linux-kernel - Re: [PATCH v11 33/46] KVM: selftests: Hyper-V PV IPI selftest

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Date:   Wed, 19 Oct 2022 22:08:56 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Vitaly Kuznetsov <vkuznets@...hat.com>
Cc:     kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Michael Kelley <mikelley@...rosoft.com>,
        Siddharth Chandrasekaran <sidcha@...zon.de>,
        Yuan Yao <yuan.yao@...ux.intel.com>,
        Maxim Levitsky <mlevitsk@...hat.com>,
        linux-hyperv@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v11 33/46] KVM: selftests: Hyper-V PV IPI selftest

On Tue, Oct 04, 2022, Vitaly Kuznetsov wrote:
> +static void *vcpu_thread(void *arg)
> +{
> +	struct kvm_vcpu *vcpu = (struct kvm_vcpu *)arg;
> +	struct ucall uc;
> +	int old;
> +	int r;
> +	unsigned int exit_reason;
> +
> +	r = pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &old);
> +	TEST_ASSERT(r == 0,
> +		    "pthread_setcanceltype failed on vcpu_id=%u with errno=%d",
> +		    vcpu->id, r);
> +
> +	vcpu_run(vcpu);
> +	exit_reason = vcpu->run->exit_reason;
> +
> +	TEST_ASSERT(exit_reason == KVM_EXIT_IO,
> +		    "vCPU %u exited with unexpected exit reason %u-%s, expected KVM_EXIT_IO",
> +		    vcpu->id, exit_reason, exit_reason_str(exit_reason));
> +
> +	if (get_ucall(vcpu, &uc) == UCALL_ABORT) {
> +		TEST_ASSERT(false,
> +			    "vCPU %u exited with error: %s.\n",
> +			    vcpu->id, (const char *)uc.args[0]);

REPORT_GUEST_ASSERT_N()?

> +	}
> +
> +	return NULL;
> +}
> +
> +static void cancel_join_vcpu_thread(pthread_t thread, struct kvm_vcpu *vcpu)
> +{
> +	void *retval;
> +	int r;
> +
> +	r = pthread_cancel(thread);
> +	TEST_ASSERT(r == 0,

!r is generally preferred over "r == 0"

> +		    "pthread_cancel on vcpu_id=%d failed with errno=%d",
> +		    vcpu->id, r);

Do you happen to know if errno is preserved?  I.e. if TEST_ASSERT()'s print of
errno will capture the right errno?  If so, this and the pthread_join() assert
can be:

	TEST_ASSERT(!r, pthread_cancel() failed on vcpu_id=%d, vcpu->id);

> +
> +	r = pthread_join(thread, &retval);
> +	TEST_ASSERT(r == 0,
> +		    "pthread_join on vcpu_id=%d failed with errno=%d",
> +		    vcpu->id, r);

...

> +	r = pthread_create(&threads[0], NULL, vcpu_thread, vcpu[1]);
> +	TEST_ASSERT(r == 0,
> +		    "pthread_create halter failed errno=%d", errno);
> +
> +	r = pthread_create(&threads[1], NULL, vcpu_thread, vcpu[2]);
> +	TEST_ASSERT(r == 0,
> +		    "pthread_create halter failed errno=%d", errno);

Similar comments as above.

> +
> +	while (true) {
> +		r = _vcpu_run(vcpu[0]);
> +		exit_reason = vcpu[0]->run->exit_reason;
> +
> +		TEST_ASSERT(!r, "vcpu_run failed: %d\n", r);

Why use _vcpu_run() with a manual assert?  Won't the vanilla vcpu_run() do what
you want?