From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id CDECA3EDAB0 for ; Fri, 6 Mar 2026 18:24:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772821453; cv=none; b=ASFXoN+beNKOUyBkJ+vLaKr5N0+98mv3AjNCU2HR/E8zYpcoQeXgllTiqrlZMxcKKVM86VUYYhYjT/a1G11/jCGGbFZFo3G7FKaZNcDtg0ZJxSsi4ouXdbQyDGJVOzKae2uEN7sqOkUIZQufJJ/lMdTPOkAqXwrNvceayiwjfrw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772821453; c=relaxed/simple; bh=yVPdRQVi/AKh+AGMAvDMpn+qRz4VOLLUfkb/iGtLw8k=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=WSYy+l8pydzj8MOu1PoLgHcvx3snCpFeFWWpzvtuE6qWH/QKs7zxW3uPLhFhOrp8IBGTaBFd6a5Xc5UYozvj204S3KYkQJZdf4m60yagBbMSM+tYCt1zKJj6qTEw7Z2uNgS9jEVuInZR70o3QQ1a+JT82kAoU3VFC8TKU6ZtwA4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0B2511516; Fri, 6 Mar 2026 10:24:05 -0800 (PST) Received: from [10.1.196.96] (eglon.cambridge.arm.com [10.1.196.96]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C65FD3F7BD; Fri, 6 Mar 2026 10:24:09 -0800 (PST) Message-ID: Date: Fri, 6 Mar 2026 18:24:09 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 2/2] arm_mpam: Disable preemption when making accesses to fake MSC in kunit test To: Ben Horgan Cc: reinette.chatre@intel.com, fenghuay@nvidia.com, gshan@redhat.com, zengheng4@huawei.com, jonathan.cameron@huawei.com, tan.shaopeng@jp.fujitsu.com, linux-kernel@vger.kernel.org References: <20260227110314.4038066-1-ben.horgan@arm.com> <20260227110314.4038066-3-ben.horgan@arm.com> Content-Language: en-GB From: James Morse In-Reply-To: <20260227110314.4038066-3-ben.horgan@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Ben, On 27/02/2026 11:03, Ben Horgan wrote: > Accesses to MSC must be made from a cpu that is affine to that MSC and the > driver checks this in __mpam_write_reg() using smp_processor_id(). A fake > in-memory MSC is used for testing. When using that, it doesn't matter which > cpu we access it from but calling smp_processor_id() from a preemptible > context gives warnings when running with CONFIG_DEBUG_PREEMPT. Bah! > Add a test helper that wraps mpam_reset_msc_bitmap() with preemption > disabled to ensure all (fake) MSC accesses are made with preemption > disabled. > diff --git a/drivers/resctrl/test_mpam_devices.c b/drivers/resctrl/test_mpam_devices.c > index 3e8d564a0c64..75bd41bcc395 100644 > --- a/drivers/resctrl/test_mpam_devices.c > +++ b/drivers/resctrl/test_mpam_devices.c > @@ -322,6 +322,14 @@ static void test_mpam_enable_merge_features(struct kunit *test) > mutex_unlock(&mpam_list_lock); > } > > +static void __test_mpam_reset_msc_bitmap(struct mpam_msc *msc, u16 reg, u16 wd) > +{ > + /* Avoid warnings when running with CONFIG_DEBUG_PREEMPT */ > + guard(preempt)(); > + > + mpam_reset_msc_bitmap(msc, reg, wd); > +} Reviewed-by: James Morse Thanks, James