Linux-HyperV Archive on lore.kernel.org
 help / color / Atom feed
From: Wei Hu <weh@microsoft.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>
Subject: RE: [bug report] video: hyperv: hyperv_fb: Use physical memory for fb on HyperV Gen 1 VMs.
Date: Wed, 5 Feb 2020 11:33:03 +0000
Message-ID: <SG2P153MB038005492C6FE395B6523A8EBB020@SG2P153MB0380.APCP153.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <20200205080733.GU11068@kadam>



> -----Original Message-----
> > Thanks for reporting this. Would you let me know how I can reproduce
> > this warning or Error message? The build on my side runs fine without such
> message.
> 
> Hm...  Sorry, I never publish this Smatch check.  I should do that.
> Anyway HCH explains the rules a bit in this email:
> 
> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkml.or
> g%2Flkml%2F2019%2F6%2F17%2F155&amp;data=02%7C01%7Cweh%40micro
> soft.com%7Cff5687dc7bb648623d3708d7aa127a4b%7C72f988bf86f141af91a
> b2d7cd011db47%7C1%7C0%7C637164868648450097&amp;sdata=0%2B8Jwe
> 1A%2FtOW0LqF8t2hqymWuzZjVtUxBIKgMyOQdFc%3D&amp;reserved=0
> 

I see. This is virtual frame buffer device on Hyper-V. It would not get address from 
vmap or ioremap. On the other hand, if dma_alloc_coherent() returns address without
page backing, this driver will blow even without calling virt_to_phys. 

Dma_alloc_coherent() is the recommended interface to allocate large contiguous
physical memory, in which case this call is doing so. I think you can ignore this 
in your check.

Thanks,
Wei

      reply index

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-05  5:43 Dan Carpenter
2020-02-05  7:21 ` Wei Hu
2020-02-05  8:07   ` Dan Carpenter
2020-02-05 11:33     ` Wei Hu [this message]

Reply instructions:

You may reply publically 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=SG2P153MB038005492C6FE395B6523A8EBB020@SG2P153MB0380.APCP153.PROD.OUTLOOK.COM \
    --to=weh@microsoft.com \
    --cc=dan.carpenter@oracle.com \
    --cc=linux-hyperv@vger.kernel.org \
    /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

Linux-HyperV Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-hyperv/0 linux-hyperv/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-hyperv linux-hyperv/ https://lore.kernel.org/linux-hyperv \
		linux-hyperv@vger.kernel.org
	public-inbox-index linux-hyperv

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-hyperv


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git