem]
   bar 6, addr febc0000, size 10000 [mem]
PCI: map device bus 0, bfd 0x18
   bar 0, addr c000, size 100 [io]
   bar 1, addr febf1000, size 100 [mem]
   bar 6, addr febd0000, size 10000 [mem]
PCI: map device bus 0, bfd 0x28
   bar 0, addr febe0000, size 10000 [mem]
   bar 1, addr 0, size 20000000 [mem]
PCI: map device bus 0, bfd 0x30
   bar 0, addr c120, size 20 [io]
PCI: bus=0 devfn=0x00: vendor_id=0x8086 device_id=0x1237
PCI: bus=0 devfn=0x08: vendor_id=0x8086 device_id=0x7000
PCI: bus=0 devfn=0x09: vendor_id=0x8086 device_id=0x7010
PCI: bus=0 devfn=0x0a: vendor_id=0x8086 device_id=0x7020
PCI: bus=0 devfn=0x0b: vendor_id=0x8086 device_id=0x7113
PCI: bus=0 devfn=0x10: vendor_id=0x1013 device_id=0x00b8
PCI: bus=0 devfn=0x18: vendor_id=0x10ec device_id=0x8139
PCI: bus=0 devfn=0x28: vendor_id=0xeace device_id=0xeace
PCI: bus=0 devfn=0x30: vendor_id=0x1af4 device_id=0x1002
init smm
boot order:
1: /pci@i0cf8/ide@1,1/drive@0/disk@0
2: /pci@i0cf8/ide@1,1/drive@1/disk@0
Found 2 cpu(s) max supported 2 cpu(s)
init bios32
init PMM
init PNPBIOS table
init keyboard
init mouse
init PIR table
init MPTable
MP table addr=0x000fda00 MPC table addr=0x000fda10 size=260
init SMBIOS tables
SMBIOS ptr=0x000fd9e0 table=0x000fd880 size=346
init ACPI tables
ACPI tables: RSDP=0x000fd850 RSDT=0xdfffd740
Scan for VGA option rom
Attempting to init PCI bdf 00:02.0 (vd 1013:00b8)
Copying option rom (size 35840) from 0xfebc0000 to c0000
Running option rom at c000:0003
Turning on vga text mode console
SeaBIOS (version pre-0.6.3-20111201_162012-core-3000-3.et.endace.com)

init usb
UHCI init on dev 00:01.2 (io=c100)
/dffdf000\ Start thread
/dffde000\ Start thread
/dffdd000\ Start thread
\dffdd000/ End thread
init ps2port
/dffdd000\ Start thread
init lpt
Found 0 lpt ports
init serial
Found 1 serial ports
init floppy drives
init hard drives ddr 0
ATA controller 1 at 1f0/3f4/0 (irq 14 dev 9)
/dffdb000\ Start thread
ATA controller 2 at 170/374/0 (irq 15 dev 9)
/dffda000\ Start thread
init ahci
init virtio-blk
|dffdb000| ata0-0: QEMU HARDDISK ATA-7 Hard-Disk (51200 MiBytes)
|dffdb000| Searching bootorder for: /pci@i0cf8/*@1,1/drive@0/disk@0
|dffdb000| Registering bootable: ata0-0: QEMU HARDDISK ATA-7 Hard-Disk 
(51200 MiBytes) (type:2 prio:1 data:fd800)
\dffdb000/ End thread
|dffda000| DVD/CD [ata1-0: QEMU DVD-ROM ATAPI-4 DVD/CD]
|dffda000| Searching bootorder for: /pci@i0cf8/*@1,1/drive@1/disk@0
|dffda000| Registering bootable: DVD/CD [ata1-0: QEMU DVD-ROM ATAPI-4 
DVD/CD] (type:3 prio:2 data:fd7d0)
\dffda000/ End thread
|dffde000| set_address 0xdffe0150
|dffde000| config_usb: 0xdffdccec
|dffde000| device rev=0100 cls=00 sub=00 proto=00 size=08
|dffde000| usb_hid_init 0xdffdccec
\dffde000/ End thread
\dffdf000/ End thread
|dffdd000| PS2 keyboard initialized
\dffdd000/ End thread
All threads complete.
Scan for option roms
Attempting to init PCI bdf 00:00.0 (vd 8086:1237)
Attempting to init PCI bdf 00:01.0 (vd 8086:7000)
Attempting to init PCI bdf 00:01.2 (vd 8086:7020)
Attempting to init PCI bdf 00:01.3 (vd 8086:7113)
Attempting to init PCI bdf 00:03.0 (vd 10ec:8139)
Copying option rom (size 61440) from 0xfebd0000 to c9000
Running option rom at c900:0003
pmm call arg1=1
pmm01: handle=18ae1000
pmm call arg1=0
pmm00: length=f00 handle=18ae1000 flags=2
pmm call arg1=1
pmm01: handle=18ae2004
pmm call arg1=0
pmm00: length=4000 handle=18ae2004 flags=2
Attempting to init PCI bdf 00:05.0 (vd eace:eace)
Attempting to init PCI bdf 00:06.0 (vd 1af4:1002)
Searching bootorder for: /pci@i0cf8/*@3
Registering bootable: iPXE (PCI 00:03.0) (type:128 prio:9999 data:c9000372)
Searching bootorder for: /rom@genroms/vapic.bin
Registering bootable: Legacy option rom (type:129 prio:9999 data:ca000003)
Mapping hd drive 0x000fd800 to 0
drive 0x000fd800: PCHS=16383/16/63 translation=lba LCHS=1024/255/63 
s=104857600
Mapping cd drive 0x000fd7d0
Running option rom at ca00:0003
ebda moved from 9fc00 to 9f400
finalize PMM
malloc finalize
Returned 53248 bytes of ZoneHigh
e820 map has 7 items:
   0: 0000000000000000 - 000000000009f400 = 1 RAM
   1: 000000000009f400 - 00000000000a0000 = 2 RESERVED
   2: 00000000000f0000 - 0000000000100000 = 2 RESERVED
   3: 0000000000100000 - 00000000dfffd000 = 1 RAM
   4: 00000000dfffd000 - 00000000e0000000 = 2 RESERVED
   5: 00000000fffbc000 - 0000000100000000 = 2 RESERVED
   6: 0000000100000000 - 0000000420000000 = 1 RAM
locking shadow ram
Jump to int19
enter handle_19:


