[Qemu-devel] Unusual physical address when using 64-bit BAR

[Cam Macdonell <cam@cs.ualberta.ca>]

Hi,

I'm trying to use a 64-bit BAR for my shared memory device.  In simply
changing the memory type in pci_register_bar() to
PCI_BASE_ADDRESS_MEM_TYPE_64 I get an unusual physical address for
that BAR (and my driver crashes in pci_ioremap).

from lspci:

00:04.0 RAM memory: Qumranet, Inc. Device 1110
        Subsystem: Qumranet, Inc. Device 1100
        Flags: fast devsel, IRQ 10
        Memory at f1020000 (32-bit, non-prefetchable) [size=1K]
        Memory at f1021000 (32-bit, non-prefetchable) [size=4K]
        Memory at c20000000000 (64-bit, non-prefetchable) [size=1024M]
        Capabilities: <access denied>
00: f4 1a 10 11 03 00 10 00 00 00 00 05 00 00 00 00
10: 00 00 02 f1 00 10 02 f1 04 00 00 00 00 c2 00 00
20: 00 00 00 00 00 00 00 00 00 00 00 00 f4 1a 00 11
30: 00 00 00 00 40 00 00 00 00 00 00 00 0b 01 00 00

with DEBUG_MEMREG, I see

kvm_unregister_memory_area:666 Unregistering memory region
c20000000000 (40000000)
kvm_destroy_phys_mem:649 slot 7 start c20000000000 len 0 flags 0
IVSHMEM: addr = 3221225472 size = 1073741824
kvm_register_phys_mem:605 memory: gpa: c200c0000000, size: 40000000,
uaddr: 7f6dd7ffe000, slot: 7, flags: 0
kvm_unregister_memory_area:666 Unregistering memory region
c200c0000000 (40000000)
kvm_destroy_phys_mem:649 slot 7 start c200c0000000 len 0 flags 0
IVSHMEM: addr = 0 size = 1073741824
kvm_register_phys_mem:605 memory: gpa: c20000000000, size: 40000000,
uaddr: 7f6dd7ffe000, slot: 7, flags: 0
kvm_unregister_memory_area:666 Unregistering memory region
c20000000000 (40000000)
kvm_destroy_phys_mem:649 slot 7 start c20000000000 len 0 flags 0
IVSHMEM: addr = 0 size = 1073741824
kvm_register_phys_mem:605 memory: gpa: ffffffff00000000, size:
40000000, uaddr: 7f6dd7ffe000, slot: 7, flags: 0
kvm_unregister_memory_area:666 Unregistering memory region
ffffffff00000000 (40000000)
kvm_destroy_phys_mem:649 slot 7 start ffffffff00000000 len 0 flags 0
IVSHMEM: addr = 0 size = 1073741824
kvm_register_phys_mem:605 memory: gpa: c20000000000, size: 40000000,
uaddr: 7f6dd7ffe000, slot: 7, flags: 0

(the IVSHMEM lines are my debug statements)

address sizes   : 40 bits physical, 48 bits virtual  (guest)
address sizes   : 38 bits physical, 48 bits virtual  (host)

Thanks,
Cam