[13/17] arm64: Honor VHE being disabled from the command-line

Commit Message

Marc Zyngier Dec. 28, 2020, 10:49 a.m. UTC

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 <[e-mail]>
---
 arch/arm64/kernel/hyp-stub.S | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

Patch

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 5d19cba654c7..d8ca1a85b725 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -80,13 +80,24 @@  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
@@ -150,7 +161,7 @@  skip_spe:
 	orr	x0, x0, x1
 	msr	spsr_el1, x0
 
-1:	eret
+2:	eret
 SYM_CODE_END(mutate_to_vhe)
 
 .macro invalid_vector	label