-------- PCI  INFO after boot ----------------------
   Bus  0, device   0, function 0:
     Host bridge: PCI device 8086:1237
       id ""
   Bus  0, device   1, function 0:
     ISA bridge: PCI device 8086:7000
       id ""
   Bus  0, device   1, function 1:
     IDE controller: PCI device 8086:7010
       BAR4: I/O at 0xc140 [0xc14f].
       id ""
   Bus  0, device   1, function 2:
     USB controller: PCI device 8086:7020
       IRQ 5.
       BAR4: I/O at 0xc100 [0xc11f].
       id ""
   Bus  0, device   1, function 3:
     Bridge: PCI device 8086:7113
       IRQ 9.
       id ""
   Bus  0, device   2, function 0:
     VGA controller: PCI device 1013:00b8
       BAR0: 32 bit prefetchable memory at 0xfc000000 [0xfdffffff].
       BAR1: 32 bit memory at 0xfebf0000 [0xfebf0fff].
       BAR6: 32 bit memory at 0xffffffffffffffff [0x0000fffe].
       id ""
   Bus  0, device   3, function 0:
     Ethernet controller: PCI device 10ec:8139
       IRQ 11.
       BAR0: I/O at 0xc000 [0xc0ff].
       BAR1: 32 bit memory at 0xfebf1000 [0xfebf10ff].
       BAR6: 32 bit memory at 0xffffffffffffffff [0x0000fffe].
       id "net0"
   Bus  0, device   5, function 0:
     Network controller: PCI device eace:eace
       IRQ 10.
       BAR0: 32 bit memory at 0xfebe0000 [0xfebeffff].
       BAR1: 64 bit prefetchable memory at 0xffffffffffffffff [0x1ffffffe].
       id ""
   Bus  0, device   6, function 0:
     RAM controller: PCI device 1af4:1002
       IRQ 10.
       BAR0: I/O at 0xc120 [0xc13f].
       id "balloon0"




--------------------- Seabios log PCI BAR 256MB: 
------------------------------------


