Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <20191107205914.10611-1-deepa.kernel@gmail.com>
 <1672a5861c82c2e3c0c54b5311fd413a8eee5e64.camel@infradead.org>
 <8D8B600C3EC1B64FAD4503F0B66C61F23BB95B@SHSMSX103.ccr.corp.intel.com>
 <addba4e401c3bf23b86cf8dff97256282895e29f.camel@infradead.org>
 <8D8B600C3EC1B64FAD4503F0B66C61F23BBA24@SHSMSX103.ccr.corp.intel.com>
 <CABeXuvoiX639HchLbgTHLiXPh=Yr2dJHUp2Yqc6pNJ3As1OJ8A@mail.gmail.com> <CABeXuvqMpXbSNasET4-u16Hrj710fe-V706tsFZhOTJoir8Xjw@mail.gmail.com>
In-Reply-To: <CABeXuvqMpXbSNasET4-u16Hrj710fe-V706tsFZhOTJoir8Xjw@mail.gmail.com>
From:   Deepa Dinamani <deepa.kernel@gmail.com>
Date:   Sun, 10 Nov 2019 12:36:49 -0800
Message-ID: <CABeXuvrYzLoc7YGtmXDJqEovwyERbndN4cC6UaYAw5+qABRr8A@mail.gmail.com>
Subject: Re: [PATCH] intel-iommu: Turn off translations at shutdown
To:     "Zeng, Jason" <jason.zeng@intel.com>
Cc:     David Woodhouse <dwmw2@infradead.org>,
        "joro@8bytes.org" <joro@8bytes.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        "Tian, Kevin" <kevin.tian@intel.com>,
        Arnd Bergmann <arnd@arndb.de>, rminnich@google.com
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Sun, Nov 10, 2019 at 10:24 AM Deepa Dinamani <deepa.kernel@gmail.com> wrote:
>
> On Fri, Nov 8, 2019 at 2:48 PM Deepa Dinamani <deepa.kernel@gmail.com> wrote:
> >
> > > > > For VMM live update case, we should be able to detect and bypass
> > > > > the shutdown that Deepa introduced here, so keep IOMMU still operating?
> > > >
> > > > Is that a 'yes' to Deepa's "if someone wants to make it conditional, we
> > > > can do that" ?
> > >
> > > Yes, I think so. Thanks!
> >
> > Are these changes already part of the kernel like avoiding shutdown of
> > the passthrough devices? device_shutdown() doesn't seem to be doing
> > anything selectively as of now.
>
> I've posted the v2 without the conditional for now:
> https://lore.kernel.org/patchwork/patch/1151225/
>
> As a side topic, I'm trying to support https://www.linuxboot.org/. I
> have a couple of more such cleanups coming. The VMM live updates and
> linuxboot seem to have contradicting requirements and they both use
> kexec. So kexec_in_progress doesn't seem like a sufficient indicator
> to distinguish between the two. Do you already have an idea on how to
> distiguish between them? Does a separate sys_reboot() command
> parameter sound ok? Or, we could use the flags in the sys_kexec_load()
> depending on how the live update feature is implemented.

Also, the AMD driver disables iommu at shutdown already. So the live
update feature is already broken on AMD.

-Deepa