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 BB4F624BD1A; Mon, 20 Oct 2025 15:15:02 +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=1760973305; cv=none; b=T0sRvy92XA+Sew8uxfpR4dppGVFmyrX1zu1Q0N0o7PYFIWf0GmsQDmHt0vzggrtaBxnNZdKG1iifQeQg4VMNK205yvSruSHn49ndIurERDQvNaZ1g0NPIbZ3F+M9vte//uXeBaxmrvrlcFoCSzduQ7YvINPpiKtvPN+V6aPamd4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760973305; c=relaxed/simple; bh=lpAJKs5aEfXOBaNfgX43lajmP/dejGOz35JJ3WbL3fg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=AjYicODAEFeA7yZzwQF3a5CBZm6MMMqAPdhAaYON2uoCfp4s7UmLA2xuLhnoBrsy83addf0Ol8cCVzy5ByWZXRWdU21n26Gun899x54/sF3lnCnpEz2MfHF3ISCJLkxn/zr3ZN99e3spJmILz1WMKZ0Ewk7suKGBDDRqcsUbz/s= 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 629F91063; Mon, 20 Oct 2025 08:14:48 -0700 (PDT) Received: from [10.1.196.46] (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id ABB853F66E; Mon, 20 Oct 2025 08:14:51 -0700 (PDT) Message-ID: <0d620641-6142-432d-9c25-a35b37f8bde6@arm.com> Date: Mon, 20 Oct 2025 16:14:50 +0100 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 v3 17/29] arm_mpam: Extend reset logic to allow devices to be reset any time To: James Morse , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org Cc: D Scott Phillips OS , carl@os.amperecomputing.com, lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com, David Hildenbrand , Dave Martin , Koba Ko , Shanker Donthineni , fenghuay@nvidia.com, baisheng.gao@unisoc.com, Jonathan Cameron , Rob Herring , Rohit Mathew , Rafael Wysocki , Len Brown , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , Will Deacon , Greg Kroah-Hartman , Danilo Krummrich , Jeremy Linton , Gavin Shan References: <20251017185645.26604-1-james.morse@arm.com> <20251017185645.26604-18-james.morse@arm.com> From: Ben Horgan Content-Language: en-US In-Reply-To: <20251017185645.26604-18-james.morse@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi James, On 10/17/25 19:56, James Morse wrote: > cpuhp callbacks aren't the only time the MSC configuration may need to > be reset. Resctrl has an API call to reset a class. > If an MPAM error interrupt arrives it indicates the driver has > misprogrammed an MSC. The safest thing to do is reset all the MSCs > and disable MPAM. > > Add a helper to reset RIS via their class. Call this from mpam_disable(), > which can be scheduled from the error interrupt handler. > > Signed-off-by: James Morse > Reviewed-by: Jonathan Cameron > Reviewed-by: Ben Horgan > Tested-by: Fenghua Yu > --- > Changes since v2: > * Reduced the scop of arguments in mpam_reset_component_locked(). > > Changes since v1: > * more complete use of _srcu helpers. > * Use guard macro for srcu. > * Dropped a might_sleep() - something else will bark. > --- > drivers/resctrl/mpam_devices.c | 58 ++++++++++++++++++++++++++++++++-- > 1 file changed, 55 insertions(+), 3 deletions(-) > > diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c > index ec089593acad..545482e112b7 100644 > --- a/drivers/resctrl/mpam_devices.c > +++ b/drivers/resctrl/mpam_devices.c > @@ -802,15 +802,13 @@ static void mpam_reset_ris_partid(struct mpam_msc_ris *ris, u16 partid) > > /* > * Called via smp_call_on_cpu() to prevent migration, while still being > - * pre-emptible. > + * pre-emptible. Caller must hold mpam_srcu. > */ > static int mpam_reset_ris(void *arg) > { > u16 partid, partid_max; > struct mpam_msc_ris *ris = arg; > > - WARN_ON_ONCE(!srcu_read_lock_held((&mpam_srcu))); > - > if (ris->in_reset_state) > return 0; > > @@ -1328,8 +1326,56 @@ static void mpam_enable_once(void) > mpam_partid_max + 1, mpam_pmg_max + 1); > } > > +static void mpam_reset_component_locked(struct mpam_component *comp) > +{ > + Nit: Extra blank line. > + struct mpam_vmsc *vmsc; > + > + lockdep_assert_cpus_held(); > + > + guard(srcu)(&mpam_srcu); > + list_for_each_entry_srcu(vmsc, &comp->vmsc, comp_list, > + srcu_read_lock_held(&mpam_srcu)) { > + struct mpam_msc *msc = vmsc->msc; > + struct mpam_msc_ris *ris; > + > + list_for_each_entry_srcu(ris, &vmsc->ris, vmsc_list, > + srcu_read_lock_held(&mpam_srcu)) { > + if (!ris->in_reset_state) > + mpam_touch_msc(msc, mpam_reset_ris, ris); > + ris->in_reset_state = true; > + } > + } > +} > + -- Thanks, Ben