Changing serial settings was 0/0 now 3/0
Start bios (version pre-0.6.3-20111201_162012-core-3000-3.et.endace.com)
enabling shadow ram
qemu_cfg_present=1
Find memory size
Ram Size=0xe0000000 (0x0000000320000000 high)
malloc setup
Relocating init from 0x000e01c0 to 0xdffe0980 (size 62800)
malloc fixup reloc
init ivt
init bda
init pic
init timer
CPU Mhz=2801
math cp init
init mtrr
pci setup
=== PCI bus & bridge init ===
PCI: pci_bios_init_bus_rec bus = 0x0
=== PCI device probing ===
PCI probe
PCI device 00:00.0 (vd=8086:1237 c=0600)
PCI device 00:01.0 (vd=8086:7000 c=0601)
PCI device 00:01.1 (vd=8086:7010 c=0101)
PCI device 00:01.2 (vd=8086:7020 c=0c03)
PCI device 00:01.3 (vd=8086:7113 c=0680)
PCI device 00:02.0 (vd=1013:00b8 c=0300)
PCI device 00:03.0 (vd=10ec:8139 c=0200)
PCI device 00:05.0 (vd=eace:eace c=0280)
PCI device 00:06.0 (vd=1af4:1002 c=0500)
Found 9 PCI devices (max PCI bus is 00)
=== PCI new allocation pass #1 ===
PCI: check devices bus 0
=== PCI new allocation pass #2 ===
PCI: init bases bus 0 (primary)
   type io max 100 sum 150 base c000
     size      100: 1 bar(s),     c000 ->     c0ff
     size       20: 2 bar(s),     c100 ->     c13f
     size       10: 1 bar(s),     c140 ->     c14f
   type mem max 10000 sum 32000 base febc0000
     size    10000: 3 bar(s), febc0000 -> febeffff
     size     1000: 2 bar(s), febf0000 -> febf1fff
   type prefmem max 2000000 sum 2000000 base fc000000
     size  2000000: 1 bar(s), fc000000 -> fdffffff
PCI: map device bus 0, bfd 0x0
PCI: map device bus 0, bfd 0x8
PCI: map device bus 0, bfd 0x9
   bar 4, addr c140, size 10 [io]
PCI: map device bus 0, bfd 0xa
   bar 4, addr c100, size 20 [io]
PCI: map device bus 0, bfd 0xb
PCI: map device bus 0, bfd 0x10
   bar 0, addr fc000000, size 2000000 [mem]
   bar 1, addr febf0000, size 1000 [mem]
   bar 6, addr febc0000, size 10000 [mem]
PCI: map device bus 0, bfd 0x18
   bar 0, addr c000, size 100 [io]
   bar 1, addr febf1000, size 100 [mem]
   bar 6, addr febd0000, size 10000 [mem]
PCI: map device bus 0, bfd 0x28
   bar 0, addr febe0000, size 10000 [mem]
   bar 1, addr 0, size 10000000 [mem]
PCI: map device bus 0, bfd 0x30
   bar 0, addr c120, size 20 [io]
PCI: bus=0 devfn=0x00: vendor_id=0x8086 device_id=0x1237
PCI: bus=0 devfn=0x08: vendor_id=0x8086 device_id=0x7000
PCI: bus=0 devfn=0x09: vendor_id=0x8086 device_id=0x7010
PCI: bus=0 devfn=0x0a: vendor_id=0x8086 device_id=0x7020
PCI: bus=0 devfn=0x0b: vendor_id=0x8086 device_id=0x7113
PCI: bus=0 devfn=0x10: vendor_id=0x1013 device_id=0x00b8
PCI: bus=0 devfn=0x18: vendor_id=0x10ec device_id=0x8139
PCI: bus=0 devfn=0x28: vendor_id=0xeace device_id=0xeace
PCI: bus=0 devfn=0x30: vendor_id=0x1af4 device_id=0x1002
init smm
boot order:
1: /pci@i0cf8/ide@1,1/drive@0/disk@0
2: /pci@i0cf8/ide@1,1/drive@1/disk@0
Found 2 cpu(s) max supported 2 cpu(s)
init bios32
init PMM
init PNPBIOS table
init keyboard
init mouse
init PIR table
init MPTable
MP table addr=0x000fda00 MPC table addr=0x000fda10 size=260
init SMBIOS tables
SMBIOS ptr=0x000fd9e0 table=0x000fd880 size=346
init ACPI tables
ACPI tables: RSDP=0x000fd850 RSDT=0xdfffd740
Scan for VGA option rom
Attempting to init PCI bdf 00:02.0 (vd 1013:00b8)
Copying option rom (size 35840) from 0xfebc0000 to c0000
Running option rom at c000:0003
Turning on vga text mode console
SeaBIOS (version pre-0.6.3-20111201_162012-core-3000-3.et.endace.com)

