From: Michael Kelley <mikelley@microsoft.com>
To: Michael Kelley <mikelley@microsoft.com>,
Wei Hu <weh@microsoft.com>,
"rdunlap@infradead.org" <rdunlap@infradead.org>,
"shc_work@mail.ru" <shc_work@mail.ru>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"lee.jones@linaro.org" <lee.jones@linaro.org>,
"alexandre.belloni@bootlin.com" <alexandre.belloni@bootlin.com>,
"baijiaju1990@gmail.com" <baijiaju1990@gmail.com>,
"info@metux.net" <info@metux.net>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
"linux-fbdev@vger.kernel.org" <linux-fbdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"sashal@kernel.org" <sashal@kernel.org>,
Stephen Hemminger <sthemmin@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
KY Srinivasan <kys@microsoft.com>,
Dexuan Cui <decui@microsoft.com>
Subject: RE: [PATHC v6] video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver
Date: Fri, 20 Sep 2019 17:26:34 +0000 [thread overview]
Message-ID: <DM5PR21MB01375E8543451D4550D622CDD7880@DM5PR21MB0137.namprd21.prod.outlook.com> (raw)
In-Reply-To: <DM5PR21MB0137DA408FE59E8C1171CFFCD78E0@DM5PR21MB0137.namprd21.prod.outlook.com>
From: Michael Kelley <mikelley@microsoft.com> Sent: Wednesday, September 18, 2019 2:48 PM
> >
> > Without deferred IO support, hyperv_fb driver informs the host to refresh
> > the entire guest frame buffer at fixed rate, e.g. at 20Hz, no matter there
> > is screen update or not. This patch supports deferred IO for screens in
> > graphics mode and also enables the frame buffer on-demand refresh. The
> > highest refresh rate is still set at 20Hz.
> >
> > Currently Hyper-V only takes a physical address from guest as the starting
> > address of frame buffer. This implies the guest must allocate contiguous
> > physical memory for frame buffer. In addition, Hyper-V Gen 2 VMs only
> > accept address from MMIO region as frame buffer address. Due to these
> > limitations on Hyper-V host, we keep a shadow copy of frame buffer
> > in the guest. This means one more copy of the dirty rectangle inside
> > guest when doing the on-demand refresh. This can be optimized in the
> > future with help from host. For now the host performance gain from deferred
> > IO outweighs the shadow copy impact in the guest.
> >
> > Signed-off-by: Wei Hu <weh@microsoft.com>
Sasha -- this patch and one other from Wei Hu for the Hyper-V frame buffer
driver should be ready. Both patches affect only the Hyper-V frame buffer
driver so can go through the Hyper-V tree. Can you pick these up? Thx.
Michael
next prev parent reply other threads:[~2019-09-20 17:26 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-18 6:03 [PATHC v6] video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver Wei Hu
2019-09-18 16:45 ` Dexuan Cui
2019-09-18 21:48 ` Michael Kelley
2019-09-20 17:26 ` Michael Kelley [this message]
2019-10-01 18:48 ` Sasha Levin
2019-10-02 8:09 ` Dexuan Cui
2019-10-02 12:40 ` Sasha Levin
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