[PATCH v4 14/21] arm64: Honor VHE being disabled from the command-line

[Marc Zyngier]

Finally we can check whether VHE is disabled on the command line,
and not enable it if that's the user's wish.

Signed-off-by: Marc Zyngier <m...@kernel.org>
---
 arch/arm64/kernel/hyp-stub.S | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

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:
        // Engage the VHE magic!
        mov_q   x0, HCR_HOST_VHE_FLAGS
        msr     hcr_el2, x0
@@ -152,7 +163,7 @@ skip_spe:
        orr     x0, x0, x1
        msr     spsr_el1, x0
 
-1:     eret
+2:     eret
 SYM_CODE_END(mutate_to_vhe)
 
 .macro invalid_vector  label
-- 
2.29.2