init usb
UHCI init on dev 00:01.2 (io=c100)
/dffdf000\ Start thread
/dffde000\ Start thread
/dffdd000\ Start thread
\dffdd000/ End thread
init ps2port
/dffdd000\ Start thread
init lpt
Found 0 lpt ports
init serial
Found 1 serial ports
init floppy drives
init hard drives
ATA controller 1 at 1f0/3f4/0 (irq 14 dev 9)
/dffdb000\ Start thread
ATA controller 2 at 170/374/0 (irq 15 dev 9)
/dffda000\ Start thread
init ahci
init virtio-blk
|dffdb000| ata0-0: QEMU HARDDISK ATA-7 Hard-Disk (51200 MiBytes)
|dffdb000| Searching bootorder for: /pci@i0cf8/*@1,1/drive@0/disk@0
|dffdb000| Registering bootable: ata0-0: QEMU HARDDISK ATA-7 Hard-Disk 
(51200 MiBytes) (type:2 prio:1 data:fd800)
\dffdb000/ End thread
|dffda000| DVD/CD [ata1-0: QEMU DVD-ROM ATAPI-4 DVD/CD]
|dffda000| Searching bootorder for: /pci@i0cf8/*@1,1/drive@1/disk@0
|dffda000| Registering bootable: DVD/CD [ata1-0: QEMU DVD-ROM ATAPI-4 
DVD/CD] (type:3 prio:2 data:fd7d0)
\dffda000/ End thread
|dffde000| set_address 0xdffe0150
|dffde000| config_usb: 0xdffdccec
|dffde000| device rev=0100 cls=00 sub=00 proto=00 size=08
|dffde000| usb_hid_init 0xdffdccec
\dffde000/ End thread
\dffdf000/ End thread
|dffdd000| PS2 keyboard initialized
\dffdd000/ End thread
All threads complete.
Scan for option roms
Attempting to init PCI bdf 00:00.0 (vd 8086:1237)
Attempting to init PCI bdf 00:01.0 (vd 8086:7000)
Attempting to init PCI bdf 00:01.2 (vd 8086:7020)
Attempting to init PCI bdf 00:01.3 (vd 8086:7113)
Attempting to init PCI bdf 00:03.0 (vd 10ec:8139)
Copying option rom (size 61440) from 0xfebd0000 to c9000
Running option rom at c900:0003
pmm call arg1=1
pmm01: handle=18ae1000
pmm call arg1=0
pmm00: length=f00 handle=18ae1000 flags=2
pmm call arg1=1
pmm01: handle=18ae2004
pmm call arg1=0
pmm00: length=4000 handle=18ae2004 flags=2
Attempting to init PCI bdf 00:05.0 (vd eace:eace)
Attempting to init PCI bdf 00:06.0 (vd 1af4:1002)
Searching bootorder for: /pci@i0cf8/*@3
Registering bootable: iPXE (PCI 00:03.0) (type:128 prio:9999 data:c9000372)
Searching bootorder for: /rom@genroms/vapic.bin
Registering bootable: Legacy option rom (type:129 prio:9999 data:ca000003)
Mapping hd drive 0x000fd800 to 0
drive 0x000fd800: PCHS=16383/16/63 translation=lba LCHS=1024/255/63 
s=104857600
Mapping cd drive 0x000fd7d0
Running option rom at ca00:0003
ebda moved from 9fc00 to 9f400
finalize PMM
malloc finalize
Returned 53248 bytes of ZoneHigh
e820 map has 7 items:
   0: 0000000000000000 - 000000000009f400 = 1 RAM
   1: 000000000009f400 - 00000000000a0000 = 2 RESERVED
   2: 00000000000f0000 - 0000000000100000 = 2 RESERVED
   3: 0000000000100000 - 00000000dfffd000 = 1 RAM
   4: 00000000dfffd000 - 00000000e0000000 = 2 RESERVED
   5: 00000000fffbc000 - 0000000100000000 = 2 RESERVED
   6: 0000000100000000 - 0000000420000000 = 1 RAM
locking shadow ram
Jump to int19
enter handle_19:
   NULL
Booting from Hard Disk...
Booting from 0000:7c00
unimplemented handle_1aXX:441:
    a=0000bb00  b=0000aa55  c=0000ffff  d=00000080 ds=0000 es=0000 ss=0000
   si=00007e00 di=00000800 bp=000007be sp=00007bfe cs=0000 ip=06e7  f=3246
unimplemented handle_1aXX:441:
    a=0000bb00  b=00000000  c=00000000  d=000009a0 ds=07c0 es=09a0 ss=0000
   si=00007be4 di=00000800 bp=000007be sp=00007c00 cs=07c0 ip=00db  f=3246
unimplemented handle_1aXX:441:
    a=0000bb00  b=00000000  c=0000005e  d=00000000 ds=07c0 es=2000 ss=0000
   si=00003808 di=00000000 bp=000007be sp=00007bda cs=07c0 ip=0f54  f=3246
unimplemented handle_1aXX:441:
    a=0000bb00  b=00000000  c=00000000  d=00000000 ds=0000 es=0000 ss=23de
   si=00000000 di=00000000 bp=00000000 sp=00001462 cs=2000 ip=0a39  f=3256
unimplemented handle_1aXX:441:
    a=0000bb00  b=00000000  c=00000000  d=00000000 ds=0000 es=0000 ss=23de
   si=00000000 di=00000000 bp=00000000 sp=00001462 cs=2000 ip=0a39  f=3256
invalid handle_legacy_disk:841:
    a=00001500  b=00000000  c=00000000  d=00000000 ds=0000 es=0000 ss=23de
   si=00000000 di=00000000 bp=00000000 sp=00001462 cs=2000 ip=0a1d  f=3246
invalid handle_legacy_disk:841:
    a=00001500  b=00000000  c=00000000  d=00000001 ds=0000 es=0000 ss=23de
   si=00000000 di=00000000 bp=00000000 sp=00001462 cs=2000 ip=0a1d  f=3246




--------------------- Seabios log PCI BAR 256MB: 
------------------------------------

   Bus  0, device   0, function 0:
     Host bridge: PCI device 8086:1237
       id ""
   Bus  0, device   1, function 0:
     ISA bridge: PCI device 8086:7000
       id ""
   Bus  0, device   1, function 1:
     IDE controller: PCI device 8086:7010
       BAR4: I/O at 0xc140 [0xc14f].
       id ""
   Bus  0, device   1, function 2:
     USB controller: PCI device 8086:7020
       IRQ 5.
       BAR4: I/O at 0xc100 [0xc11f].
       id ""
   Bus  0, device   1, function 3:
     Bridge: PCI device 8086:7113
       IRQ 9.
       id ""
   Bus  0, device   2, function 0:
     VGA controller: PCI device 1013:00b8
       BAR0: 32 bit prefetchable memory at 0xfc000000 [0xfdffffff].
       BAR1: 32 bit memory at 0xfebf0000 [0xfebf0fff].
       BAR6: 32 bit memory at 0xffffffffffffffff [0x0000fffe].
       id ""
   Bus  0, device   3, function 0:
     Ethernet controller: PCI device 10ec:8139
       IRQ 11.
       BAR0: I/O at 0xc000 [0xc0ff].
       BAR1: 32 bit memory at 0xfebf1000 [0xfebf10ff].
       BAR6: 32 bit memory at 0xffffffffffffffff [0x0000fffe].
       id "net0"
   Bus  0, device   5, function 0:
     Network controller: PCI device eace:eace
       IRQ 10.
       BAR0: 32 bit memory at 0xfebe0000 [0xfebeffff].
       BAR1: 64 bit prefetchable memory at 0xe0000000 [0xefffffff].
       id ""
   Bus  0, device   6, function 0:
     RAM controller: PCI device 1af4:1002
       IRQ 10.
       BAR0: I/O at 0xc120 [0xc13f].
       id "balloon0"

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Gerd Hoffmann]

  Hi,

> Ok Here are logs the faulty device is: 00:05.0.
> In the first case the BAR1 size is 512MB and it fails in Windows (Linux
> is fine, the kernel enumerates the bus and assigns the resource above 4GB),
> In the second case the BAR1 size is 256M and works fine.

