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Re: [Qemu-devel] [PATCH] pc: limit 64 bit hole to 2G by default
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] pc: limit 64 bit hole to 2G by default |
Date: |
Wed, 24 Jul 2013 15:18:01 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 |
Il 24/07/2013 15:14, Michael S. Tsirkin ha scritto:
> On Wed, Jul 24, 2013 at 02:59:18PM +0200, Paolo Bonzini wrote:
>> Il 24/07/2013 11:51, Michael S. Tsirkin ha scritto:
>>>> Current seabios uses a slightly different approach: the 64bit hole is
>>>> present only in case it is actually used to map bars there, and seabios
>>>> tries to fit everything into the 32bit hole first.
>>>
>>> Yes. But this doesn't work with device hotplug.
>>
>> Are you preserving that behavior for older machine types?
>
> Older machine types (1.5 and back) don't report PCI hole size to guests
> so there's nothing to preserve.
So pc-1.5 and older always use the SeaBIOS ACPI tables, even on new
QEMU? (I guess I should review your ACPI table patches).
Paolo
> This means there's not much I can do for pc-1.5: as before this
> patch, hotplug of devices with large BARs won't work,
> and some windows guests will crash if a device with a huge
> BAR is added statically.
>
>> (Also, what happens if you do -global i440FX-pcihost.pci_hole64_size=0?
>> Does that return a _CRS with only the 32-bit hole)?
>>
>> Paolo
>
> Yes.
>
Re: [Qemu-devel] [PATCH] pc: limit 64 bit hole to 2G by default, Igor Mammedov, 2013/07/25