CIRCLE WITH A DOT

@ihatecompvir an 'open world' classic...

@zen literally...

what if i just muted the phrase microslop

@moses_izumi honestly im only really interested in the boot chain stuff, not so much the games. i dont actually have an xbox one

@moses_izumi to be clear psp means platform security processor in this context; the talk was about breaking the chain of trust in the xbox one bootloader

does everyone doing these projects just do it as a drive-by or something. quick in and out project, and if you finish early you can just leave

disappoint me why dont you. not that my expectations were high for a talk principally about the psp, and really hardware fault injection is only so interesting, but i feel like if you are going to do the whole attention grabbing thing of hacking the xbox one the least you can do is make your own graphs

really funny watching the xbox one psp talk and thinking Oh that graph looks like it was laid out by ai. and then by the end of the video in the q&a section he confirms yeah absolutely its ai generated

@domi @chfour though if you were to do it under svm and simply trap any device accesses that might work...

@domi @chfour i have no idea about this though ive never looked into it

@domi @chfour i do assume that would be harder just since windows likely assumes (otherwise rightly so) that any page it flushes will be valid targets for an isa or pci dma operation, and so probably doesnt tag such pages explicitly in a way that a cache only system could differentiate automatically

@domi @chfour if nothing else its worth it for access to the architectural 'machine segment,' which seems to have unprotected read-write access to not just msrs but also like. cache and various internal state variables and microcode and stuff maybe?

@LilaHexe @domi ive seen stuff like that before and i always wonder if theyve just never heard of ternary logic or something

@sudo200 honestly i learned everything i know about amd microcode out of two pdfs and five markdown files; im not sure its that far out of reach if youre interested in learning it

@sudo200 @chfour i think in many respects cisc machine code is simply ir, so the more symbolic and less literal it is the better chance you get at runtime to optimize it for the underlying silicon, which is really all compilers do

@sudo200 @chfour cpus have done predecode for decades now but i think with higher level source machine code and self synchronization that lets you get away with much more intelligent and of course much more parallel reordering, and in ideal cases the ability to do the entire decode step for an instruction page ahead of execution, whereupon you can simply copy them verbatim into the pipeline without actually decoding anything in realtime. the catch is it uses a whole lot of power and die space

@sudo200 @chfour generally speaking i believe in cisc design principles, so without a doubt variable length, lots of orthogonality, and a lot of compound instructions. but unlike x86 the instruction stream would be self synchronizing, which makes it much easier to decode instructions and fetch and sequence microoperations ahead of execution

@chfour yes itll be awesome

honestly i might try implementing this on zen 2 if i can find an appropriate instruction to override

'multiply sign extended bool bitwise-and constant with value and conditional branch on result' is an instruction i keep wishing i had