> === PCI new allocation pass #1 ===
> PCI: check devices bus 0

Hmm, with 512 MB seabios should have paniced here with:

PCI: out of address space

> PCI: map device bus 0, bfd 0x28
>   bar 0, addr febe0000, size 10000 [mem]
>   bar 1, addr 0, size 20000000 [mem]

Somehow seabios didn't recognise the bar correctly it seems (both 512
and 256 MB cases look the same).  For the 256 MB case seabios should
have mapped the bar @ 0xe0000000.

cheers,
  Gerd

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Gerd Hoffmann]

  Hi,

>> PCI: map device bus 0, bfd 0x28
>>   bar 0, addr febe0000, size 10000 [mem]
>>   bar 1, addr 0, size 20000000 [mem]
> 
> Somehow seabios didn't recognise the bar correctly it seems (both 512
> and 256 MB cases look the same).  For the 256 MB case seabios should
> have mapped the bar @ 0xe0000000.

... and it should also have figured it is prefetchable memory.  Was pci
config space messed up somehow?  What does 'lspci -v' say once you've
booted the machine with linux?

What qemu version you are running?
What kind of device is this?
Emulated?  Code somewhere?
Or a real device passed through to the guest?

cheers,
  Gerd

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Alexey Korolev]

Hi Gerd,

We have very early prototype of data acquisition device, with quite 
large MMIO buffer. It is an emulated device.
We are running the 0.15 release.
0.15 doesn't work correctly with 64bit BARs so I've already added some 
hacks to Seabios to let OS to choose the memory region.
Thus you see bar 1, addr 0 in seabios log.
Sorry that I haven't specified all this initially. I just want to make 
64bit PCI bar working properly. Linux guests works correctly (except 
early versions - not investigated this yet). At the moment I have some 
issues with windows which relies on ACPI _CRS.

Thanks,
Alexey


>    Hi,
>
>>> PCI: map device bus 0, bfd 0x28
>>>    bar 0, addr febe0000, size 10000 [mem]
>>>    bar 1, addr 0, size 20000000 [mem]
>> Somehow seabios didn't recognise the bar correctly it seems (both 512
>> and 256 MB cases look the same).  For the 256 MB case seabios should
>> have mapped the bar @ 0xe0000000.
> ... and it should also have figured it is prefetchable memory.  Was pci
> config space messed up somehow?  What does 'lspci -v' say once you've
> booted the machine with linux?
>
> What qemu version you are running?
> What kind of device is this?
> Emulated?  Code somewhere?
> Or a real device passed through to the guest?
>
> cheers,
>    Gerd

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Gerd Hoffmann]

On 12/05/11 05:29, Alexey Korolev wrote:
> Hi Gerd,
> 
> We have very early prototype of data acquisition device, with quite
> large MMIO buffer. It is an emulated device.
> We are running the 0.15 release.
> 0.15 doesn't work correctly with 64bit BARs so I've already added some
> hacks to Seabios to let OS to choose the memory region.
> Thus you see bar 1, addr 0 in seabios log.

I'd strongly suggest to move forward to qemu 1.0.  Memory region
handling has seen a major rewrite in 1.0 (memory api patches by avi).
Chances are good that the 64bit bar bugs in qemu have been fixed meanwhile.

I have experimental patches which add a 64bit bar to the qxl device and
seabios handles it just fine (although memory-backed not mmio), except
that there is no support yet to map 64bit bars above 4G.

It shouldn't be that hard to add the latter though.  seabios needs two
more pci_region_type (PCI_REGION_TYPE_MEM_64 and
PCI_REGION_TYPE_PREFMEM_64) to track and map 64bit bars separately.  And
a address space window where it can map 64bit bars to.

> Sorry that I haven't specified all this initially. I just want to make
> 64bit PCI bar working properly. Linux guests works correctly (except
> early versions - not investigated this yet). At the moment I have some
> issues with windows which relies on ACPI _CRS.

... and a _CRS entry for the 64bit bar address space window of course.

cheers,
  Gerd

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Alexey Korolev]

Hi Gerd,


> I'd strongly suggest to move forward to qemu 1.0.  Memory region
> handling has seen a major rewrite in 1.0 (memory api patches by avi).
> Chances are good that the 64bit bar bugs in qemu have been fixed meanwhile.
Thanks, will try it. Hope it will be better.
> I have experimental patches which add a 64bit bar to the qxl device and
> seabios handles it just fine (although memory-backed not mmio), except
> that there is no support yet to map 64bit bars above 4G.
>
> It shouldn't be that hard to add the latter though.  seabios needs two
> more pci_region_type (PCI_REGION_TYPE_MEM_64 and
> PCI_REGION_TYPE_PREFMEM_64) to track and map 64bit bars separately.  And
> a address space window where it can map 64bit bars to.
Right. This is a thing I'm thinking about now. I seems that the 
specifying 0x0 address in 64bit BARS is a bad idea. At least older 
versions of Linux just hang as soon as requested range does not fit in 
first 4GB.
So the only option would be specifying the particular address range. It 
seems this works for everything - yet.
>> Sorry that I haven't specified all this initially. I just want to make
>> 64bit PCI bar working properly. Linux guests works correctly (except
>> early versions - not investigated this yet). At the moment I have some
>> issues with windows which relies on ACPI _CRS.
> ... and a _CRS entry for the 64bit bar address space window of course.
Yes.

