vcpu_allowed_register_width() checks if all the VCPUs are either
all 32bit or all 64bit. Since the checking is done even for vCPUs
that are not initialized (KVM_ARM_VCPU_INIT has not been done) yet,
the non-initialized vCPUs are erroneously treated as 64bit vCPU,
which causes the function to incorrectly detect a mixed-width VM.
Fix vcpu_allowed_register_width() to skip the check for vCPUs that
are not initialized yet.
Fixes: 66e94d5cafd4 ("KVM: arm64: Prevent mixed-width VM creation")
Signed-off-by: Reiji Watanabe <reijiw@xxxxxxxxxx>
---
arch/arm64/kvm/reset.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 426bd7fbc3fd..ef78bbc7566a 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -180,8 +180,19 @@ static bool vcpu_allowed_register_width(struct kvm_vcpu *vcpu)
if (kvm_has_mte(vcpu->kvm) && is32bit)
return false;
+ /*
+ * Make sure vcpu->arch.target setting is visible from others so
+ * that the width consistency checking between two vCPUs is done
+ * by at least one of them at KVM_ARM_VCPU_INIT.
+ */
+ smp_mb();
+
/* Check that the vcpus are either all 32bit or all 64bit */
kvm_for_each_vcpu(i, tmp, vcpu->kvm) {
+ /* Skip if KVM_ARM_VCPU_INIT is not done for the vcpu yet */
+ if (tmp->arch.target == -1)
+ continue;
+
if (vcpu_has_feature(tmp, KVM_ARM_VCPU_EL1_32BIT) != is32bit)
return false;
}
base-commit: df0cc57e057f18e44dac8e6c18aba47ab53202f9
--
2.34.1.575.g55b058a8bb-goog
