Re: [PATCH v3 0/4] Distinguish between variants of IBPB

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, Aug 23 2024 at 11:53, Jim Mattson wrote:

> Prior to Zen4, AMD's IBPB did not flush the RAS (or, in Intel
> terminology, the RSB). Hence, the older version of AMD's IBPB was not
> equivalent to Intel's IBPB. However, KVM has been treating them as
> equivalent, synthesizing Intel's CPUID.(EAX=7,ECX=0):EDX[bit 26] on any
> platform that supports the synthetic features X86_FEATURE_IBPB and
> X86_FEATURE_IBRS.
>
> Equivalence also requires a previously ignored feature on the AMD side,
> CPUID Fn8000_0008_EBX[IBPB_RET], which is enumerated on Zen4.
>
> v3: Pass through IBPB_RET from hardware to userspace. [Tom]
>     Derive AMD_IBPB from X86_FEATURE_SPEC_CTRL rather than
>     X86_FEATURE_IBPB. [Tom]
>     Clarify semantics of X86_FEATURE_IBPB.
>
> v2: Use IBPB_RET to identify semantic equality. [Venkatesh]

Assuming this goes through the KVM tree:

Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>




[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]

  Powered by Linux