Cheers,
Alexey

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Alexey Korolev]

Hi,
>>
>> It shouldn't be that hard to add the latter though.  seabios needs two
>> more pci_region_type (PCI_REGION_TYPE_MEM_64 and
>> PCI_REGION_TYPE_PREFMEM_64) to track and map 64bit bars separately.  And
>> a address space window where it can map 64bit bars to.
> Right. This is a thing I'm thinking about now. I seems that the 
> specifying 0x0 address in 64bit BARS is a bad idea. At least older 
> versions of Linux just hang as soon as requested range does not fit in 
> first 4GB.
> So the only option would be specifying the particular address range. 
> It seems this works for everything - yet.
I wonder if there any particular reason to separate prefetchable a 
non-prefetchable memory regions in pciinit? Extra two more regions would 
make code more complex.

Regards,
Alexey

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Kevin O'Connor]

On Wed, Dec 14, 2011 at 05:30:23PM +1300, Alexey Korolev wrote:
> Hi,
> >>
> >>It shouldn't be that hard to add the latter though.  seabios needs two
> >>more pci_region_type (PCI_REGION_TYPE_MEM_64 and
> >>PCI_REGION_TYPE_PREFMEM_64) to track and map 64bit bars separately.  And
> >>a address space window where it can map 64bit bars to.
> >Right. This is a thing I'm thinking about now. I seems that the
> >specifying 0x0 address in 64bit BARS is a bad idea. At least older
> >versions of Linux just hang as soon as requested range does not
> >fit in first 4GB.
> >So the only option would be specifying the particular address
> >range. It seems this works for everything - yet.
> I wonder if there any particular reason to separate prefetchable a
> non-prefetchable memory regions in pciinit? Extra two more regions
> would make code more complex.

If I understand this correctly, the prefmem and normal mem separation
is for pci bridges.  Devices behind a bridge need to have all their
prefmem regions consecutive and not overlapping with all the normal
mem ranges.  That way the bridge device can advertise just one prefmem
region and one normal mem region which encapsulates all the devices
behind it.

-Kevin

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Gerd Hoffmann]

On 12/14/11 05:30, Alexey Korolev wrote:
> Hi,
>>>
>>> It shouldn't be that hard to add the latter though.  seabios needs two
>>> more pci_region_type (PCI_REGION_TYPE_MEM_64 and
>>> PCI_REGION_TYPE_PREFMEM_64) to track and map 64bit bars separately.  And
>>> a address space window where it can map 64bit bars to.
>> Right. This is a thing I'm thinking about now. I seems that the
>> specifying 0x0 address in 64bit BARS is a bad idea. At least older
>> versions of Linux just hang as soon as requested range does not fit in
>> first 4GB.
>> So the only option would be specifying the particular address range.
>> It seems this works for everything - yet.
> I wonder if there any particular reason to separate prefetchable a
> non-prefetchable memory regions in pciinit? Extra two more regions would
> make code more complex.

Oh yes, there is.  Which reminds me that the whole thing isn't that easy
unfortunaly ...

The reason are pci bridges.  They have two memory regions, one for
prefetchable and one for non-prefetchable memory.  All devices behind a
pci bridge must have the bars within the bridges memory regions, thats
why they are grouped together.

This also implies that a 32bit and a 64bit bar (of the same type) behind
a pci bridge must be mapped next to each other, so moving up 64bit bars
unconditionally isn't going to fly.  Devices behind bridges need some
extra care, only when all bars are 64bit capable they can actually be
mapped above 4G.

cheers,
  Gerd

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Alexey Korolev]

>> I wonder if there any particular reason to separate prefetchable a
>> non-prefetchable memory regions in pciinit? Extra two more regions would
>> make code more complex.
> Oh yes, there is.  Which reminds me that the whole thing isn't that easy
> unfortunaly ...
>
> The reason are pci bridges.  They have two memory regions, one for
> prefetchable and one for non-prefetchable memory.  All devices behind a
> pci bridge must have the bars within the bridges memory regions, thats
> why they are grouped together.
>
> This also implies that a 32bit and a 64bit bar (of the same type) behind
> a pci bridge must be mapped next to each other, so moving up 64bit bars
> unconditionally isn't going to fly.  Devices behind bridges need some
> extra care, only when all bars are 64bit capable they can actually be
> mapped above 4G.
The qemu actually does not simulate PCI bridges at all. So good question 
shall we bother about this?  I did some preliminary tests: 64bit BARs 
are working quite well for linux 2.6.18 - 3.0 and windows 2008.

Also I've found important detail that according to PCI architecture 
specification, the bridges can describe 64bit ranges for prefetchable 
type of memory only. So it's very unlikely that devices exporting 64bit 
non-prefetchable BARs. I guess we just need to add one extra type.

Even if there are two separate prefetchable memory regions (32 bit and 
64bit), it won't be a problem as there is no bridge on the 440FX inside 
the virtual machine.

