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

Marc Zyngier
2021-01-18T21:38:53Z

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 <maz@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