Uhmm. I assume this should be done in PciBus driver.
It will be a burden to let each PciHotPlugInitDxe to fix the smallest IO window.
+ PciBus maintainer: Ray Ni <ray...@intel.com> and Hao A Wu <hao.a...@intel.com>
What's your opinion?
> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Gerd
> Hoffmann
> Sent: Monday, November 28, 2022 2:26 PM
> To: devel@edk2.groups.io
> Cc: Oliver Steffen <ostef...@redhat.com>; Gerd Hoffmann
> <kra...@redhat.com>; Pawel Polawski <ppola...@redhat.com>; Ard
> Biesheuvel <ardb+tianoc...@kernel.org>; Justen, Jordan L
> <jordan.l.jus...@intel.com>; Yao, Jiewen <jiewen....@intel.com>
> Subject: [edk2-devel] [PATCH 1/1] OvmfPkg/PciHotPlugInitDxe: fix io
> window size
>
> Smallest IO window size for PCI bridges is 0x1000. Add a check and
> fixup the Exponent of needed. Avoids broken resource assignments
> like this:
>
> [ ... ]
> PciBus: Resource Map for Root Bridge PciRoot(0x0)
> Type = Io16; Base = 0x6000; Length = 0x7000; Alignment = 0xFFF
> [ ... ]
> Base = 0xC000; Length = 0x200; Alignment = 0xFFF; Owner =
> PPB
> [00|02|00:**]
> Base = 0xC200; Length = 0x40; Alignment = 0x3F; Owner =
> PCI
> [00|1F|03:20]
> Base = 0xC240; Length = 0x20; Alignment = 0x1F; Owner =
> PCI
> [00|1F|02:20]
> [ ... ]
>
> ... which the linux kernel fixes up later:
>
> [ 0.644657] pci 0000:00:1f.3: BAR 4: assigned [io 0x1000-0x103f]
> [ 0.646833] pci 0000:00:1f.2: BAR 4: assigned [io 0x1040-0x105f]
>
> With the patch applied:
>
> { ... ]
> PciBus: Resource Map for Root Bridge PciRoot(0x0)
> Type = Io16; Base = 0x6000; Length = 0x8000; Alignment = 0xFFF
> [ ... ]
> Base = 0xC000; Length = 0x1000; Alignment = 0xFFF;
> Owner
> = PPB [00|02|00:**]
> Base = 0xD000; Length = 0x40; Alignment = 0x3F; Owner =
> PCI
> [00|1F|03:20]
> Base = 0xD040; Length = 0x20; Alignment = 0x1F; Owner =
> PCI
> [00|1F|02:20]
> [ ... ]
>
> Signed-off-by: Gerd Hoffmann <kra...@redhat.com>
> ---
> OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.c
> b/OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.c
> index 3f9c84cf2b54..6c8bbc3b199d 100644
> --- a/OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.c
> +++ b/OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.c
> @@ -117,6 +117,10 @@ SetIoPadding (
> IN UINTN SizeExponent
> )
> {
> + if (SizeExponent < 12) {
> + SizeExponent = 12;
> + }
> +
> Descriptor->ResType = ACPI_ADDRESS_SPACE_TYPE_IO;
> Descriptor->AddrLen = LShiftU64 (1, SizeExponent);
> Descriptor->AddrRangeMax = Descriptor->AddrLen - 1;
> --
> 2.38.1
>
>
>
>
>
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