Re: [Qemu-devel] [PATCH 0/2] acpi: Fix PCI hole handling on SRAT table

[Igor Mammedov]

On Thu,  9 Jan 2014 17:12:41 -0200
Eduardo Habkost <address@hidden> wrote:

> The original SeaBIOS code used the RamSize variable, that was used by
> SeaBIOS for the size of RAM below 4GB, not for all RAM. When copied to
> QEMU, the code was changed to use the full RAM size, and this broke the
> build_srat() code that handles the PCI hole.
> 
> This series fixes the problem by restoring the original behavior from SeaBIOS.
> 
> Example Linux guest dmesg output when the bug is present (using -m 4G and 4 
> 1GB
> NUMA nodes):
> 
>   e820: BIOS-provided physical RAM map:
>   BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
>   BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
>   BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
>   BIOS-e820: [mem 0x0000000000100000-0x00000000dfffdfff] usable
>   BIOS-e820: [mem 0x00000000dfffe000-0x00000000dfffffff] reserved
>   BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] reserved
>   BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
>   BIOS-e820: [mem 0x0000000100000000-0x000000011fffffff] usable
>   e820: update [mem 0x00000000-0x00000fff] usable ==> reserved
>   e820: remove [mem 0x000a0000-0x000fffff] usable
>   e820: last_pfn = 0x120000 max_arch_pfn = 0x400000000
>   e820: last_pfn = 0xdfffe max_arch_pfn = 0x400000000
>   ACPI: SRAT 00000000dffffc0e 00160 (v01 BOCHS  BXPCSRAT 00000001 BXPC 
> 00000001)
>   SRAT: PXM 0 -> APIC 0x00 -> Node 0
>   SRAT: PXM 1 -> APIC 0x01 -> Node 1
>   SRAT: PXM 2 -> APIC 0x02 -> Node 2
>   SRAT: PXM 3 -> APIC 0x03 -> Node 3
>   SRAT: Node 0 PXM 0 [mem 0x00000000-0x0009ffff]
>   SRAT: Node 0 PXM 0 [mem 0x00100000-0x3fffffff]
>   SRAT: Node 1 PXM 1 [mem 0x40000000-0x7fffffff]
>   SRAT: Node 2 PXM 2 [mem 0x80000000-0xbfffffff]
>   SRAT: Node 3 PXM 3 [mem 0xc0000000-0xffffffff]
>   NUMA: nodes only cover 3583MB of your 4095MB e820 RAM. Not used.
>   e820: [mem 0xe0000000-0xfeffbfff] available for PCI devices
>   e820: reserve RAM buffer [mem 0x0009fc00-0x0009ffff]
>   e820: reserve RAM buffer [mem 0xdfffe000-0xdfffffff]
> 
> Output after the series is applied:
> 
>   e820: BIOS-provided physical RAM map:
>   BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
>   BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
>   BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
>   BIOS-e820: [mem 0x0000000000100000-0x00000000dfffdfff] usable
>   BIOS-e820: [mem 0x00000000dfffe000-0x00000000dfffffff] reserved
>   BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] reserved
>   BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
>   BIOS-e820: [mem 0x0000000100000000-0x000000011fffffff] usable
>   e820: update [mem 0x00000000-0x00000fff] usable ==> reserved
>   e820: remove [mem 0x000a0000-0x000fffff] usable
>   e820: last_pfn = 0x120000 max_arch_pfn = 0x400000000
>   e820: last_pfn = 0xdfffe max_arch_pfn = 0x400000000
>   ACPI: SRAT 00000000dffffc0e 00160 (v01 BOCHS  BXPCSRAT 00000001 BXPC 
> 00000001)
>   SRAT: PXM 0 -> APIC 0x00 -> Node 0
>   SRAT: PXM 1 -> APIC 0x01 -> Node 1
>   SRAT: PXM 2 -> APIC 0x02 -> Node 2
>   SRAT: PXM 3 -> APIC 0x03 -> Node 3
>   SRAT: Node 0 PXM 0 [mem 0x00000000-0x0009ffff]
>   SRAT: Node 0 PXM 0 [mem 0x00100000-0x3fffffff]
>   SRAT: Node 1 PXM 1 [mem 0x40000000-0x7fffffff]
>   SRAT: Node 2 PXM 2 [mem 0x80000000-0xbfffffff]
>   SRAT: Node 3 PXM 3 [mem 0xc0000000-0xdfffffff]
>   SRAT: Node 3 PXM 3 [mem 0x100000000-0x11fffffff]
>   e820: [mem 0xe0000000-0xfeffbfff] available for PCI devices
>   e820: reserve RAM buffer [mem 0x0009fc00-0x0009ffff]
>   e820: reserve RAM buffer [mem 0xdfffe000-0xdfffffff]
> 
> 
> Eduardo Habkost (2):
>   pc: Save size of RAM below 4GB
>   acpi-build: Fix PCI hole handling on build_srat()
> 
>  hw/i386/acpi-build.c | 10 +++++-----
>  hw/i386/pc.c         |  1 +
>  include/hw/i386/pc.h |  2 +-
>  3 files changed, 7 insertions(+), 6 deletions(-)
> 

since purpose of the the block you are touching is to exclude PCI hole
from SRAT could you use acpi_get_pci_info() instead?