Reviewed-by: Jordan Justen <[email protected]>
On 2017-09-27 18:03:53, Jian J Wang wrote: > QemuVideoDxe driver will link VBE SHIM into page 0. If NULL pointer > detection is enabled, this driver will fail to load. NULL pointer detection > bypassing code is added to prevent such problem during boot. > > Please note that Windows 7 will try to access VBE SHIM during boot if it's > installed, and then cause boot failure. This can be fixed by setting BIT7 > of PcdNullPointerDetectionPropertyMask to disable NULL pointer detection > after EndOfDxe. As far as we know, there's no other OSs has such issue. > > > According to Laszlo, remove the code disabling/enabling the NULL pointer > > detection but just ignore the installing if it's enabled > > Cc: Star Zeng <[email protected]> > Cc: Eric Dong <[email protected]> > Cc: Laszlo Ersek <[email protected]> > Cc: Jiewen Yao <[email protected]> > Cc: Michael Kinney <[email protected]> > Cc: Jordan Justen <[email protected]> > Cc: Ayellet Wolman <[email protected]> > Suggested-by: Ayellet Wolman <[email protected]> > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Jian J Wang <[email protected]> > --- > OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf | 1 + > OvmfPkg/QemuVideoDxe/VbeShim.c | 14 ++++++++++++++ > 2 files changed, 15 insertions(+) > > diff --git a/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf > b/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf > index 577e07b0a8..ff68c99e96 100644 > --- a/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf > +++ b/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf > @@ -77,3 +77,4 @@ > [Pcd] > gOptionRomPkgTokenSpaceGuid.PcdDriverSupportedEfiVersion > gUefiOvmfPkgTokenSpaceGuid.PcdOvmfHostBridgePciDevId > + gEfiMdeModulePkgTokenSpaceGuid.PcdNullPointerDetectionPropertyMask > diff --git a/OvmfPkg/QemuVideoDxe/VbeShim.c b/OvmfPkg/QemuVideoDxe/VbeShim.c > index e45a08e887..8ba5522cde 100644 > --- a/OvmfPkg/QemuVideoDxe/VbeShim.c > +++ b/OvmfPkg/QemuVideoDxe/VbeShim.c > @@ -75,6 +75,20 @@ InstallVbeShim ( > UINTN Printed; > VBE_MODE_INFO *VbeModeInfo; > > + if ((PcdGet8 (PcdNullPointerDetectionPropertyMask) & (BIT0|BIT7)) == BIT0) > { > + DEBUG (( > + DEBUG_WARN, > + "%a: page 0 protected, not installing VBE shim\n", > + __FUNCTION__ > + )); > + DEBUG (( > + DEBUG_WARN, > + "%a: page 0 protection prevents Windows 7 from booting anyway\n", > + __FUNCTION__ > + )); > + return; > + } > + > Segment0 = 0x00000; > SegmentC = 0xC0000; > SegmentF = 0xF0000; > -- > 2.14.1.windows.1 > _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
