* [Qemu-devel] Why Qemu doesn't present L3 cache info for guest?
@ 2016-08-25 7:09 Shannon Zhao
2016-08-25 12:46 ` Eduardo Habkost
0 siblings, 1 reply; 2+ messages in thread
From: Shannon Zhao @ 2016-08-25 7:09 UTC (permalink / raw)
To: qemu-devel, Paolo Bonzini, Eduardo Habkost
Cc: longpeng, Huangpeng (Peter), Gonglei (Arei)
Hi guys,
Looking at the codes, for pc-2.4 machine it enables host-cache-info for
guest so guest can get the L3 cache info of host. But since QEMU has its
own rule to generate ACPI ID, guest will not use the L3 cache correctly.
I also notice that QEMU present L1 and L2 cache for guest via its own
rule, why it not present L3 cache info which is consistent with the ACPI
ID? Are there any downsides?
Thanks,
--
Shannon
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [Qemu-devel] Why Qemu doesn't present L3 cache info for guest?
2016-08-25 7:09 [Qemu-devel] Why Qemu doesn't present L3 cache info for guest? Shannon Zhao
@ 2016-08-25 12:46 ` Eduardo Habkost
0 siblings, 0 replies; 2+ messages in thread
From: Eduardo Habkost @ 2016-08-25 12:46 UTC (permalink / raw)
To: Shannon Zhao
Cc: qemu-devel, Paolo Bonzini, longpeng, Huangpeng (Peter),
Gonglei (Arei)
On Thu, Aug 25, 2016 at 03:09:27PM +0800, Shannon Zhao wrote:
> Hi guys,
>
> Looking at the codes, for pc-2.4 machine it enables host-cache-info for
> guest so guest can get the L3 cache info of host. But since QEMU has its
> own rule to generate ACPI ID, guest will not use the L3 cache correctly.
>
> I also notice that QEMU present L1 and L2 cache for guest via its own
> rule, why it not present L3 cache info which is consistent with the ACPI
> ID? Are there any downsides?
host-cache-info is there only for compatibility with old behavior
of "-cpu host", but I wouldn't advise anyone to use it. We would
need a proper way to configure cache information exposed to the
guest (including both CPUID and anything that would be exposed
through ACPI), but we don't have one yet.
--
Eduardo
^ permalink raw reply [flat|nested] 2+ messages in thread
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2016-08-25 7:09 [Qemu-devel] Why Qemu doesn't present L3 cache info for guest? Shannon Zhao
2016-08-25 12:46 ` Eduardo Habkost
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