On 15.02.2022 11:24, Borislav Petkov wrote:
On Mon, Feb 14, 2022 at 04:20:14PM -0800, Pawan Gupta wrote:
... we are calling tsx_clear_cpuid() unconditionally.
I know, that's why I asked...
> If those CPUs which support only disabling TSX through MSR_IA32_TSX_CTRL
> but don't have MSR_TSX_FORCE_ABORT - if those CPUs set
> X86_FEATURE_RTM_ALWAYS_ABORT too, then this should work.
... this^^.
IOW, what are you fixing here exactly?
Let's look at the two callsites of tsx_clear_cpuid():
1. tsx_init: that will do something on X86_FEATURE_RTM_ALWAYS_ABORT CPUs.
2. init_intel: that will get called when
tsx_ctrl_state == TSX_CTRL_RTM_ALWAYS_ABORT
But TSX_CTRL_RTM_ALWAYS_ABORT gets set only when
X86_FEATURE_RTM_ALWAYS_ABORT is set. I.e., the first case, in
tsx_init().
So, IIUC, you wanna fix the case where CPUs which set
X86_FEATURE_RTM_ALWAYS_ABORT but *don't* have MSR_TSX_FORCE_ABORT, those
CPUs should still disable TSX through MSR_IA32_TSX_CTRL.
Correct?
That is exactly what this patch is fixing. Please let me know if you
have any questions.
Thanks,
Pawan
