linux-kernel - Re: [PATCH v4] x86/Hyper-V: Support for free page reporting

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:   Mon, 22 Mar 2021 11:16:21 +0000
From:   Wei Liu <wei.liu@...nel.org>
To:     Michael Kelley <mikelley@...rosoft.com>
Cc:     Sunil Muthuswamy <sunilmut@...rosoft.com>,
        Matheus Castello <matheus@...tello.eng.br>,
        "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        Wei Liu <liuwe@...rosoft.com>,
        Tianyu Lan <Tianyu.Lan@...rosoft.com>,
        Wei Liu <wei.liu@...nel.org>, vkuznets <vkuznets@...hat.com>,
        KY Srinivasan <kys@...rosoft.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4] x86/Hyper-V: Support for free page reporting

On Fri, Mar 19, 2021 at 09:30:50PM +0000, Michael Kelley wrote:
> From: Sunil Muthuswamy <sunilmut@...rosoft.com>  Sent: Friday, March 19, 2021 2:21 PM
> > 
> > > What's the strategy for this flag in the unlikely event that the hypercall fails?
> > > It doesn't seem right to have hv_query_ext_cap() fail, but leave the
> > > static flag set to true.  Just move that line down to after the status check
> > > has succeeded?
> > 
> > That call should not fail in any normal circumstances. The current idea was to
> > avoid repeating the same call on persistent failure. 
> 
> OK, I can see that as a valid strategy.  And the assumption is that a failed
> hypercall would leave hv_extended_cap unmodified and hence all zeros.
> 
> I'm OK with this approach if you want to keep it.  But perhaps add a short
> comment about the intent so it doesn't look like a bug. :-)
> 

Sunil, if you can send an updated version of your patch by either
providing a comment or moving the code around, I can queue it up for
hyperv-next.

I think adding a comment is perhaps the easier thing to do.

Wei.