Michal Orzel c035151902 x86: Clarify that only 5 hypercall parameters are supported ...

The x86 hypercall ABI really used to have 6-argument hypercalls.  V4V, the
downstream predecessor to Argo did take 6th args.

However, the 6th arg being %ebp in the 32bit ABI makes it unusable in
practice, because that's the frame pointer in builds with frame pointers
enabled.  Therefore Argo was altered to being a 5-arg hypercall when it was
upstreamed.

c/s 2f531c122e ("x86: limit number of hypercall parameters to 5") removed
the ability for hypercalls to take 6 arguments.

Update the documentation to match reality.

Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>

2023-10-10 10:03:49 +01:00

..

x86

x86: Clarify that only 5 hypercall parameters are supported

2023-10-10 10:03:49 +01:00

index.rst

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2019-12-06 18:45:43 +00:00