F5F Stay Refreshed Hardware Desktop QEMU Virtual Machine Manager uses L3 cache sharing for the 7950x3d platform

QEMU Virtual Machine Manager uses L3 cache sharing for the 7950x3d platform

QEMU Virtual Machine Manager uses L3 cache sharing for the 7950x3d platform

G
GodPlayer312
Member
60
03-09-2023, 11:42 PM
#1
Hello, your setup involves running Windows 11 inside Linux via QEMU and VM Manager. You're seeing physical cores 0-7 sharing an L3 cache, but the guest OS reports each core as separate with its own 16MB cache. Your attempts to adjust CPU settings haven't yielded consistent results. The "Resource control is not supported" error when using cache tuning or passthrough mode suggests limitations in your host's capabilities. The Ryzen 7950X3D supports this kind of configuration, but it requires specific hardware features like full L3 cache sharing and certain BIOS settings. When purchasing CPUs for such scenarios, look for models with dedicated L3 cache per core and robust memory management support.
G
GodPlayer312
03-09-2023, 11:42 PM #1

Hello, your setup involves running Windows 11 inside Linux via QEMU and VM Manager. You're seeing physical cores 0-7 sharing an L3 cache, but the guest OS reports each core as separate with its own 16MB cache. Your attempts to adjust CPU settings haven't yielded consistent results. The "Resource control is not supported" error when using cache tuning or passthrough mode suggests limitations in your host's capabilities. The Ryzen 7950X3D supports this kind of configuration, but it requires specific hardware features like full L3 cache sharing and certain BIOS settings. When purchasing CPUs for such scenarios, look for models with dedicated L3 cache per core and robust memory management support.

S
SUPERCAKE333
Junior Member
5
03-10-2023, 04:50 AM
#2
I think I figured it out myself now. There was a mistake in my setup that caused the same error message before. I forgot to include the cache tune setting in the config when testing. The issue was likely in the cpu section—specifically missing lines. I added these two entries:

<cpu mode="host-passthrough" check="none" migratable="on">
<topology sockets="1" dies="1" cores="8" threads="2"/>
<cache mode="passthrough"/>
<feature policy="require" name="topoext"/>
</cpu>

Now it should work. Problem solved! Smile
S
SUPERCAKE333
03-10-2023, 04:50 AM #2

I think I figured it out myself now. There was a mistake in my setup that caused the same error message before. I forgot to include the cache tune setting in the config when testing. The issue was likely in the cpu section—specifically missing lines. I added these two entries:

<cpu mode="host-passthrough" check="none" migratable="on">
<topology sockets="1" dies="1" cores="8" threads="2"/>
<cache mode="passthrough"/>
<feature policy="require" name="topoext"/>
</cpu>

Now it should work. Problem solved! Smile