On 10/22/14 10:25, Dong, Eric wrote:
> Laszlo,
>
> The OsIndications will be processed before boot the first boot
> option, detail process is in PlatformBdsEnterFrontPage function.
> (IntelFrameworkModulePkg/Universal/BdsDxe/FrontPage.c)
> BdsEntry() -> PlatformBdsPolicyBehavior() ->
> PlatformBdsEnterFrontPage().
That's interesting!
I've been aware that PlatformBdsEnterFrontPage() processes
"OsIndications". However, at least in the OVMF build,
PlatformBdsEnterFrontPage() is never reached automatically, under the
circumstances I described. Here's the call tree again (this time more
densely, without the comments):
BdsEntry() [Intel BDS]
BdsFormalizeEfiGlobalVariable() [Intel BDS]
PlatformBdsPolicyBehavior() [OVMF]
BdsBootDeviceSelect() [Intel BDS]
PlatformBdsEnterFrontPage() [Intel BDS] -- never reached
Apparently, it is the responsibility of PlatformBdsPolicyBehavior() to
call PlatformBdsEnterFrontPage()!
At the moment, OVMF's PlatformBdsPolicyBehavior() only calls
PlatformBdsEnterFrontPage() if the user presses a key on the TianoCore
splash screen.
I'm experimenting with this.
Thanks a lot,
Laszlo
>
> //
> // goto FrontPage directly when EFI_OS_INDICATIONS_BOOT_TO_FW_UI is set
> //
> OsIndication = 0;
> DataSize = sizeof(UINT64);
> Status = gRT->GetVariable (
> L"OsIndications",
> &gEfiGlobalVariableGuid,
> NULL,
> &DataSize,
> &OsIndication
> );
>
> //
> // goto FrontPage directly when EFI_OS_INDICATIONS_BOOT_TO_FW_UI is set.
> Skip HotkeyBoot
> //
> if (!EFI_ERROR(Status) && ((OsIndication &
> EFI_OS_INDICATIONS_BOOT_TO_FW_UI) != 0)) {
> ......
>
> Thanks,
> Eric
>
> -----Original Message-----
> From: Laszlo Ersek [mailto:ler...@redhat.com]
> Sent: Tuesday, October 21, 2014 7:14 PM
> To: edk2-devel list
> Subject: [edk2] BDS: should BootOrder or OsIndications take priority?
>
> Section "7.5.4 Exchanging information between the OS and Firmware" in the
> UEFI spec seems to imply that if bit 0 is set in both OsIndicationsSupported
> and OsIndications, then at next boot the firmware should stop at the firmware
> UI. It appears that this OS-side request is independent of, and prevails
> over, any BootOrder and Boot#### settings.
>
> Is the above interpretation correct? And if so, does the Intel BDS driver
> diverge from it?
>
> Namely,
>
> BdsEntry()
> [IntelFrameworkModulePkg/Universal/BdsDxe/BdsEntry.c]
> BdsFormalizeEfiGlobalVariable()
> // verifies the size, contents, and
> // attributes of "OsIndications",
> // but doesn't act upon it
> PlatformBdsPolicyBehavior() [...]
> // might rework Boot#### and
> // BootOrder
> BdsBootDeviceSelect()
> [IntelFrameworkModulePkg/Universal/BdsDxe/BdsEntry.c]
> // invokes the firmware UI only if:
> // - no active boot option, or
> // - all active boot options
> // failed to boot, or
> // - an active boot option
> // succeded, and returned to the
> // firmware.
> PlatformBdsEnterFrontPage()
> [IntelFrameworkModulePkg/Universal/BdsDxe/FrontPage.c]
> // looks at OsIndications
>
> That is, the driver seems to enforce a "formal correctness" of
> "OsIndications" early enough, but the code that would *act* upon it is never
> reached if there is at least one active and successful boot option that boots
> an OS.
>
> In other words, the Intel BDS code seems to favor BootOrder and Boot####
> above OsIndications. Is that a divergence from the UEFI spec?
>
> Thanks,
> Laszlo
>
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