On Tue, Apr 16, 2024 at 11:24:16AM -0700, Reinette Chatre wrote: >Hi Isaku, > >On 2/26/2024 12:26 AM, isaku.yamahata@xxxxxxxxx wrote: >> From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx> >> >> Because debug store is clobbered, restore it on TD exit. >> > >I am trying to understand why this is needed and finding a few >places that seem to indicate that this is not needed. > >For example, in the TX base spec, section 15.2 "On-TD Performance >Monitoring", subsection "15.2.1 Overview": > * IA32_DS_AREA MSR is context-switched across TD entry and exit transitions. > >To confirm I peeked at the TDX module code and found (if I understand this >correctly) that IA32_DS_AREA is saved on TD entry (see [1]) and restored on >TD exit (see [2]). Hi Reinette, You are right. I asked TDX module to preserve IA32_DS_AREA across TD transitions and they made this change. So, this patch can be dropped now.
