On 11/28/24 05:28, Amit Shah wrote: > From: Amit Shah <amit.shah@xxxxxxx> > > When Automatic IBRS is disabled, Linux flushed the RSB on every context > switch. This RSB flush is not necessary in software with the ERAPS > feature on Zen5+ CPUs that flushes the RSB in hardware on a context > switch (triggered by mov-to-CR3). > > Additionally, the ERAPS feature also tags host and guest addresses in > the RSB - eliminating the need for software flushing of the RSB on > VMEXIT. > > Disable all RSB flushing by Linux when the CPU has ERAPS. > > Feature mentioned in AMD PPR 57238. Will be resubmitted once APM is > public - which I'm told is imminent. There was a _lot_ of discussion about this. But all of that discussion seems to have been trimmed out and it seems like we're basically back to: "this is new hardware supposed to mitigate SpectreRSB, thus it mitigates SpectreRSB." Could we please summarize the previous discussions in the changelog? Otherwise, I fear it will be lost.