Cheers,
Alexey

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Gerd Hoffmann]

On 12/16/11 05:41, Alexey Korolev wrote:
>>> I wonder if there any particular reason to separate prefetchable a
>>> non-prefetchable memory regions in pciinit? Extra two more regions would
>>> make code more complex.
>> Oh yes, there is.  Which reminds me that the whole thing isn't that easy
>> unfortunaly ...
>>
>> The reason are pci bridges.  They have two memory regions, one for
>> prefetchable and one for non-prefetchable memory.  All devices behind a
>> pci bridge must have the bars within the bridges memory regions, thats
>> why they are grouped together.
>>
>> This also implies that a 32bit and a 64bit bar (of the same type) behind
>> a pci bridge must be mapped next to each other, so moving up 64bit bars
>> unconditionally isn't going to fly.  Devices behind bridges need some
>> extra care, only when all bars are 64bit capable they can actually be
>> mapped above 4G.
> The qemu actually does not simulate PCI bridges at all. So good question
> shall we bother about this?

Yes.  There is work in progress to add pci-express and a more modern
chipset emulation to qemu.

I think for now it is fine if we simply map everything behind a bridge
below 4G and hash out the details (i.e. whenever we can move the bridge
memory window above 4G or not) later.

> I did some preliminary tests: 64bit BARs
> are working quite well for linux 2.6.18 - 3.0 and windows 2008.

Nice.

> Also I've found important detail that according to PCI architecture
> specification, the bridges can describe 64bit ranges for prefetchable
> type of memory only. So it's very unlikely that devices exporting 64bit
> non-prefetchable BARs. I guess we just need to add one extra type.

Agree.

> Even if there are two separate prefetchable memory regions (32 bit and
> 64bit), it won't be a problem as there is no bridge on the 440FX inside
> the virtual machine.

Yes, devices attached to the root bus don't have to care about bridge
windows.

cheers,
  Gerd

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Alexey Korolev]

Isaku san,

I've just added you to discussion.
There are some issues with PCI 64bit support in Windows. Windows fails 
to assign the resource if it doesn't fit in first 4GB window.

I really don't know why it happens.
One of the possibilities is related to lack of _DSM method in ACPI.

Another guesse could be related to the fact that 440FX only supports 
32bit PCI bus interface and windows may limit PCI address range to first 
4GB for PCI devices under this bridge.
I remember you were working on Q35 chipset simulation, I wonder if it is 
working and would it be possible to try?

Thanks,
Alexey
> On Wed, Nov 30, 2011 at 02:04:08PM +1300, Alexey Korolev wrote:
>> Hi,
>>
>> We have got some issues with 64bit PCI devices support under Windows guests.
>> Windows fails to start any PCI devices with 64bit BARs when size
>> exceeds 512MB with error code 12 (can't allocate resources). In
>> other words it fails when the PCI memory region is located above
>> 4GB.
>>
>> I tried to investigate this problem and found document from Microsoft:
>> http://msdn.microsoft.com/en-us/windows/hardware/gg462986
>>
>> It states that the _DSM method must be implemented to support
>> devices above 4GB.
> That's not how I read it:
> 	Windows Vista always respects the boot configuration of devices above
> 	4 GB, considering the processor’s addressing capability and the version
> 	of the Windows operating system that is running.
>
>> Unfortunately I'm not familiar with ACPI code of seabios, so can't
>> implement the _DSM method. May be you have other ideas what needs to
>> be done to fix it? Any help is appreciated.
>>
>> Thanks,
>> Alexey
> Could you share some more detail about your setup?
>

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Michael S. Tsirkin]

On Thu, Dec 01, 2011 at 06:49:54PM +1300, Alexey Korolev wrote:
> Isaku san,
> 
> I've just added you to discussion.
> There are some issues with PCI 64bit support in Windows. Windows
> fails to assign the resource if it doesn't fit in first 4GB window.
> 
> I really don't know why it happens.
> One of the possibilities is related to lack of _DSM method in ACPI.
> 
> Another guesse could be related to the fact that 440FX only supports
> 32bit PCI bus interface and windows may limit PCI address range to
> first 4GB for PCI devices under this bridge.
> I remember you were working on Q35 chipset simulation, I wonder if
> it is working and would it be possible to try?
> 
> Thanks,
> Alexey

Maybe the range above 4G needs to be declared in the _CRS
resource?

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Alexey Korolev]

Hi Michael,

Thank you for good advice, you are right.  When I added new range above 
4GB in _CRS the problem has gone.
   QWordMemory (ResourceProducer, PosDecode, MinFixed, MaxFixed, 
NonCacheable, ReadWrite,
                    0x00000000,          // Address Space Granularity
                    0x100000000,        // Address Range Minimum
                    0x3FFFFFFFF,        // Address Range Maximum
                    0x00000000,          // Address Translation Offset
                    0x400000000,        // Address Length
                    ,, , AddressRangeMemory, TypeStatic)

The only big problem with this range - as soon as I have more than 3GB 
of RAM, windows will boot in BSOD. The problem relates to memory range 
intersection.
Unfortunately it is not possible to predict how many GB of RAM the 
virtual machine could have - so it's difficult to specify a particular 
region.
Do you have any ideas what can be done to solve this problem?

Regards,
Alexey

> On Thu, Dec 01, 2011 at 06:49:54PM +1300, Alexey Korolev wrote:
>> Isaku san,
>>
>> I've just added you to discussion.
>> There are some issues with PCI 64bit support in Windows. Windows
>> fails to assign the resource if it doesn't fit in first 4GB window.
>>
>> I really don't know why it happens.
>> One of the possibilities is related to lack of _DSM method in ACPI.
>>
>> Another guesse could be related to the fact that 440FX only supports
>> 32bit PCI bus interface and windows may limit PCI address range to
>> first 4GB for PCI devices under this bridge.
>> I remember you were working on Q35 chipset simulation, I wonder if
>> it is working and would it be possible to try?
>>
>> Thanks,
>> Alexey
> Maybe the range above 4G needs to be declared in the _CRS
> resource?

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Michael S. Tsirkin]

On Mon, Dec 05, 2011 at 05:20:32PM +1300, Alexey Korolev wrote:
> Hi Michael,
> 
> Thank you for good advice, you are right.  When I added new range
> above 4GB in _CRS the problem has gone.
>   QWordMemory (ResourceProducer, PosDecode, MinFixed, MaxFixed,
> NonCacheable, ReadWrite,
>                    0x00000000,          // Address Space Granularity
>                    0x100000000,        // Address Range Minimum
>                    0x3FFFFFFFF,        // Address Range Maximum
>                    0x00000000,          // Address Translation Offset
>                    0x400000000,        // Address Length
>                    ,, , AddressRangeMemory, TypeStatic)
> 
> The only big problem with this range - as soon as I have more than
> 3GB of RAM, windows will boot in BSOD. The problem relates to memory
> range intersection.
> Unfortunately it is not possible to predict how many GB of RAM the
> virtual machine could have - so it's difficult to specify a
> particular region.
> Do you have any ideas what can be done to solve this problem?
> 
> Regards,
> Alexey

Two possible ideas:
1. Pass the value in from qemu
2. Get a range toward the upper end of the memory, around 1<<40

> >On Thu, Dec 01, 2011 at 06:49:54PM +1300, Alexey Korolev wrote:
> >>Isaku san,
> >>
> >>I've just added you to discussion.
> >>There are some issues with PCI 64bit support in Windows. Windows
> >>fails to assign the resource if it doesn't fit in first 4GB window.
> >>
> >>I really don't know why it happens.
> >>One of the possibilities is related to lack of _DSM method in ACPI.
> >>
> >>Another guesse could be related to the fact that 440FX only supports
> >>32bit PCI bus interface and windows may limit PCI address range to
> >>first 4GB for PCI devices under this bridge.
> >>I remember you were working on Q35 chipset simulation, I wonder if
> >>it is working and would it be possible to try?
> >>
> >>Thanks,
> >>Alexey
> >Maybe the range above 4G needs to be declared in the _CRS
> >resource?

Re: [Qemu-devel] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Alexey Korolev]

On 05/12/11 19:31, Michael S. Tsirkin wrote:
> On Mon, Dec 05, 2011 at 05:20:32PM +1300, Alexey Korolev wrote:
>> Hi Michael,
>>
>> Thank you for good advice, you are right.  When I added new range
>> above 4GB in _CRS the problem has gone.
>>    QWordMemory (ResourceProducer, PosDecode, MinFixed, MaxFixed,
>> NonCacheable, ReadWrite,
>>                     0x00000000,          // Address Space Granularity
>>                     0x100000000,        // Address Range Minimum
>>                     0x3FFFFFFFF,        // Address Range Maximum
>>                     0x00000000,          // Address Translation Offset
>>                     0x400000000,        // Address Length
>>                     ,, , AddressRangeMemory, TypeStatic)
>>
>> The only big problem with this range - as soon as I have more than
>> 3GB of RAM, windows will boot in BSOD. The problem relates to memory
>> range intersection.
>> Unfortunately it is not possible to predict how many GB of RAM the
>> virtual machine could have - so it's difficult to specify a
>> particular region.
>> Do you have any ideas what can be done to solve this problem?
>>
>> Regards,
>> Alexey
> Two possible ideas:
> 1. Pass the value in from qemu
Do you mean to create the 64bit region dynamically? I've tried to obtain 
RAM size somehow inside DSL code, but the ACPI spec doesn't tell how to 
do that.

> 2. Get a range toward the upper end of the memory, around 1<<40
>
Yes. This solution works great. And this is very simple as well. Just 
wondering if it will be good as a complete solution?

Re: [Qemu-devel] [SeaBIOS] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Gerd Hoffmann]

  Hi,

>> Two possible ideas:
>> 1. Pass the value in from qemu
> Do you mean to create the 64bit region dynamically? I've tried to obtain
> RAM size somehow inside DSL code, but the ACPI spec doesn't tell how to
> do that.

There is a global variable IIRC.  You could also check the e820 table
passed in from qemu.

>> 2. Get a range toward the upper end of the memory, around 1<<40
>>
> Yes. This solution works great. And this is very simple as well. Just
> wondering if it will be good as a complete solution?

I would have tried this first too ;)

Care to share the patches so we can review & merge them?

thanks,
  Gerd

Re: [Qemu-devel] [SeaBIOS] [BUG] [Seabios] PCI 64bit BARs on Win2008 - unable to start the device. (ACPI lacks the _DSM method)

[Alexey Korolev]

>>> 2. Get a range toward the upper end of the memory, around 1<<40
>>>
>> Yes. This solution works great. And this is very simple as well. Just
>> wondering if it will be good as a complete solution?
> I would have tried this first too ;)
>
> Care to share the patches so we can review&  merge them?
No worries. Just need to complete and test the code and I'll post RFC 
patches shortly.