On Tue, Dec 01, 2020 at 02:43:49PM +0000, David Brazdil wrote: > > > > be just me, but if you agree please update so that it doesn't give remote > > > > idea that it is not valid on VHE enabled hardware. > > > > > > > > I was trying to run this on the hardware and was trying to understand the > > > > details on how to do that. > > > > > > I see what you're saying, but !CONFIG_ARM64_VHE isn't accurate either. The > > > option makes sense if: > > > 1) all cores booted in EL2 > > > == is_hyp_mode_available() > > > 2) ID_AA64MMFR1_EL1.VH=0 or !CONFIG_ARM64_VHE > > > == !is_kernel_in_hyp_mode() > > > > > > The former feels implied for KVM, the latter could be 'Valid if the kernel > > > is running in EL1'? WDYT? > > > > I reckon we can avoid the restriction if we instead add an early stub > > like with have for KASLR. That way we could parse the command line > > early, and if necessary re-initialize EL2 and drop to EL1 before the > > main kernel has to make any decisions about how to initialize things. > > That would allow us to have a more general kvm-arm.mode option where a > > single kernel Image could support: > > > > * "protected" mode on nVHE or VHE HW > > * "nvhe" mode on nVHE or VHE HW > > * "vhe" mode on VHE HW > > > > ... defaulting to VHE/nVHE modes depending on HW support. > > > > That would also be somewhat future-proof if we have to add other > > variants of protected mode in future, as we could extend the mode option > > with parameters for each mode. > > Agreed that 'mode' is a more future-proof flag and I would very much love to > have an option to force nVHE on VHE HW. I however expect that the early stub > would not be a trivial addition and would not want to get into that in this > series. Could we agree on 'protected' as the only supported value for the time > being? Sure, that works for me. Thanks, Mark.
