On Sun, Jan 16, 2022 at 09:53:06PM +0000, Haiyang Zhang wrote: > > > > -----Original Message----- > > From: Michael Kelley (LINUX) <mikel...@microsoft.com> > > Sent: Sunday, January 16, 2022 2:19 PM > > To: KY Srinivasan <k...@microsoft.com>; Haiyang Zhang > > <haiya...@microsoft.com>; Stephen > > Hemminger <sthem...@microsoft.com>; wei....@kernel.org; Wei Hu > > <w...@microsoft.com>; Dexuan > > Cui <de...@microsoft.com>; drawat.fl...@gmail.com; hhei <h...@redhat.com>; > > linux- > > ker...@vger.kernel.org; linux-hyp...@vger.kernel.org; > > linux-fb...@vger.kernel.org; dri- > > de...@lists.freedesktop.org > > Cc: Michael Kelley (LINUX) <mikel...@microsoft.com> > > Subject: [PATCH 1/1] video: hyperv_fb: Fix validation of screen resolution > > > > In the WIN10 version of the Synthetic Video protocol with Hyper-V, > > Hyper-V reports a list of supported resolutions as part of the protocol > > negotiation. The driver calculates the maximum width and height from > > the list of resolutions, and uses those maximums to validate any screen > > resolution specified in the video= option on the kernel boot line. > > > > This method of validation is incorrect. For example, the list of > > supported resolutions could contain 1600x1200 and 1920x1080, both of > > which fit in an 8 Mbyte frame buffer. But calculating the max width > > and height yields 1920 and 1200, and 1920x1200 resolution does not fit > > in an 8 Mbyte frame buffer. Unfortunately, this resolution is accepted, > > causing a kernel fault when the driver accesses memory outside the > > frame buffer. > > > > Instead, validate the specified screen resolution by calculating > > its size, and comparing against the frame buffer size. Delete the > > code for calculating the max width and height from the list of > > resolutions, since these max values have no use. Also add the > > frame buffer size to the info message to aid in understanding why > > a resolution might be rejected. > > > > Fixes: 67e7cdb4829d ("video: hyperv: hyperv_fb: Obtain screen resolution > > from Hyper-V > > host") > > Signed-off-by: Michael Kelley <mikel...@microsoft.com> [...] > > Reviewed-by: Haiyang Zhang <haiya...@microsoft.com> >
Applied to hyperv-fixes. Thanks.