On Fri, Apr 28, 2023 at 02:50:04PM +0000, Michael Brown wrote: > On 28/04/2023 14:38, Gerd Hoffmann wrote: > > I suspect the windows boot loader does something fishy here, but I can't > > proof it, I have not yet pinned down the exact location where interrupts > > get enabled while running at IPL=TPL_HIGH_LEVEL (which is what I suspect > > is happening, but of course this is not the only possible theory how > > that ASSERT got triggered). > > > > Not fully sure how to best continue debugging this, I don't think gdb > > can set an watchpoint on eflags.if ... > > In the absence of any better ideas, I'd be tempted to run QEMU via TCG > instead of KVM, and hack the STI instruction definition to check the > location in guest memory where gEfiCurrentTpl gets stored in your test > build. (It's brute force debugging, but it should find the culprit.)
Not so easy as tcg generates code for cli+sti, so there isn't a function I could add logging hacks to. > From a quick check of the implementation, I'm pretty sure this will be the > case. However, the logic is already (necessarily) pretty complex and so I > am not 100% sure of this. The reasoning behind the logic in > NestedInterruptTplLib relies on certain axioms and invariants (e.g. that > there are a finite number of distinct TPLs, and that there are certain > places within the code that further interrupts provably cannot occur), and > so it gets very difficult to reason about when one of those invariants is > violated, as it seems to be in this situation. > > If it seems to work, It seems to work, and the warning is printed exactly once during boot. > with a warning message, and to return with InterruptedTPL unmodified. But > I'd prefer to understand how this invariant violation arises in the first > place. Root cause not found yet, but all debugging so far didn't found any problems in edk2/ovmf, so my theory still is that windows does something fishy here. take care, Gerd -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#103880): https://edk2.groups.io/g/devel/message/103880 Mute This Topic: https://groups.io/mt/98554842/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
