From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 1A799372661 for ; Wed, 1 Apr 2026 11:39:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775043593; cv=none; b=dUtuRGwaaI86UdHUQTAtRR71Cogvu0+H5kGN6k6Mz2X51svHU3VBrAsZrmtlmYAUMoSZJU62tJpG6ZpDDHyUy2UgFGK9DROkpVVBdIPE0I279aOYk/ZkwymZa0qPmBUnDdHK1aatzy5qKbf/IkgAvfpls6T/8hLLERAKMgxxxKk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775043593; c=relaxed/simple; bh=brLi2CxkT8OsknOe2gRnXgDDN6nDEXe2PCEZt8AxjjQ=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=aWIrQ1ynuV0tCv/WwDkHXyQizyEQhmuc5FhBhe6oczFQMAB7GAJsq3G3aB1lbL0yfLH96EDBC9lLA3EuEKiVeWo1YLWPSyrTMJmPEEcoVUPfu0P0AvOFS4JmcAdHAtfl1oZBjeq4yjDY2OM9ddgktH5iE5DJGsUS5sJCLDA9O/E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=BKDXy8gS; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BKDXy8gS" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1775043591; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=mqezalPl4i3JBcgLVBe3bFLBNdF5OgFM/6xHTa3bquo=; b=BKDXy8gSfPExMkyrSGqd6BX15T0FlhTTZ2dkILZFDJOIwzZxglHe8R/RRCWAyoBBbfKaMk Jb58k1iF1iQm+HvbBHVfX39ZdOQD7j1cIWgH++0kg4fIGVL+IM0E2xL2yUPMIVNdtxBdpE z0sXpEuuVAaaOObhf2cHJgOmOLhmJbE= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-202-qe4Ff5YzMWiw4qyQPLAQqg-1; Wed, 01 Apr 2026 07:39:47 -0400 X-MC-Unique: qe4Ff5YzMWiw4qyQPLAQqg-1 X-Mimecast-MFC-AGG-ID: qe4Ff5YzMWiw4qyQPLAQqg_1775043586 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0B930195607D; Wed, 1 Apr 2026 11:39:46 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.44.22.6]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 17205180058B; Wed, 1 Apr 2026 11:39:45 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id BAB5321E6A28; Wed, 01 Apr 2026 13:39:42 +0200 (CEST) From: Markus Armbruster To: Alireza Sanaee Cc: , , , , , , , , , , , , , Subject: Re: [PATCH 9/9] hw/cxl: Add QMP status query for dynamic-capacity extent release In-Reply-To: <20260331155044.0000603d.alireza.sanaee@huawei.com> (Alireza Sanaee's message of "Tue, 31 Mar 2026 15:50:44 +0100") References: <20260325184259.366-1-alireza.sanaee@huawei.com> <20260325184259.366-10-alireza.sanaee@huawei.com> <87mrzuei5f.fsf@pond.sub.org> <20260327151811.00005564.alireza.sanaee@huawei.com> <87zf3s1ohc.fsf@pond.sub.org> <20260331155044.0000603d.alireza.sanaee@huawei.com> Date: Wed, 01 Apr 2026 13:39:42 +0200 Message-ID: <87tstu29kx.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Mimecast-MFC-PROC-ID: fvLztn0JellFa5fpgwvyRvb7NtR7AZZBQYAbburlAR4_1775043586 X-Mimecast-Originator: redhat.com Content-Type: text/plain Alireza Sanaee writes: > On Sat, 28 Mar 2026 07:01:51 +0100 > Markus Armbruster wrote: > > +CC Ira > > Hi Markus, > > Please look inline. I believe Ira might be able to help and we can see what he thinks. > >> Alireza Sanaee writes: >> >> > On Thu, 26 Mar 2026 16:15:40 +0100 >> > Markus Armbruster wrote: >> > >> > Hi Markus, >> > >> > This commit adds a test command to check whether an extent (a piece of memory region) has been released or not by the guest. >> > The process of removal is highly asynchronous, that's why I needed to add a new command to check it. >> > >> > I would be happy to drop this patch, as this is extra. >> >> So your motivation for adding the command is "just" testing. Correct? > > I wrote tests to make sure extents were released, and I used this QMP command to check. As long as this is the only known use case, we want # @unstable: This command is meant for debugging. in the QAPI schema. > Now there is background about extents where DCD was developed in Linux by @Ira, CCed [1]. > > In the DCD extent tracking section of the CXL spec, I see some commands > related to getting the extent list, maybe Ira can comment here. To be fair, knowing if an extent > was released or not is a useful information in general from orchestrator perspective. > > [1] https://patchew.org/linux/20250413-dcd-type2-upstream-v9-0-1d4911a0b365@intel.com/ If we believe there are other uses, but we're unsure the command actually serves them: # @unstable: This command is experimental. >> Can you think of other uses? >> >> In particular, would a management application need this query to monitor >> removal? > > I think management will get a signal on the removal given the schema in Ira's Linux kernel > patchset. I do not think this is implemented in QEMU at least (I might be missing something). I'm getting a feeling of "this is underbaked" :) But that's for the CXL maintainers to judge. >> The description of feature @unstable may need to be adjusted for the >> answers we work out here. > > Absolutely. > >> >> > >> > Thanks, >> > Ali >> >>