Haren Myneni <ha...@linux.ibm.com> writes: > On Tue, 2021-11-30 at 10:25 +1100, Michael Ellerman wrote: >> Nicholas Piggin <npig...@gmail.com> writes: >> > Excerpts from Cédric Le Goater's message of November 26, 2021 5:13 >> > pm: >> > > On 11/26/21 06:21, Nicholas Piggin wrote: >> > > > KVM does not support VAS so guests always print a useless error >> > > > on boot >> > > > >> > > > vas: HCALL(398) error -2, query_type 0, result buffer >> > > > 0x57f2000 >> > > > >> > > > Change this to only print the message if the error is not >> > > > H_FUNCTION. >> > > >> > > Just being curious, why is it even called since "ibm,compression" >> > > should >> > > not be exposed in the DT ? >> > >> > It looks like vas does not test for it. I guess in theory there can >> > be >> > other functions than compression implemented as an accelerator. >> > Maybe >> > that's why? >> >> Yeah I guess, or it's just not structured that well. The vas platform >> code is a bit awkward, it's there to support drivers, but it's not >> actually driver code. >> >> I think we can probably rework it so the vas code does nothing until >> a >> driver calls in to it. >> >> eg. something like below. > > Correct, Even though NXGZIP is the only usage right now, VAS is > accelerator switchboard which should support other coprocessor types > such as GZIP and 842 or SW type solutions such as fast thread wakeup > and fast memory copy. > > So can we leave VAS initialization separate from drivers and use some > feature such as FW_FEATURE_LPAR to differentiate from KVM guests?
FW_FEATURE_LPAR is true on KVM guests as well. As Tyrel pointed out, you should be looking for "hcall-vas" in "ibm,hypertas-functions" and setting a new FW_FEATURE_VAS based on that. Then use that to gate the vas init routine. cheers
