Messages in this thread | | | Date | Tue, 20 Oct 2020 17:48:12 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH v2 3/5] x86/boot/compressed/64: Check SEV encryption in 64-bit boot-path |
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On Tue, Oct 20, 2020 at 10:12:59AM -0400, Arvind Sankar wrote: > On Tue, Oct 20, 2020 at 02:18:54PM +0200, Joerg Roedel wrote: > Why use r10-r12 rather than the caller-save registers? Even for the head > code where you need to perserve the cr3 value you can just return it in > rax?
It can surely be optimized, but it makes the code less robust. This function is only called from assembly so the standard x86-64 calling conventions might not be followed strictly. I think its better to make as few assumptions as possible about the calling code to avoid regressions. Changes to the head code are not necessarily tested with SEV/SEV-ES guests by developers.
Regards,
Joerg
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