From: Oliver Upton <oliver.upton@linux.dev>
To: kvmarm@lists.cs.columbia.edu
Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
maz@kernel.org, james.morse@arm.com, alexandru.elisei@arm.com,
suzuki.poulose@arm.com, will@kernel.org,
Oliver Upton <oliver.upton@linux.dev>
Subject: [PATCH v2 2/2] KVM: arm64: Reject 32bit user PSTATE on asymmetric systems
Date: Tue, 16 Aug 2022 19:25:54 +0000 [thread overview]
Message-ID: <20220816192554.1455559-3-oliver.upton@linux.dev> (raw)
In-Reply-To: <20220816192554.1455559-1-oliver.upton@linux.dev>
KVM does not support AArch32 EL0 on asymmetric systems. To that end,
prevent userspace from configuring a vCPU in such a state through
setting PSTATE.
It is already ABI that KVM rejects such a write on a system where
AArch32 EL0 is unsupported. Though the kernel's definition of a 32bit
system changed in commit 2122a833316f ("arm64: Allow mismatched
32-bit EL0 support"), KVM's did not.
Fixes: 2122a833316f ("arm64: Allow mismatched 32-bit EL0 support")
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
arch/arm64/kvm/guest.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 8c607199cad1..f802a3b3f8db 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -242,7 +242,7 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
u64 mode = (*(u64 *)valp) & PSR_AA32_MODE_MASK;
switch (mode) {
case PSR_AA32_MODE_USR:
- if (!system_supports_32bit_el0())
+ if (!kvm_supports_32bit_el0())
return -EINVAL;
break;
case PSR_AA32_MODE_FIQ:
--
2.37.1.595.g718a3a8f04-goog
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next prev parent reply other threads:[~2022-08-16 19:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-16 19:25 [PATCH v2 0/2] KVM: arm64: Uphold 64bit-only behavior on asymmetric systems Oliver Upton
2022-08-16 19:25 ` [PATCH v2 1/2] KVM: arm64: Treat PMCR_EL1.LC as RES1 " Oliver Upton
2022-08-16 19:25 ` Oliver Upton [this message]
2022-08-17 9:33 ` [PATCH v2 0/2] KVM: arm64: Uphold 64bit-only behavior " Marc Zyngier
2022-08-17 10:07 ` Marc Zyngier
2022-08-17 10:52 ` Alexandru Elisei
2022-08-17 10:56 ` Marc Zyngier
2022-08-17 15:13 ` Oliver Upton
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