Messages in this thread | | | Date | Mon, 20 Mar 2023 17:54:11 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v5 25/34] x86/fred: disallow the swapgs instruction when FRED is enabled |
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On Mon, Mar 06, 2023 at 06:39:37PM -0800, Xin Li wrote: > From: "H. Peter Anvin (Intel)" <hpa@zytor.com> > > The FRED architecture establishes the full supervisor/user through: > 1) FRED event delivery swaps the value of the GS base address and > that of the IA32_KERNEL_GS_BASE MSR. > 2) ERETU swaps the value of the GS base address and that of the > IA32_KERNEL_GS_BASE MSR. > Thus, the swapgs instruction is disallowed when FRED is enabled, > otherwise it cauess #UD. ^^^ --- new word :-)
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