From: Sean Christopherson <seanjc@google.com>
To: sashiko-reviews@lists.linux.dev
Cc: Oliver Upton <oupton@kernel.org>, Marc Zyngier <maz@kernel.org>,
kvmarm@lists.linux.dev, kvm@vger.kernel.org,
Aqib Faruqui <aqibaf@amazon.com>
Subject: Re: [PATCH v3 03/12] KVM: selftests: Pre-set threads affinity in hardware disable test when possible
Date: Fri, 31 Jul 2026 13:50:48 -0700 [thread overview]
Message-ID: <am0KqJOD-FiC9BXs@google.com> (raw)
In-Reply-To: <20260731201140.5AF0C1F00AC4@smtp.kernel.org>
+Aqib
On Fri, Jul 31, 2026, sashiko-bot@kernel.org wrote:
> > diff --git a/tools/testing/selftests/kvm/hardware_disable_test.c b/tools/testing/selftests/kvm/hardware_disable_test.c
> > index f088b4af3ccc7..b4edeadfa3f45 100644
> > --- a/tools/testing/selftests/kvm/hardware_disable_test.c
> > +++ b/tools/testing/selftests/kvm/hardware_disable_test.c
> > @@ -36,7 +36,9 @@ static void *run_vcpu(void *arg)
> > struct kvm_vcpu *vcpu = arg;
> > struct kvm_run *run = vcpu->run;
> >
> > +#ifndef _GNU_SOURCE
> > kvm_sched_setaffinity(0, sizeof(cpu_set_t), &threads_cpu_set);
> > +#endif
>
> [Severity: Low]
> Since the KVM selftests build system unconditionally defines _GNU_SOURCE,
> will this fallback code ever be reached?
>
> [ ... ]
>
> > @@ -80,22 +84,28 @@ static inline void check_join(pthread_t thread, void **retval)
> > static void run_test(u32 run)
> > {
> > struct kvm_vcpu *vcpu;
> > + pthread_attr_t attr;
> > struct kvm_vm *vm;
> > pthread_t threads[VCPU_NUM];
> > pthread_t throw_away;
> > void *b;
> > u32 i, j;
> >
> > + TEST_ASSERT_EQ(pthread_attr_init(&attr), 0);
> > +#ifdef _GNU_SOURCE
> > + TEST_ASSERT_EQ(pthread_attr_setaffinity_np(&attr, sizeof(cpu_set_t), &threads_cpu_set), 0);
> > +#endif
Aqib,
Do you happen to definitively know which is the "right" macro to check to detect
support for pthread_attr_setaffinity_np()? Belatedly, I saw that you used __GLIBC__
in a patch that ultimately wasn't applied[*].
I initially used __USE_GNU here, but then Sashiko yelled at me, so I switched to
_GNU_SOURCE based on Sashiko's suggestion, and now it's yelling at me again :-)
[*] https://lore.kernel.org/all/20250829142556.72577-4-aqibaf@amazon.com
> [Severity: Low]
> Could this break the build on systems using alternative libc implementations
> like musl?
>
> If _GNU_SOURCE is unconditionally defined by the Makefile but the libc
> doesn't provide pthread_attr_setaffinity_np, this might result in a
> compilation error rather than using the intended fallback.
>
> --
> Sashiko AI review · https://sashiko.dev/#/patchset/20260731195612.2697986-1-seanjc@google.com?part=3
next prev parent reply other threads:[~2026-07-31 20:50 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-31 19:56 [PATCH v3 00/12] KVM: selftests: Add more syscall wrappers, fix hardware_disable_test Sean Christopherson
2026-07-31 19:56 ` [PATCH v3 01/12] KVM: selftests: Add a KVM syscall wrapper for sched_setaffinity() Sean Christopherson
2026-07-31 19:56 ` [PATCH v3 02/12] KVM: selftests: Set threads CPU affinity before doing work in hardware disable test Sean Christopherson
2026-07-31 19:56 ` [PATCH v3 03/12] KVM: selftests: Pre-set threads affinity in hardware disable test when possible Sean Christopherson
2026-07-31 20:11 ` sashiko-bot
2026-07-31 20:50 ` Sean Christopherson [this message]
2026-07-31 19:56 ` [PATCH v3 04/12] KVM: selftests: Return the target CPU from pin_task_to_random_cpu() Sean Christopherson
2026-07-31 19:56 ` [PATCH v3 05/12] KVM: selftests: Extract picking of random CPU from cpu_set_t to separate API Sean Christopherson
2026-07-31 19:56 ` [PATCH v3 06/12] KVM: selftests: Affine threads to random CPUs in hardware disable test Sean Christopherson
2026-07-31 19:56 ` [PATCH v3 07/12] KVM: selftests: Drop unreachable, dead code from " Sean Christopherson
2026-07-31 19:56 ` [PATCH v3 08/12] KVM: selftests: Add KVM syscall wrapper for pthread_create() Sean Christopherson
2026-07-31 20:05 ` sashiko-bot
2026-07-31 19:56 ` [PATCH v3 09/12] KVM: selftests: Add KVM syscall wrappers for pthread_{cancel,join}() Sean Christopherson
2026-07-31 20:11 ` sashiko-bot
2026-07-31 19:56 ` [PATCH v3 10/12] KVM: selftests: Add helper APIs to cancel+join pthreads Sean Christopherson
2026-07-31 19:56 ` [PATCH v3 11/12] KVM: selftests: Add KVM syscall wrappers for pthread_{g,s}etaffinity_np() Sean Christopherson
2026-07-31 19:56 ` [PATCH v3 12/12] KVM: selftests: Clean up global constants in hardware disable test Sean Christopherson
2026-07-31 21:35 ` [PATCH v3 00/12] KVM: selftests: Add more syscall wrappers, fix hardware_disable_test Yosry Ahmed
2026-07-31 21:41 ` Sean Christopherson
2026-07-31 21:43 ` Yosry Ahmed
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