Hyeonggon Yoo
Posts
469Following
90Followers
94- Intern @ NVIDIA Korea (Security System Software) (2024.06 ~)
- Ex-Intern @ Panmneisa (CXL emulation stuff) (~2023.12)
- Undergraduate majoring CSE (estimated graduation: Feb. 2025)
- Working as reviewer at Linux Slab subsystem
- Born in August 6, 2000
Opinions are my own.
My interests are:
Memory Management,
Computer Architecture,
Circuit Design,
Virtualization
Hyeonggon Yoo
hyeyoo
Edited 1 year ago
This winter I'm going to do a research project (for the first time in my life!) with other students, at Purdue University (Indiana).
2 months is bit short for a project, so we need to find a very small question that no one has answered.
It seems I've found a question suitable for our need in the compiler area, but I need to consult with the professor to verify if it's a valid question.
2 months is bit short for a project, so we need to find a very small question that no one has answered.
It seems I've found a question suitable for our need in the compiler area, but I need to consult with the professor to verify if it's a valid question.
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Hyeonggon Yoo
hyeyoo
After 2 months of learning related stuffs I finally feel like I'm ready to dive into CXL device emulation code.
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Hyeonggon Yoo
hyeyoo
Edited 1 year ago
a foolish mistake: can't open my phone's card wallet because of the strap I bought yesterday...
Should've realized that I can't have both :(
Should've realized that I can't have both :(
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Hyeonggon Yoo
hyeyoo
Edited 1 year ago
There are two ways to access device registers in PCIe:
1) As an extended capability in PCIe extended configuration space, (Designated) Vendor-Specific Extended Capabilities can be used to access vendor-specific registers. As more than one vendor produces CXL devices, DVSEC is used instead of VSEC.
2) BARs can be used to map device resources (registers or memory) into system memory address space.
Errrr.. btw many registers are there in the CXL spec :/
Notably:
- (DVSEC) "PCIe DVSEC for CXL Device" is used to identify CXL-capable PCIe endpoints
- (DVSEC) "Register Locator DVSEC" is used to locate CXL memory-mapped registers
- (Memory-Mapped) "CXL 2.0 Component Registers" is used to configure CXL Components (Host Bridge, Root Port, Upstream/Downstream Port, Device)
- (Memory-Mapped) "CXL Device Register Interface" is used to access CXL device registers and issue commands to a CXL device
Configuration space of Every CXL 2.0 component can be accessed via the standard PCIe method, except Host Bridges. Component Registers of CXL Host Bridges are located by ACPI CEDT table, which also contains CFMWS (CXL Fixed-Memory-Window Structure).
1) As an extended capability in PCIe extended configuration space, (Designated) Vendor-Specific Extended Capabilities can be used to access vendor-specific registers. As more than one vendor produces CXL devices, DVSEC is used instead of VSEC.
2) BARs can be used to map device resources (registers or memory) into system memory address space.
Errrr.. btw many registers are there in the CXL spec :/
Notably:
- (DVSEC) "PCIe DVSEC for CXL Device" is used to identify CXL-capable PCIe endpoints
- (DVSEC) "Register Locator DVSEC" is used to locate CXL memory-mapped registers
- (Memory-Mapped) "CXL 2.0 Component Registers" is used to configure CXL Components (Host Bridge, Root Port, Upstream/Downstream Port, Device)
- (Memory-Mapped) "CXL Device Register Interface" is used to access CXL device registers and issue commands to a CXL device
Configuration space of Every CXL 2.0 component can be accessed via the standard PCIe method, except Host Bridges. Component Registers of CXL Host Bridges are located by ACPI CEDT table, which also contains CFMWS (CXL Fixed-Memory-Window Structure).
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Hyeonggon Yoo
repeated
repeated
Kees Cook 
kees@fosstodon.org
Here's how to enable the kernel Memory Tagging Extension (#MTE) on the Pixel 8:
adb shell setprop arm64.memtag.bootctl memtag,memtag-kernel
I'm so happy there's real-world hardware finally available to provide mitigations against linear buffer overflows and many types of use-after-free flaws.
More details here:
https://outflux.net/blog/archives/2023/10/26/enable-mte-on-pixel-8/
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@cwayne I don't want to lose it :(
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@vbabka @cwayne
Soju is Korea's traditional distilled spirit.
It's clear, neutral spirit usually distilled from grains. The taste is sometimes bitter and sometimes sweet ;)
Most of time koreans drink Soju or beer when drinking socially. And it's also used to measure one's drinking limit (like, "how many bottles of Soju can you drink?")
Soju is Korea's traditional distilled spirit.
It's clear, neutral spirit usually distilled from grains. The taste is sometimes bitter and sometimes sweet ;)
Most of time koreans drink Soju or beer when drinking socially. And it's also used to measure one's drinking limit (like, "how many bottles of Soju can you drink?")
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@cwayne
Whiskey's bit expensive to drink enough (TM) :P
I'd rather drink Soju sir (about $1~$3 per bottle)
Whiskey's bit expensive to drink enough (TM) :P
I'd rather drink Soju sir (about $1~$3 per bottle)
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@monsieuricon
hmm they are still same "whiskeys" to me ;)
probably I need to drink more to learn the difference in taste
hmm they are still same "whiskeys" to me ;)
probably I need to drink more to learn the difference in taste
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@cwayne
I'm almost immune to a hangover unless I drink like crazy 😁
I'm almost immune to a hangover unless I drink like crazy 😁
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@monsieuricon haha I'm new to whiskey; isn't bourbon allowed to be in the same line-up as Scotch whiskey?
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Hyeonggon Yoo
hyeyoo
I have a thing (wanna do at some point in my life) for designing processors, memory modules and neuromorphic processors
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