linux-kernel - [PATCH 3/4] KVM: arm64: Use sanitized values in __check

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Date:   Wed,  1 Feb 2023 10:37:53 +0000
From:   Quentin Perret <qperret@...gle.com>
To:     Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Marc Zyngier <maz@...nel.org>,
        James Morse <james.morse@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Oliver Upton <oliver.upton@...ux.dev>,
        Zenghui Yu <yuzenghui@...wei.com>,
        Mark Brown <broonie@...nel.org>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kvmarm@...ts.linux.dev, kvmarm@...ts.cs.columbia.edu,
        kernel-team@...roid.com, Quentin Perret <qperret@...gle.com>
Subject: [PATCH 3/4] KVM: arm64: Use sanitized values in __check_override in nVHE

The nVHE EL2 code has access to sanitized values of certain idregs, so
use them directly from __check_override instead of the *_override
variants.

Signed-off-by: Quentin Perret <qperret@...gle.com>
---
 arch/arm64/include/asm/el2_setup.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h
index fb7d04b81033..1cc29960fcdb 100644
--- a/arch/arm64/include/asm/el2_setup.h
+++ b/arch/arm64/include/asm/el2_setup.h
@@ -196,6 +196,7 @@
 	__init_el2_nvhe_prepare_eret
 .endm
 
+#ifndef __KVM_NVHE_HYPERVISOR__
 // This will clobber tmp1 and tmp2, and expect tmp1 to contain
 // the id register value as read from the HW
 .macro __check_override idreg, fld, width, pass, fail, tmp1, tmp2
@@ -219,6 +220,19 @@
 	mrs	\tmp1, \idreg\()_el1
 	__check_override \idreg \fld 4 \pass \fail \tmp1 \tmp2
 .endm
+#else
+// This will clobber tmp
+.macro __check_override idreg, fld, width, pass, fail, tmp, ignore
+	ldr_l	\tmp, \idreg\()_el1_sys_val
+	ubfx	\tmp, \tmp, #\fld, #\width
+	cbnz	\tmp, \pass
+	b	\fail
+.endm
+
+.macro check_override idreg, fld, pass, fail, tmp, ignore
+	__check_override \idreg \fld 4 \pass \fail \tmp \ignore
+.endm
+#endif
 
 .macro finalise_el2_state
 	check_override id_aa64pfr0, ID_AA64PFR0_EL1_SVE_SHIFT, .Linit_sve_\@, .Lskip_sve_\@, x1, x2
-- 
2.39.1.456.gfc5497dd1b-goog