Re: [PATCH] cpu_map: Add more -noTSX x86 CPU models (Sapphire and Granite rapids)
On Mon, Jun 02, 2025 at 01:19:29 +0200, Hector Cao wrote:
Several Intel CPU models with TSX technology (HLE & RTM features)
are
affected by the vulnerability TAA[1]. One of the mitigation methods
for TAA is to disable TSX support on the host system. For that purpose,
in 2021, Intel published a microcode update to disable TSX. Linux kernel
also disables TSX globally by default. Even though TSX can be activated via
the kernel command line (tsx=on), many Linux distributions stick with
this default behavior and have TSX disabled. This makes existing CPU
models that have HLE and RTM enabled not correctly detected by
libvirt.
Can you describe the issue in more details? Especially where libvirt
incorrectly detects CPU models because of this?
This commit adds 2 remaining -noTSX models:
- SapphireRapids-noTSX
- GraniteRapids-noTSX
QEMU switched away from adding suffixes to CPU models and just adds a
new version for a CPU model in case it needs to be updated. There's no
point adding these models to libvirt. Any CPU model that would only
exist in libvirt would not be directly usable anyway and would have to
be translated to another CPU model.
Jirka