The SMC problem was solved in following manner:
- Every trace linked to another remembers when it was linked (a special timestamp value called traceLinkTimeStamp)
- When true SMC happens it incremements the traceLinkTimeStamp
- Jump to the linked trace won't be allowed if traceLinkTimeStamp in the link doesn't match traceLinkTimeStamp
So SMC effectively breaks all trace links and therefore I should not care for them anymore
5%-10% speedup on OS boot benchamarks observed
After a lot of thinking and browsing in the SVM arch forums I assume now that it shold be fine to enter to paged real mode under SVM guest.
The test case to consider:
(paged) real mode guest -> entering Pmode (not paged) -> disabling the Pmode back
Ths assumption still should be validated with real AMD hardware
Context: AMD's manual about CR0 intercept priority :
"Checks non-memory exceptions (CPL, illegal bit combinations, etc.) before the intercept"
The check for 'paged real mode' suposed to be illegal bit combination ...
The Windows version looks almost stable, but the GTK version fails in some cases.
That's why the classic wx debugger is still available if BX_DEBUGGER_GUI is set to 0.
- added function close_debug_dialog() to handle the simulation stop case in wx
- disable all the wx debugger related code if BX_DEBUGGER_GUI is set to 1
- added enhanced debugger specific init code similar to the code in sdl.cc
- include debugger related resources on Windows
- TODO: make the GTK / wxGTK case stable and remove the wx debugger
I observed ~5% emulation slowdown ... thinking about possible mitigations
this fixes TLB issue with SMAP and SMEP features.
these features introduce a new behavior when page can be inaccessible by System (CPL=0).
Current behavior is accessBits was not supporting it but legacy (from Bochs 2.3.6) was.
The wrong behavior can be observed if user access a user page and system access the same page later.
user access is fine and pass SMEP/SMA checks and stores the translation in TLB.
the system access will hit the TLB and nobody could detect that system cannot access that page.
