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From: Wei-Lin Chang <weilin.chang@arm.com>
To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
	linux-kernel@vger.kernel.org
Cc: Marc Zyngier <maz@kernel.org>, Oliver Upton <oupton@kernel.org>,
	Fuad Tabba <fuad.tabba@linux.dev>,
	Joey Gouly <joey.gouly@arm.com>,
	Steffen Eiden <seiden@linux.ibm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Sascha Bischoff <Sascha.Bischoff@arm.com>,
	Ben Horgan <ben.horgan@arm.com>,
	Lorenzo Pieralisi <lpieralisi@kernel.org>,
	Thomas Huth <thuth@redhat.com>,
	James Clark <james.clark@linaro.org>,
	Mark Brown <broonie@kernel.org>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Wei-Lin Chang <weilin.chang@arm.com>
Subject: [PATCH v1 1/3] KVM: arm64: nv: Don't advertise FEAT_LPA2 for guest stage-1
Date: Wed,  9 Sep 2026 23:20:13 +0100	[thread overview]
Message-ID: <20260909222015.3046432-2-weilin.chang@arm.com> (raw)
In-Reply-To: <20260909222015.3046432-1-weilin.chang@arm.com>

There is no FEAT_LPA2 support for NV guests as of now, but we missed
limiting it for the non-stage-2 granule size fields (TGRAN4, TGRAN16) in
ID_AA64MMFR0_EL1. Add the sanitisation.

Signed-off-by: Wei-Lin Chang <weilin.chang@arm.com>
---
 arch/arm64/kvm/nested.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c
index 3c4fc566eafc..1fd98117df23 100644
--- a/arch/arm64/kvm/nested.c
+++ b/arch/arm64/kvm/nested.c
@@ -1731,6 +1731,19 @@ u64 limit_nv_id_reg(struct kvm *kvm, u32 reg, u64 val)
 		/* Hide CNTPOFF if present */
 		val = ID_REG_LIMIT_FIELD_ENUM(val, ID_AA64MMFR0_EL1, ECV, IMP);
 
+		/* NV does not support FEAT_LPA2. */
+		if (SYS_FIELD_GET(ID_AA64MMFR0_EL1, TGRAN4, val) ==
+		    ID_AA64MMFR0_EL1_TGRAN4_52_BIT) {
+			val &= ~ID_AA64MMFR0_EL1_TGRAN4;
+			val |= SYS_FIELD_PREP_ENUM(ID_AA64MMFR0_EL1, TGRAN4, IMP);
+		}
+
+		if (SYS_FIELD_GET(ID_AA64MMFR0_EL1, TGRAN16, val) ==
+		    ID_AA64MMFR0_EL1_TGRAN16_52_BIT) {
+			val &= ~ID_AA64MMFR0_EL1_TGRAN16;
+			val |= SYS_FIELD_PREP_ENUM(ID_AA64MMFR0_EL1, TGRAN16, IMP);
+		}
+
 		/* Disallow unsupported S2 page sizes */
 		switch (PAGE_SIZE) {
 		case SZ_64K:
-- 
2.43.0


  reply	other threads:[~2026-09-09 22:20 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-09 22:20 [PATCH v1 0/3] KVM: arm64: Properly advertise !FEAT_LPA2 for NV Wei-Lin Chang
2026-09-09 22:20 ` Wei-Lin Chang [this message]
2026-09-11  9:08   ` [PATCH v1 1/3] KVM: arm64: nv: Don't advertise FEAT_LPA2 for guest stage-1 Marc Zyngier
2026-09-09 22:20 ` [PATCH v1 2/3] arm64: sysreg: Add TCR_EL2 to sysreg infrastructure Wei-Lin Chang
2026-09-10 11:54   ` Mark Brown
2026-09-09 22:20 ` [PATCH v1 3/3] KVM: arm64: Convert TCR_EL2 to config-driven sanitisation Wei-Lin Chang
2026-09-11  9:04   ` Marc Zyngier

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