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From: Marc Zyngier <maz@kernel.org>
To: <kvmarm@lists.cs.columbia.edu>, <kvmarm@lists.linux.dev>,
	kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Quentin Perret <qperret@google.com>,
	Will Deacon <will@kernel.org>, Fuad Tabba <tabba@google.com>
Subject: [PATCH 03/17] arm64: Don't enable VHE for the kernel if OVERRIDE_HVHE is set
Date: Thu, 20 Oct 2022 10:07:13 +0100	[thread overview]
Message-ID: <20221020090727.3669908-4-maz@kernel.org> (raw)
In-Reply-To: <20221020090727.3669908-1-maz@kernel.org>

If the OVERRIDE_HVHE SW override is set (as a precursor of
the KVM_HVHE capability), do not enable VHE for the kernel
and drop to EL1 as if VHE was either disabled or unavailable.

Further changes will enable VHE at EL2 only, with the kernel
still running at EL1.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kernel/hyp-stub.S | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 2ee18c860f2a..0601cc9592bd 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -157,7 +157,15 @@ SYM_CODE_START_LOCAL(__finalise_el2)
 	tbnz	x1, #0, 1f
 
 	// Needs to be VHE capable, obviously
-	check_override id_aa64mmfr1 ID_AA64MMFR1_EL1_VH_SHIFT 2f 1f
+	check_override id_aa64mmfr1 ID_AA64MMFR1_EL1_VH_SHIFT 0f 1f
+
+0:	// Check whether we only want the hypervisor to run VHE, not the kernel
+	adr_l	x1, arm64_sw_feature_override
+	ldr	x2, [x1, FTR_OVR_VAL_OFFSET]
+	ldr	x1, [x1, FTR_OVR_MASK_OFFSET]
+	and	x2, x2, x1
+	ubfx	x2, x2, #ARM64_SW_FEATURE_OVERRIDE_HVHE, #4
+	cbz	x2, 2f
 
 1:	mov_q	x0, HVC_STUB_ERR
 	eret
-- 
2.34.1


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  parent reply	other threads:[~2022-10-20  9:08 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-20  9:07 [PATCH 00/17] KVM: arm64: Allow using VHE in the nVHE hypervisor Marc Zyngier
2022-10-20  9:07 ` [PATCH 01/17] arm64: Turn kaslr_feature_override into a generic SW feature override Marc Zyngier
2022-10-20  9:07 ` [PATCH 02/17] arm64: Add KVM_HVHE capability and has_hvhe() predicate Marc Zyngier
2023-06-01  7:01   ` Oliver Upton
2022-10-20  9:07 ` Marc Zyngier [this message]
2022-10-20  9:07 ` [PATCH 04/17] arm64: Prevent the use of is_kernel_in_hyp_mode() in hypervisor code Marc Zyngier
2022-10-20  9:07 ` [PATCH 05/17] arm64: Allow EL1 physical timer access when running VHE Marc Zyngier
2022-10-20  9:07 ` [PATCH 06/17] arm64: Use CPACR_EL1 format to set CPTR_EL2 when E2H is set Marc Zyngier
2022-10-20  9:07 ` [PATCH 07/17] KVM: arm64: Elide kern_hyp_va() in VHE-specific parts of the hypervisor Marc Zyngier
2022-10-20  9:07 ` [PATCH 08/17] KVM: arm64: Remove alternatives from sysreg accessors in VHE hypervisor context Marc Zyngier
2022-10-20  9:07 ` [PATCH 09/17] KVM: arm64: Key use of VHE instructions in nVHE code off ARM64_KVM_HVHE Marc Zyngier
2022-10-20  9:07 ` [PATCH 10/17] KVM: arm64: Force HCR_EL2.E2H when ARM64_KVM_HVHE is set Marc Zyngier
2022-10-20  9:07 ` [PATCH 11/17] KVM: arm64: Disable TTBR1_EL2 when using ARM64_KVM_HVHE Marc Zyngier
2022-10-20  9:07 ` [PATCH 12/17] KVM: arm64: Adjust EL2 stage-1 leaf AP bits when ARM64_KVM_HVHE is set Marc Zyngier
2022-10-20  9:07 ` [PATCH 13/17] KVM: arm64: Rework CPTR_EL2 programming for HVHE configuration Marc Zyngier
2022-10-20  9:07 ` [PATCH 14/17] KVM: arm64: Program the timer traps with VHE layout in hVHE mode Marc Zyngier
2022-10-20  9:07 ` [PATCH 15/17] KVM: arm64: Force HCR_E2H in guest context when ARM64_KVM_HVHE is set Marc Zyngier
2022-10-20  9:07 ` [PATCH 16/17] arm64: Allow arm64_sw.hvhe on command line Marc Zyngier
2022-10-20  9:07 ` [PATCH 17/17] KVM: arm64: Terrible timer hack for M1 with hVHE Marc Zyngier

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