Re: [PATCH v4 14/21] arm64: Honor VHE being disabled from the command-line
flat view
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2021-01-23 14:09:06
Also in:
kvmarm, lkml
On Mon, Jan 18, 2021 at 09:45:26AM +0000, Marc Zyngier wrote:
quoted hunk ↗ jump to hunk
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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel