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From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu
Cc: kernel-team@android.com,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH 13/17] arm64: Honor VHE being disabled from the command-line
Date: Mon, 28 Dec 2020 10:49:54 +0000
Message-ID: <20201228104958.1848833-14-maz@kernel.org> (raw)
In-Reply-To: <20201228104958.1848833-1-maz@kernel.org>

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 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
-- 
2.29.2

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Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-28 10:49 [PATCH 00/17] arm64: Early CPU feature override, and an application to VHE Marc Zyngier
2020-12-28 10:49 ` [PATCH 01/17] arm64: Fix labels in el2_setup macros Marc Zyngier
2020-12-28 10:49 ` [PATCH 02/17] arm64: Fix outdated TCR setup comment Marc Zyngier
2020-12-28 10:49 ` [PATCH 03/17] arm64: Turn the MMU-on sequence into a macro Marc Zyngier
2020-12-28 10:49 ` [PATCH 04/17] arm64: Provide an 'upgrade to VHE' stub hypercall Marc Zyngier
2021-01-04 23:39   ` Jing Zhang
2021-01-05  8:24     ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 05/17] arm64: Initialise as nVHE before switching to VHE Marc Zyngier
2020-12-28 10:49 ` [PATCH 06/17] arm64: Move VHE-specific SPE setup to mutate_to_vhe() Marc Zyngier
2020-12-28 10:49 ` [PATCH 07/17] arm64: Simplify init_el2_state to be non-VHE only Marc Zyngier
2020-12-28 10:49 ` [PATCH 08/17] arm64: Move SCTLR_EL1 initialisation to EL-agnostic code Marc Zyngier
2020-12-28 10:49 ` [PATCH 09/17] arm64: cpufeature: Add global feature override facility Marc Zyngier
2020-12-28 10:49 ` [PATCH 10/17] arm64: Extract early FDT mapping from kaslr_early_init() Marc Zyngier
2020-12-28 10:49 ` [PATCH 11/17] arm64: cpufeature: Add an early command-line cpufeature override facility Marc Zyngier
2020-12-28 10:49 ` [PATCH 12/17] arm64: Allow ID_AA64MMFR1_EL1.VH to be overridden from the command line Marc Zyngier
2020-12-28 10:49 ` Marc Zyngier [this message]
2020-12-28 10:49 ` [PATCH 14/17] arm64: Add an aliasing facility for the idreg override Marc Zyngier
2020-12-28 10:49 ` [PATCH 15/17] arm64: Make kvm-arm.mode={nvhe, protected} an alias of id_aa64mmfr1.vh=0 Marc Zyngier
2020-12-28 10:49 ` [PATCH 16/17] KVM: arm64: Document HVC_VHE_RESTART stub hypercall Marc Zyngier
2020-12-28 10:49 ` [PATCH 17/17] arm64: Move "nokaslr" over to the early cpufeature infrastructure Marc Zyngier
2020-12-29 19:27 ` [PATCH 00/17] arm64: Early CPU feature override, and an application to VHE Marc Zyngier

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