linux-kernel - Re: [PATCH v2 0/4] Add support for updated vmware hypercall instruction

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Date:   Tue, 27 Aug 2019 10:33:21 +0200
From:   Thomas Hellström (VMware) 
        <thomas_os@...pmail.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     linux-kernel@...r.kernel.org, pv-drivers@...are.com,
        linux-graphics-maintainer@...are.com,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org
Subject: Re: [PATCH v2 0/4] Add support for updated vmware hypercall
 instruction

Thomas,

On 8/23/19 10:13 AM, Thomas Hellström (VMware) wrote:
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Borislav Petkov <bp@...en8.de>
> Cc: "H. Peter Anvin" <hpa@...or.com>
> Cc: <x86@...nel.org>
>
> VMware has started using "vmcall" / "vmmcall" instead of an inl instruction
> for the "backdoor" interface. This series detects support for those
> instructions.
> Outside of the platform code we use the "ALTERNATIVES" self-patching
> mechanism similarly to how this is done with KVM.
> Unfortunately we need two new x86 CPU feature flags for this, since we need
> the default instruction to be "inl". IIRC the vmmouse driver is used by
> other virtualization solutions than VMware, and those might break if
> they encounter any of the other instructions.
>
> v2:
> - Address various style review comments
> - Use mnemonics instead of bytecode in the ALTERNATIVE_2 macros
> - Use vmcall / vmmcall also for the High-Bandwidth port calls
> - Change the %edx argument to what vmcall / vmmcall expect (flags instead of
>    port number). The port number is added in the default ALTERNATIVE_2 path.
> - Ack to merge the vmmouse patch from Dmitry.
> - Drop license update for now. Will get back with a freestanding patch.
Are you OK taking the above series through the x86 tree? In addition to 
the ack from Dmitry to do this for the vmmouse patch, there's also an 
ack from Dave to do the same for vmwgfx.

Thanks,
Thomas