Re: [PATCH v2] KVM: arm64: selftests: Check ID regs are immutable after a failed run

Mark Brown <[email protected]> Wed, 5 Aug 2026 15:15:23 +0100

Newsgroups	dev.linux.lists.kvmarm,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-kernel
Message-ID	<[email protected]>

On Wed, Aug 05, 2026 at 07:47:40AM +0100, Fuad Tabba wrote:
> Add a set_id_regs case covering ID register immutability when a vCPU's
> first KVM_RUN fails after finalization but before
> KVM_ARCH_FLAG_HAS_RAN_ONCE is set. The test provokes such a failure with
> a PMUv3-enabled vCPU whose PMU is left uninitialized, then checks that
> KVM_SET_ONE_REG on the feature and implementation ID registers, and
> KVM_CREATE_DEVICE for a vGIC, are all rejected with -EBUSY.

> +	/*
> +	 * A PMUv3 vCPU left without PMU init is rejected by
> +	 * kvm_arm_pmu_v3_enable(), which runs after sysreg finalization.
> +	 */
> +	r = _vcpu_run(vcpu);
> +	TEST_ASSERT(r < 0 && errno == EINVAL,
> +		    "first KVM_RUN should fail post-finalization: r=%d errno=%d",
> +		    r, errno);

As mentioned on the prior version TEST_ASSERT() is not good practice for
something reporting individual kselftest results, and while there's a
bunch of bad practice in this file we do also have some attempts at
doing better (although not currently entirely successful).

Otherwise this looks fine so I guess

Acked-by: Mark Brown <[email protected]>

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