Linux IOMMU Development
 help / color / mirror / Atom feed
From: Yong Wu via iommu <iommu@lists.linux-foundation.org>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: yf.wang@mediatek.com, yen-chang.chen@mediatek.com,
	Will Deacon <will@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
	xueqi.zhang@mediatek.com, mingyuan.ma@mediatek.com,
	devicetree@vger.kernel.org, chengci.xu@mediatek.com,
	libo.kang@mediatek.com, Rob Herring <robh+dt@kernel.org>,
	linux-mediatek@lists.infradead.org,
	Hsin-Yi Wang <hsinyi@chromium.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	linux-arm-kernel@lists.infradead.org, anan.sun@mediatek.com,
	srv_heupstream@mediatek.com, linux-kernel@vger.kernel.org,
	iommu@lists.linux-foundation.org,
	Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v4 08/35] iommu/mediatek: Use kmalloc for protect buffer
Date: Wed, 16 Feb 2022 13:54:59 +0800	[thread overview]
Message-ID: <d9637b40196873f392ac9cebfe369106a6f0eee7.camel@mediatek.com> (raw)
In-Reply-To: <ca47becf-adc9-f11e-5e59-03f203920344@collabora.com>

On Thu, 2022-01-27 at 12:08 +0100, AngeloGioacchino Del Regno wrote:
> Il 25/01/22 09:56, Yong Wu ha scritto:
> > No need zero for the protect buffer that is only accessed by the
> > IOMMU HW
> > translation fault happened.
> > 
> > Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> 
> I would rather keep this a devm_kzalloc instead... the cost is very
> minimal and
> this will be handy when new hardware will be introduced, as it may
> require a bigger
> buffer: in that case, "older" platforms will use only part of it and
> we may get
> garbage data at the end.

Currently this is to avoid zero 512 bytes for all the platforms.

Sorry, I don't understand why it is unnecessary when the new hardware
requires a bigger buffer. If the buffer becomes bigger, then clearing
it to 0 need more cost. then this patch is more helpful?

The content in this buffer is garbage, we won't care about or analyse
it.

> 
> Regards,
> Angelo

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply	other threads:[~2022-02-16  5:55 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-25  8:55 [PATCH v4 00/35] MT8195 IOMMU SUPPORT Yong Wu
2022-01-25  8:56 ` [PATCH v4 01/35] dt-bindings: mediatek: mt8195: Add binding for MM IOMMU Yong Wu
2022-01-25  8:56 ` [PATCH v4 02/35] dt-bindings: mediatek: mt8195: Add binding for infra IOMMU Yong Wu
2022-01-25  8:56 ` [PATCH v4 03/35] iommu/mediatek: Fix 2 HW sharing pgtable issue Yong Wu
2022-01-27 10:59   ` AngeloGioacchino Del Regno
2022-01-25  8:56 ` [PATCH v4 04/35] iommu/mediatek: Add list_del in mtk_iommu_remove Yong Wu
2022-01-25  8:56 ` [PATCH v4 05/35] iommu/mediatek: Remove clk_disable " Yong Wu
2022-01-25  8:56 ` [PATCH v4 06/35] iommu/mediatek: Add mutex for m4u_group and m4u_dom in data Yong Wu
2022-01-27 11:02   ` AngeloGioacchino Del Regno
2022-01-25  8:56 ` [PATCH v4 07/35] iommu/mediatek: Add mutex for data in the mtk_iommu_domain Yong Wu
2022-01-27 11:02   ` AngeloGioacchino Del Regno
2022-01-25  8:56 ` [PATCH v4 08/35] iommu/mediatek: Use kmalloc for protect buffer Yong Wu
2022-01-27 11:08   ` AngeloGioacchino Del Regno
2022-02-16  5:54     ` Yong Wu via iommu [this message]
2022-02-16  5:59       ` Tomasz Figa
2022-02-16  8:11         ` Yong Wu via iommu
2022-01-25  8:56 ` [PATCH v4 09/35] iommu/mediatek: Adapt sharing and non-sharing pgtable case Yong Wu
2022-01-25  8:56 ` [PATCH v4 10/35] iommu/mediatek: Add 12G~16G support for multi domains Yong Wu
2022-01-25  8:56 ` [PATCH v4 11/35] iommu/mediatek: Add a flag DCM_DISABLE Yong Wu
2022-01-25  8:56 ` [PATCH v4 12/35] iommu/mediatek: Add a flag NON_STD_AXI Yong Wu
2022-01-25  8:56 ` [PATCH v4 13/35] iommu/mediatek: Remove the granule in the tlb flush Yong Wu
2022-01-25  8:56 ` [PATCH v4 14/35] iommu/mediatek: Always enable output PA over 32bits in isr Yong Wu
2022-01-25  8:56 ` [PATCH v4 15/35] iommu/mediatek: Add SUB_COMMON_3BITS flag Yong Wu
2022-01-25  8:56 ` [PATCH v4 16/35] iommu/mediatek: Add IOMMU_TYPE flag Yong Wu
2022-01-25  8:56 ` [PATCH v4 17/35] iommu/mediatek: Contain MM IOMMU flow with the MM TYPE Yong Wu
2022-01-25  8:56 ` [PATCH v4 18/35] iommu/mediatek: Adjust device link when it is sub-common Yong Wu
2022-01-25  8:56 ` [PATCH v4 19/35] iommu/mediatek: Allow IOMMU_DOMAIN_UNMANAGED for PCIe VFIO Yong Wu
2022-01-25  8:56 ` [PATCH v4 20/35] iommu/mediatek: Add a PM_CLK_AO flag for infra iommu Yong Wu
2022-01-25  8:56 ` [PATCH v4 21/35] iommu/mediatek: Add infra iommu support Yong Wu
2022-01-25  8:56 ` [PATCH v4 22/35] iommu/mediatek: Add PCIe support Yong Wu
2022-01-25  8:56 ` [PATCH v4 23/35] iommu/mediatek: Add mt8195 support Yong Wu
2022-01-25  8:56 ` [PATCH v4 24/35] iommu/mediatek: Only adjust code about register base Yong Wu
2022-01-25  8:56 ` [PATCH v4 25/35] iommu/mediatek: Just move code position in hw_init Yong Wu
2022-01-25  8:56 ` [PATCH v4 26/35] iommu/mediatek: Separate mtk_iommu_data for v1 and v2 Yong Wu
2022-01-25  8:56 ` [PATCH v4 27/35] iommu/mediatek: Remove mtk_iommu.h Yong Wu
2022-01-27 11:15   ` AngeloGioacchino Del Regno
2022-01-25  8:56 ` [PATCH v4 28/35] iommu/mediatek-v1: Just rename mtk_iommu to mtk_iommu_v1 Yong Wu
2022-01-25  8:56 ` [PATCH v4 29/35] iommu/mediatek: Add mtk_iommu_bank_data structure Yong Wu
2022-01-27 11:17   ` AngeloGioacchino Del Regno
2022-01-25  8:56 ` [PATCH v4 30/35] iommu/mediatek: Initialise bank HW for each a bank Yong Wu
2022-01-25  8:56 ` [PATCH v4 31/35] iommu/mediatek: Change the domid to iova_region_id Yong Wu
2022-01-25  8:56 ` [PATCH v4 32/35] iommu/mediatek: Get the proper bankid for multi banks Yong Wu
2022-01-27 11:21   ` AngeloGioacchino Del Regno
2022-01-25  8:56 ` [PATCH v4 33/35] iommu/mediatek: Initialise/Remove for multi bank dev Yong Wu
2022-01-25  8:56 ` [PATCH v4 34/35] iommu/mediatek: Backup/restore regsiters for multi banks Yong Wu
2022-01-27 11:24   ` AngeloGioacchino Del Regno
2022-01-25  8:56 ` [PATCH v4 35/35] iommu/mediatek: mt8195: Enable multi banks for infra iommu Yong Wu
2022-01-27 11:25   ` AngeloGioacchino Del Regno

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=d9637b40196873f392ac9cebfe369106a6f0eee7.camel@mediatek.com \
    --to=iommu@lists.linux-foundation.org \
    --cc=anan.sun@mediatek.com \
    --cc=angelogioacchino.delregno@collabora.com \
    --cc=chengci.xu@mediatek.com \
    --cc=devicetree@vger.kernel.org \
    --cc=hsinyi@chromium.org \
    --cc=krzysztof.kozlowski@canonical.com \
    --cc=libo.kang@mediatek.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mediatek@lists.infradead.org \
    --cc=matthias.bgg@gmail.com \
    --cc=mingyuan.ma@mediatek.com \
    --cc=robh+dt@kernel.org \
    --cc=robin.murphy@arm.com \
    --cc=srv_heupstream@mediatek.com \
    --cc=will@kernel.org \
    --cc=xueqi.zhang@mediatek.com \
    --cc=yen-chang.chen@mediatek.com \
    --cc=yf.wang@mediatek.com \
    --cc=yong.wu@mediatek.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox