From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AF7013563C3 for ; Thu, 18 Dec 2025 15:48:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766072921; cv=none; b=db93e8k3DUWdL6wFIR57CAl1/DUP5niOTY3Ja6A7SCDsc7dnzFO7N+0YFgTUAKwzxrJjDsa0B7cAzEGrzWgPFmPVDmy6qGazRRUZBPWr0IDmOUj3UkT/zajOKZaXNGtNAxBxHvWDZH7jLxCSaIoGtNSKzrmO6KYB9sGk0qtQeTQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766072921; c=relaxed/simple; bh=JU885sk3XOjxrp64rmTKezw/3tZvXcSP8+o1tHf9rdQ=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=JfImAwhndWz6u1ERdL053XYsG/2okWYbZlBizXPIWwSKH/uiKl8GwQcpe7YndMSMcolusol0z4OzV4CgJy34Qm3i3B1nM7HQ1+FC6v5ETLjpjUMV4ASrgeiK5DPhAdNpBujYU7wr1suY83ihPY//M1VbyloQiHqOCEZo04fQKyA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.224.150]) by frasgout.his.huawei.com (SkyGuard) with ESMTPS id 4dXFS356h0zJ467G; Thu, 18 Dec 2025 23:48:03 +0800 (CST) Received: from dubpeml100005.china.huawei.com (unknown [7.214.146.113]) by mail.maildlp.com (Postfix) with ESMTPS id DFB084056B; Thu, 18 Dec 2025 23:48:34 +0800 (CST) Received: from localhost (10.203.177.15) by dubpeml100005.china.huawei.com (7.214.146.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Thu, 18 Dec 2025 15:48:34 +0000 Date: Thu, 18 Dec 2025 15:48:32 +0000 From: Jonathan Cameron To: Markus Armbruster CC: Davidlohr Bueso , , , , , , , , Subject: Re: [PATCH 3/5] hw/cxl: Allow BI by default in Window restrictions Message-ID: <20251218154832.00000159@huawei.com> In-Reply-To: <87wm2ki1wm.fsf@pond.sub.org> References: <20251103195209.1319917-1-dave@stgolabs.net> <20251103195209.1319917-4-dave@stgolabs.net> <87wm2ki1wm.fsf@pond.sub.org> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml100009.china.huawei.com (7.191.174.83) To dubpeml100005.china.huawei.com (7.214.146.113) On Thu, 18 Dec 2025 10:18:17 +0100 Markus Armbruster wrote: > Davidlohr Bueso writes: > > > Update the CFMW restrictions to also permit Back-Invalidate > > flows by default, which is aligned with the no-restrictions > > policy. > > > > While at it, document the 'restrictions=' option. > > I'd split the patch. Up to you. Hi Markus, As you note below the interface hasn't been in any release anyway and is part of the long backlog I'm carrying and slowly getting upstream. Bringing this in from the start with that restrictions control should be fine. However, backwards compatibility does need addressing as this changes the default for things we do create today (with no restrictions). In this particular case, I don't think we care because there are no BI capable devices before this series - so there can't be anything using this feature for the host memory range it describes. As such, the only result is the ACPI table says we have an extra flag set which no one will care about. Will need to update the ACPI table tests though. I'll check. Migration of CXL topologies is horribly broken currently anyway so that's not a problem here. Given current usecases are strictly software stack verification fixing that isn't a priority (yet). Jonathan > > > Tested-by: Dongjoo Seo > > Signed-off-by: Davidlohr Bueso > > --- > > hw/cxl/cxl-host.c | 2 +- > > qapi/machine.json | 3 ++- > > qemu-options.hx | 4 +++- > > 3 files changed, 6 insertions(+), 3 deletions(-) > > > > diff --git a/hw/cxl/cxl-host.c b/hw/cxl/cxl-host.c > > index e420b25176a6..ed0c76a31980 100644 > > --- a/hw/cxl/cxl-host.c > > +++ b/hw/cxl/cxl-host.c > > @@ -64,7 +64,7 @@ static void cxl_fixed_memory_window_config(CXLFixedMemoryWindowOptions *object, > > if (object->has_restrictions) { > > fw->restrictions = object->restrictions; > > } else { > > - fw->restrictions = 0xf; /* No restrictions */ > > + fw->restrictions = 0x2f; /* No restrictions */ > > } > > > > fw->targets = g_malloc0_n(fw->num_targets, sizeof(*fw->targets)); > > diff --git a/qapi/machine.json b/qapi/machine.json > > index 225690d2986a..85e31432b038 100644 > > --- a/qapi/machine.json > > +++ b/qapi/machine.json > > @@ -555,7 +555,8 @@ > > # BIT(2) - Volatile > > # BIT(3) - Persistent > > # BIT(4) - Fixed Device Config > > -# Default is 0xF > > +# BIT(5) - BI > > +# Default is 0x2F > > # > > # @targets: Target root bridge IDs from -device ...,id= for each > > # root bridge. > > This changes the default of @restrictions. No problem since > @restrictions has not been in any release. If it was, we'd have to > consider backward compatibility. > > [...] > >