On 10/09/17 16:17, 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. > > Cc: Star Zeng <[email protected]> > Cc: Eric Dong <[email protected]> > Cc: Jiewen Yao <[email protected]> > Cc: Michael Kinney <[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; >
If this patch is entirely identical to the previous version (v3), then you should have please picked up the review tags from Jordan and myself, the ones that you got for v3: http://mid.mail-archive.com/150696711831.2454.16712170525103415248@jljusten-skl [email protected]">http://mid.mail-archive.com/[email protected] This way we can quickly filter out already reviewed patches, and avoid re-reviewing when there are no changes. Your cover letter v4 0/6 also does not summarize the changes relative to v3; in the future please don't forget about that. Thanks Laszlo _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
