On Mon, Jan 18, 2021 at 09:45:26AM +0000, Marc Zyngier wrote: > diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S > index 59820f9b8522..bbab2148a2a2 100644 > --- a/arch/arm64/kernel/hyp-stub.S > +++ b/arch/arm64/kernel/hyp-stub.S > @@ -77,13 +77,24 @@ SYM_CODE_END(el1_sync) > SYM_CODE_START_LOCAL(mutate_to_vhe) > // Sanity check: MMU *must* be off > mrs x0, sctlr_el2 > - tbnz x0, #0, 1f > + tbnz x0, #0, 2f > > // Needs to be VHE capable, obviously > mrs x0, id_aa64mmfr1_el1 > ubfx x0, x0, #ID_AA64MMFR1_VHE_SHIFT, #4 > - cbz x0, 1f > + cbz x0, 2f > > + // Check whether VHE is disabled from the command line > + adr_l x1, id_aa64mmfr1_val > + ldr x0, [x1] > + adr_l x1, id_aa64mmfr1_mask > + ldr x1, [x1] > + ubfx x0, x0, #ID_AA64MMFR1_VHE_SHIFT, #4 > + ubfx x1, x1, #ID_AA64MMFR1_VHE_SHIFT, #4 > + cbz x1, 1f > + and x0, x0, x1 > + cbz x0, 2f > +1:
I can see the advantage here in separate id_aa64mmfr1_val/mask but we could use some asm offsets here and keep the pointer indirection simpler in C code. You'd just need something like 'adr_l mmfr1_ovrd + VAL_OFFSET'. Anyway, if you have a strong preference for the current approach, leave it as is. -- Catalin _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
