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From: Fuad Tabba <tabba@google.com>
To: Marc Zyngier <maz@kernel.org>, Oliver Upton <oupton@kernel.org>,
	 linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
	 linux-kernel@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,  Joey Gouly <joey.gouly@arm.com>,
	Steffen Eiden <seiden@linux.ibm.com>,
	 Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	 Vincent Donnefort <vdonnefort@google.com>,
	Sascha Bischoff <Sascha.Bischoff@arm.com>,
	tabba@google.com
Subject: [PATCH 2/7] KVM: arm64: Unconditionally set IL for injected undefined exceptions
Date: Sun, 14 Jun 2026 17:33:31 +0100	[thread overview]
Message-ID: <20260614163336.3490925-3-tabba@google.com> (raw)
In-Reply-To: <20260614163336.3490925-1-tabba@google.com>

inject_undef64() derives IL from the triggering trap's instruction
length (kvm_vcpu_trap_il_is32bit()), but the IL of the injected
exception is fixed by its EC, not by the triggering instruction. The
architecture mandates IL=1 for EC=0 (Unknown) unconditionally, so the
conditional is wrong. The undef-injection paths are not reached from
16-bit instructions, so there is no functional change today, but the
logic should not rely on that.

Set ESR_ELx_IL unconditionally.

Fixes: aa8eff9bfbd5 ("arm64: KVM: fault injection into a guest")
Signed-off-by: Fuad Tabba <tabba@google.com>
---
 arch/arm64/kvm/inject_fault.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
index 89982bd3345f..9dfae1bcdf99 100644
--- a/arch/arm64/kvm/inject_fault.c
+++ b/arch/arm64/kvm/inject_fault.c
@@ -170,14 +170,7 @@ void kvm_inject_sync(struct kvm_vcpu *vcpu, u64 esr)
 
 static void inject_undef64(struct kvm_vcpu *vcpu)
 {
-	u64 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT);
-
-	/*
-	 * Build an unknown exception, depending on the instruction
-	 * set.
-	 */
-	if (kvm_vcpu_trap_il_is32bit(vcpu))
-		esr |= ESR_ELx_IL;
+	u64 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT) | ESR_ELx_IL;
 
 	kvm_inject_sync(vcpu, esr);
 }
-- 
2.54.0.1136.gdb2ca164c4-goog



  parent reply	other threads:[~2026-06-14 16:33 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-14 16:33 [PATCH 0/7] KVM: arm64: Fix missing ESR_ELx.IL in syndrome injection Fuad Tabba
2026-06-14 16:33 ` [PATCH 1/7] KVM: arm64: Set ESR_ELx.IL for injected undefined exceptions at EL2 Fuad Tabba
2026-06-14 16:33 ` Fuad Tabba [this message]
2026-06-14 16:33 ` [PATCH 3/7] KVM: arm64: Unconditionally set IL for injected abort exceptions Fuad Tabba
2026-06-14 16:33 ` [PATCH 4/7] KVM: arm64: Set IL for injected FPAC exceptions during ERET emulation Fuad Tabba
2026-06-14 16:33 ` [PATCH 5/7] KVM: arm64: Set IL for emulated SError injection Fuad Tabba
2026-06-14 16:33 ` [PATCH 6/7] KVM: arm64: Set IL for nested " Fuad Tabba
2026-06-14 16:33 ` [PATCH 7/7] KVM: arm64: Set IL in fake ESR for pKVM memory sharing exit Fuad Tabba

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