From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2EAD61EEA31 for ; Fri, 28 Nov 2025 07:36:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764315372; cv=none; b=PhccAjNSR5ZowBy7ZMHR0wZ98t2cJHnuHLP4l6w7BqXE8Cm9GGO87oIHtf06R4uutWPPWO9Dd7Z5seO6rZX0hsZHHop7CBARVIP17Kg70qIaDXVu0sTaTgp2Tds61zb2mFUg9I+sGeb4OqESoi8o83WAWM15W3xzN6Dk5ajQlQc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764315372; c=relaxed/simple; bh=8dndaidv7PWdI9f8/GeBMTDI2VguxBhw3M/fNnSgSBI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Xgczk5yVl6KtRjVLk2kc00ZTMNn213t2BRNX8OwjQb/rpJa/zf7K/QrhlZxcKglEAPUjMeLJMHqtReRAKoW6+29NN9mo68JF2SEvzIQGC1UA5HQ/hYhVgGYz1etfnmB4g1DL7QGepYg1A+52ntLE2KXGIEy4Gf430VF46b3Il3A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nrrHHsHU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nrrHHsHU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 599B7C4CEF1; Fri, 28 Nov 2025 07:36:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764315371; bh=8dndaidv7PWdI9f8/GeBMTDI2VguxBhw3M/fNnSgSBI=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=nrrHHsHUrLlLfaq4SklPUnzUaCWikqrMZGyRmcI0edgfE39prJtGrl6Q1rPCOhD/H eYJP8uOcHPDXDRpXx1l5haNcDfsXMl3Q1KxqV5Vw0W3wsTHxepowC3OJTL1nDr9YoO gIa/oANTVa8HEG8QKdyr2XiJlAuYnoPjuV74BuKh4gi+0DvA2ShwaJoHiogCsc0mZf /tNQfRuopsB36bwi/HSSSYfCxUZ8BCG7XmbktEkX5RvvMA4Er2jhiNAYSC0p3L1XpY Au2Hphs0H8ru0T50gjxuzWMiEQPy9qeC5UAzvPiaOo2UGfwssaZZYHgDolcl+bELtF My28HZWFK3vTA== Message-ID: <3cc7d401-c77c-4ac8-abb8-c264fbd9aaf0@kernel.org> Date: Fri, 28 Nov 2025 08:36:06 +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 v1 0/2] powerpc/pseries/cmm: two smaller fixes To: "Ritesh Harjani (IBM)" , linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, Andrew Morton , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy References: <20251021100606.148294-1-david@redhat.com> <557b5500-412a-4d26-8c4b-147c9a00d5fd@kernel.org> <87zf86n3vq.ritesh.list@gmail.com> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: <87zf86n3vq.ritesh.list@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 11/28/25 06:05, Ritesh Harjani (IBM) wrote: > "David Hildenbrand (Red Hat)" writes: > >> On 10/21/25 12:06, David Hildenbrand wrote: >>> Two smaller fixes identified while doing a bigger rework. >>> >>> Compile-tested only as I don't have an easy way to test right now. >>> >>> I would prefer for these patches to go through the MM tree as I will >>> be sending out a bigger version soon that is based on this series -- >>> I split of the fixes from the other stuff. >>> >> >> Ping, >> >> I tried to get CMM running again (using the simulation mode I introduced >> a while back), but so far my attempts to get a reasonable powernv VM >> booted in QEMU failed :( >> >> (e.g., Fedora qcow2 images use xfs, but the open powernv loader is based >> on a 5.10 kernel without some mystical XFS feature ...) >> > Hi Ritesh, > Sorry, I missed seeing this earlier. > > Do you have the link to simulation mode which you are referring above > please? So far I didn't find the support of this beyond Linux LPAR > (pseries), but maybe I missed it. When I did a rework of the CMM balloon in 2019, I needed a way to test it. So I added commit b1713975c31ae20ecc40fd00191ee3fa51445d4a Author: David Hildenbrand Date: Thu Oct 31 15:29:31 2019 +0100 powerpc/pseries/cmm: Simulation mode Let's allow to test the implementation without needing HW support. When "simulate=1" is specified when loading the module, we bypass all HW checks and HW calls. The sysfs file "simulate_loan_target_kb" can be used to simulate HW requests. The simualtion mode can be activated using: modprobe cmm debug=1 simulate=1 And the requested loan target can be changed using: echo X > /sys/devices/system/cmm/cmm0/simulate_loan_target_kb I allows for bypassing the absence of FW_FEATURE_CMO. Back in the days I was able to test it with a pseries (or was it powernv?) machine we had here at RH. So far my attempts failed to test it in a similar fashion in QEMU. -- Cheers David