[PATCH v6 1/6] arm64: smccc: Add support for SMCCCv1.2 extended input/output registers

[Sudeep Holla]

Hi Michael,

On Wed, May 05, 2021 at 03:28:56PM +0000, Michael Kelley wrote:
> From: Sudeep Holla <sudeep.holla at arm.com> Sent: Wednesday, May 5, 2021 2:39 AM
> > 
> > SMCCC v1.2 allows x8-x17 to be used as parameter registers and x4—x17
> > to be used as result registers in SMC64/HVC64. Arm Firmware Framework
> > for Armv8-A specification makes use of x0-x7 as parameter and result
> > registers. There are other users like Hyper-V who intend to use beyond
> > x0-x7 as well.
> > 
> > Current SMCCC interface in the kernel just use x0-x7 as parameter and
> > x0-x3 as result registers as required by SMCCCv1.0. Let us add new
> > interface to support this extended set of input/output registers namely
> > x0-x17 as both parameter and result registers.
> > 

[...]

> I've tested the new arm_smccc_1_2_hvc() function in the context
> of Linux guests making hypercalls on Hyper-V for ARM64, and it
> works as intended.   But note that my test case only uses X0 thru X7.
> 
> Tested-by: Michael Kelley <mikelley at microsoft.com>
> Reviewed-by: Michael Kelley <mikelley at microsoft.com>

Thanks!

-- 
Regards,
Sudeep