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Notes
General
The causes of these vulnerabilities are rooted in CPU hardware design choices intended to optimize performance.
https://lwn.net/Articles/755419/
https://pdfs.semanticscholar.org/2209/42809262c17b6631c0f6536c91aaf7756857.pdf
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The FPU state may contain sensitive information such as cryptographic keys. As an example, the Intel AES instruction set (AES-NI) uses FPU registers to store round keys. It is only possible to exploit when the underlying operating system or hypervisor uses lazy FPU switching.
https://blog.cyberus-technology.de/posts/2018-06-06-intel-lazyfp-vulnerability.html