Re: [PATCH v4 0/4] Add support for XMM fast hypercalls

[Siddharth Chandrasekaran <sidcha@amazon.de>]

On Wed, May 26, 2021 at 10:56:07AM +0200, Siddharth Chandrasekaran wrote:
> Hyper-V supports the use of XMM registers to perform fast hypercalls.
> This allows guests to take advantage of the improved performance of the
> fast hypercall interface even though a hypercall may require more than
> (the current maximum of) two general purpose registers.
> 
> The XMM fast hypercall interface uses an additional six XMM registers
> (XMM0 to XMM5) to allow the caller to pass an input parameter block of
> up to 112 bytes. Hyper-V can also return data back to the guest in the
> remaining XMM registers that are not used by the current hypercall.
> 
> Although the Hyper-v TLFS mentions that a guest cannot use this feature
> unless the hypervisor advertises support for it, some hypercalls which
> we plan on upstreaming in future uses them anyway. This patchset adds
> necessary infrastructure for handling input/output via XMM registers and
> patches kvm_hv_flush_tlb() to use xmm input arguments.

Hi Paolo,

Are you expecting more reviews on these patches? 

Thanks. 

~ Sid



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