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That article links a commit [1] that contradicts this statement > AMD processors are not subject to the types of attacks that the kernel page table isolation f
by buryat 9y ago
That article links a commit [1] that contradicts this statement
> AMD processors are not subject to the types of attacks that the kernel
page table isolation feature protects against. The AMD microarchitecture
does not allow memory references, including speculative references, that
access higher privileged data when running in a lesser privileged mode
when that access would result in a page fault.
And Axios [2] that Zdnet quotes gave a comment from AMD:
> "To be clear, the security research team identified three variants targeting speculative execution. The threat and the response to the three variants differ by microprocessor company, and AMD is not susceptible to all three variants. Due to differences in AMD's architecture, we believe there is a near zero risk to AMD processors at this time. We expect the security research to be published later today and will provide further updates at that time."
And a comment from ARM:
> Please note that our Cortex-M processors, which are pervasive in low-power, connected IoT devices, are not impacted.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=694d99d40972f12e59a3696effee8a376b79d7c8 https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/...
[2] https://www.axios.com/how-the-giants-of-tech-are-dealing-with-a-massive-chip-vulnerability-2522206367.html https://www.axios.com/how-the-giants-of-tech-are-dealing-wit...
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- ethbro 9y agoMy read is that vulnerable processors generally have to: 1. Have out of order execution 2. Have aggressive speculative memory load / caching behavior 3. Be able to speculatively cache memory not owned by the current process (either kernel or otherwise) 4. Have deterministic ways of triggering a speculative load / read to the same memory location 2 is probably the saving grace in ARM / low power land, given they don't have the power budget to trade speculative loads for performance (in the event they're even out of order in the first place). Caveat: I'm drinking pretty strong Belgian beer while reading through these papers.
- Pyxl101 9y agoHow does that pertain to the vulnerabilities that involve eBPF? My understanding is that eBPF code executes within the kernel, and so would run at the same privilege level.
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