Muli Ben-Yehuda's journal

I think I’ll take a break from Calgary today as it’s such a beautiful day outside. I verify that all DMA allocations (dma_alloc_coherent, dma_map_single, dma_map_sg) actually have valid TCE entries, and still either the SAS controller or the USB OHCI controller kill the machine on boot. Either I have a bug in both the allocation and verification or these devices are DMA’ing without the drivers having gone through the DMA API first. We’ll see.

Calgary is now running with translation enabled in the lab on our x366 servers. We’ve been working on this for a while now, bug after bug, but yesterday I had a fit of inspiration, fixed the last one, and now it boots all the way to userspace, with SAS, NICs and USB all DMA’ing fine(!!!). The last bug was particularly stupid – we were writing a 64 bit quantity into the 64 bit TCE Table Address register – with a 32 bit call (writel instead of writeq). Argh!

I’ll detail the more interesting bugs we had for All Code Sucks, eventually. At the moment Calgary is running with static mappings (the identity translation – TCE ‘x’ maps physical address ‘x’, and all physical addresses have corresponding TCEs), and the next step is dynamic mappings. Which I’ve worked on until 2 AM last night. It doesn’t work yet. But it will. Real Soon Now 🙂

Date: Wed, 15 Feb 2006 17:14:27 -0600 (CST)
From: papers@linuxsymposium.org
To: mulix@mulix.org
Subject: Proposal Utilizing IOMMUs for Virtualization in Linux and Xen

Your paper proposal Utilizing IOMMUs for Virtualization in Linux and Xen
has been accepted by the 2006 Linux Symposium Committee.

I have been feeling elated and depressed in short cycles lately, depending on where things I have no control over are standing at any given point in time. Trying to break out of the circle is doable. A good first step would be to get off my ass and go to the gym.

I spent the weekend hacking and thought we achieved the next major milestone on the HW bringup. Turned out that my code had the world’s stupidest bug and we’re still not quite there yet (I was initializing the same PHB 8 times instead of initializing the 8 PHBs…). So depressing!

My todo list grows daily. I wish I could become a reclusive kung-fu fighting monk for a few months.

My new wallpaper, from our visit to West Point last year:

The runner up:

So much to do and so little time!

AMD’s IOMMU spec is now available.

Two OLS papers submitted: “Utilizing IOMMUs for Virtualization in
Linux and Xen” and “Smarter Linux Support for Smart IO
Devices”. Hopefully at least one will manage to squeak in by the
program committee 🙂

[muli] Calgary said "Daddy" today for the first time
[muli] of course it pronounced it 0xfda00000, but that's fine too

I signed up for the gym today. On the one hand, I’m a firm believer that shame is a great motivator, which leads me to suspect that if I commit to writing about my gym escapades (and the associated diet, etc, etc), I’ll actually get stuff done. On the other hand, once I get in the groove of things, I tend to go to the gym a lot, and wouldn’t want they gym experience to overwhelm the other stuff I write about. So, how to strike a balance?

Answer: the muligymdream community, where you can read my uncensored and most likely highly boring gym escapades, should you wish to. This journal will retain its usual non-content.

P.S. if anyone reading this is in the middle of a diet / exercise regime, and wishes to write about it on muligymdream, let me know. United, we stand. Alone, we roll along…

I haven’t written one of these in a while, let’s see if I still remember how.

Spent last week at Austin, Texas. Two days at the Austin Xen summit, and then the rest of the week with the LTC-Xen crew. Mostly it went very well, and the summit was much more interesting than I expected it to be, but we also hit a few snags on the HW side of things. Actually, “snags” is putting it mildly, “bloody painful razor-sharp blades” is a tad more accurate.

This week has been spent trying to catch up after I landed on Sunday evening. My sleep cycle is all screwed up, and my TODO list is growing at a very alarming rate. I better stop blogging soon and start shrinking it 🙂

We are working on an OLS paper proposal on Linux and Xen exploitation of upcoming IOMMUs, which I will post here after we finalize it. I guess that means I’ll attempt to get to OLS again this year, even though I didn’t intend to after last year.

No word yet from Usenix on the two papers we submitted. I am told the acceptance rate this year will be 10-15%. Ouch.

What else? spent most of the week battling with HW, and the battle is not nearly done yet. We are making headway, but paying through the nose for every inch of ground we take. Have devised a circling maneuver to be executed once we take the fortified position immediately to the front. There’s no point in trying to flank it, it must be taken.

I have been reviewing many papers lately, for research and patent purposes. You can see an up-to-date list of interesting papers at citeulike.

Canceled my talk at OSDC and will probably not attend. Can’t afford the time right now. Also, declined to give the drivers talk in the Technion. Can’t afford the time for that either.

Plans for next week: resume the battle and make headway on the bringup; study for upcoming exams; finalize OLS paper proposal and start writing it; slink back to the gym, and don’t look back.

Slides from the Xen Winter Summit at Austin are starting to show up. Our Xen/IOMMU Integration should be there soon.