On Thu, Feb 29, 2024 at 06:24:37PM +0000, Marc Zyngier wrote: > On Thu, 29 Feb 2024 17:37:08 +0000, Oliver Upton <oliver.upton@xxxxxxxxx> wrote: > > I was wondering if there was a way to surface these screw-ups at compile > > time, but there's nothing elegant that comes to mind. Guess we need to > > be very careful reviewing "nVHE" changes going forward. > > My take on this is that there should hardly be any read_sysreg_s() in > the KVM code at all. We should always use read_sysreg_el*() so that > there is no ambiguity about the state we're dealing with (that's, of > course, only valid for registers that have both an EL1 and an EL2 > counterpart -- registers that are shared across ELs must still use the > read_sysreg_s() accessor). Agreed, I was thinking something along the lines of an accessor that expresses our intent to access EL2 state, but you can't really add compile-time assertions behind that. Perhaps it makes the code slightly more readable, but at that point we're just rolling a turd in glitter. > It would also free the drive-by hacker from having to understand the > subtleties of the E2H redirection. The macros do the right thing > everywhere (they are context aware), and they should be the first port > of call. Right, I think the mechanism for poking at true EL1 state achieves a good abstraction. > > Reviewed-by: Oliver Upton <oliver.upton@xxxxxxxxx> > > Thanks. What should we do about it? Fix for 6.8, or part of the 6.9 > drop? hVHE+tracing is a pretty niche thing, and I don't have any other > fix for the time being... Ah, we are pretty late in the cycle, I should've asked :) Happy to pick this up for 6.9 then. -- Thanks, Oliver
