Robert Mustacchi

And... having it written down. Like I've gone back to some of these and been like, Oh, good job. Pass me. I'm glad it's here. Cause I know I was just going to say, I forgot. Yeah.

And... having it written down. Like I've gone back to some of these and been like, Oh, good job. Pass me. I'm glad it's here. Cause I know I was just going to say, I forgot. Yeah.

write a block comment when and you can go make an artifact better by just explaining how it works yeah i think as i've been flipping back through my notebook here for things that are um things that aren't meeting notes a lot of it really is uh you know just a whole bunch of things around like you know if there are problems it's like starting with questions i'm trying to answer and go figure out what those are um you know even on uh

write a block comment when and you can go make an artifact better by just explaining how it works yeah i think as i've been flipping back through my notebook here for things that are um things that aren't meeting notes a lot of it really is uh you know just a whole bunch of things around like you know if there are problems it's like starting with questions i'm trying to answer and go figure out what those are um you know even on uh

thursdays or fridays lr dim hunt is the same thing yeah just like what are some of the things what are some of the observations what's different um you know and i find that writing stuff down is a helpful focusing thing and that those for me i learned a lot about i mean everyone everyone learns in different ways so it's not going to be the same for everyone but for me uh physically writing in mostly illegible cursive that looks good from a distance is uh

thursdays or fridays lr dim hunt is the same thing yeah just like what are some of the things what are some of the observations what's different um you know and i find that writing stuff down is a helpful focusing thing and that those for me i learned a lot about i mean everyone everyone learns in different ways so it's not going to be the same for everyone but for me uh physically writing in mostly illegible cursive that looks good from a distance is uh

Indeed.

Indeed.

Yeah, actually, I think my memory is that you or Alex probably saw it first. Probably with Spectre and Meltdown. This is being like the... It's put back in Linux in a way that starts leaking and everyone's kind of denying it until they stop denying it. I think is the...

Yeah, actually, I think my memory is that you or Alex probably saw it first. Probably with Spectre and Meltdown. This is being like the... It's put back in Linux in a way that starts leaking and everyone's kind of denying it until they stop denying it. I think is the...

More than 10. Yeah.

More than 10. Yeah.

Yeah, there was a lot of different parts to it. And so it was a combination of Alex and also John Levin, who was very helpful to have while working on that. And obviously, lots of conversations with others. But yeah, we were able to kind of split up that work into a bunch of different pieces. I think I dealt with per CPU page tables, which was an exciting thing in its own right.

Yeah, there was a lot of different parts to it. And so it was a combination of Alex and also John Levin, who was very helpful to have while working on that. And obviously, lots of conversations with others. But yeah, we were able to kind of split up that work into a bunch of different pieces. I think I dealt with per CPU page tables, which was an exciting thing in its own right.

I think Alex dealt with a lot of the trampoline assembly. But we also kind of settled on a somewhat unique solution, I feel like, that hadn't really been done by others with the per CPU page tables.

I think Alex dealt with a lot of the trampoline assembly. But we also kind of settled on a somewhat unique solution, I feel like, that hadn't really been done by others with the per CPU page tables.

Yeah. So yeah, that's a great question. So, um, On x86, ARM, and a bunch of other common RISC-V CPUs, when you use the MMU, you have page tables that describe virtual to physical mappings. So every process has its own address space and maps to generally disjoint physical memory, and those page tables describe where they exist. and different attributes.

Yeah. So yeah, that's a great question. So, um, On x86, ARM, and a bunch of other common RISC-V CPUs, when you use the MMU, you have page tables that describe virtual to physical mappings. So every process has its own address space and maps to generally disjoint physical memory, and those page tables describe where they exist. and different attributes.

So some of those attributes say this page can be read, this page can be written, this page can be executed. One of the attributes are basically permissions in terms of what the privileges are required to read, write, or execute that page. So you can really think of this as that there's a whole bunch of memory that people sometimes call kernel memory and then memory for processes.

So some of those attributes say this page can be read, this page can be written, this page can be executed. One of the attributes are basically permissions in terms of what the privileges are required to read, write, or execute that page. So you can really think of this as that there's a whole bunch of memory that people sometimes call kernel memory and then memory for processes.