On Wed, Aug 20, 2025 at 11:02:11PM +0100, Marc Zyngier wrote: > Mark Brown <broonie@xxxxxxxxxx> wrote: > > As per DDI 0487 RWTXBY we need to manage PSTATE.EXLOCK when entering an > Nit: please use an underscore between the type of a statement and its > "name", as it makes it a bit more readable (R_WTXBY). Updated as you request. I have seen both usages - the non _ version plays nicer with searching the PDF to find the rules since you can just copy it directly into a PDF viewer. > > + // EL, or to GCSCR_ELx.EXLOCKEN for an exception to the same > > + // exception level. See ARM DDI 0487 RWTXBY, D.1.3.2 in K.a. > > + new |= enter_exception64_gcs(vcpu, mode, target_mode); > > + > > new |= PSR_D_BIT; > > new |= PSR_A_BIT; > > new |= PSR_I_BIT; > But that's not the only case where we have to deal with EXLOCK, is it? > What of ERET and its PAuth variants? R_TYTWB says: > <quote> > If in AArch64 state, any of the following situations can cause an > illegal exception return: > > [...] > > - If the Effective value of GCSCR_ELx.EXLOCKEN is 1 and PSTATE.EXLOCK > is 0, the execution of an exception return instruction to return to > the current Exception level ELx. > </quote> > My reading of the spec is that this needs handling. Am I right in thinking that this handling is needed for the NV case only?
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