On 06/02/23 11:35, Manali Shukla wrote: > Currently, the hypervisor is able to inspect instruction based samples > from a guest and gather execution information. SEV-ES and SNP guests > can disallow the use of instruction based sampling by hypervisor by > enabling the PreventHostIBS feature for the guest. (More information > in Section 15.36.17 APM Volume 2) > > The MSR_AMD64_IBSFETCHCTL[IbsFetchEn] and MSR_AMD64_IBSOPCTL[IbsOpEn] > bits need to be disabled before VMRUN is called when PreventHostIBS > feature is enabled. If either of these bits are not 0, VMRUN will fail > with VMEXIT_INVALID error code. > > Because of an IBS race condition when disabling IBS, KVM needs to > indicate when it is in a PreventHostIBS window. Activate the window > based on whether IBS is currently active or inactive. > > Signed-off-by: Manali Shukla <manali.shukla@xxxxxxx> Looks good. Reviewed-by: Nikunj A Dadhania <nikunj@xxxxxxx>
