Subject: Re: [PATCH V4 05/13] hyperv: Add Write/Read MSR registers via ghcb page

From: Greg KH <[email-masked]>
Date: Fri, 27 Aug 2021 19:41:46 +0200

On Fri, Aug 27, 2021 at 01:21:03PM -0400, Tianyu Lan wrote:
> From: Tianyu Lan <[email-masked]>
> 
> Hyperv provides GHCB protocol to write Synthetic Interrupt
> Controller MSR registers in Isolation VM with AMD SEV SNP
> and these registers are emulated by hypervisor directly.
> Hyperv requires to write SINTx MSR registers twice. First
> writes MSR via GHCB page to communicate with hypervisor
> and then writes wrmsr instruction to talk with paravisor
> which runs in VMPL0. Guest OS ID MSR also needs to be set
> via GHCB page.
> 
> Signed-off-by: Tianyu Lan <[email-masked]>
> ---
> Change since v1:
>          * Introduce sev_es_ghcb_hv_call_simple() and share code
>            between SEV and Hyper-V code.
> Change since v3:
>          * Pass old_msg_type to hv_signal_eom() as parameter.
> 	 * Use HV_REGISTER_* marcro instead of HV_X64_MSR_*
> 	 * Add hv_isolation_type_snp() weak function.
> 	 * Add maros to set syinc register in ARM code.
> ---
>  arch/arm64/include/asm/mshyperv.h |  23 ++++++
>  arch/x86/hyperv/hv_init.c         |  36 ++--------
>  arch/x86/hyperv/ivm.c             | 112 ++++++++++++++++++++++++++++++
>  arch/x86/include/asm/mshyperv.h   |  80 ++++++++++++++++++++-
>  arch/x86/include/asm/sev.h        |   3 +
>  arch/x86/kernel/sev-shared.c      |  63 ++++++++++-------
>  drivers/hv/hv.c                   | 112 ++++++++++++++++++++----------
>  drivers/hv/hv_common.c            |   6 ++
>  include/asm-generic/mshyperv.h    |   4 +-
>  9 files changed, 345 insertions(+), 94 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h
> index 20070a847304..ced83297e009 100644
> --- a/arch/arm64/include/asm/mshyperv.h
> +++ b/arch/arm64/include/asm/mshyperv.h
> @@ -41,6 +41,29 @@ static inline u64 hv_get_register(unsigned int reg)
>  	return hv_get_vpreg(reg);
>  }
>  
> +#define hv_get_simp(val)	{ val = hv_get_register(HV_REGISTER_SIMP); }
> +#define hv_set_simp(val)	hv_set_register(HV_REGISTER_SIMP, val)
> +
> +#define hv_get_siefp(val)	{ val = hv_get_register(HV_REGISTER_SIEFP); }
> +#define hv_set_siefp(val)	hv_set_register(HV_REGISTER_SIEFP, val)
> +
> +#define hv_get_synint_state(int_num, val) {			\
> +	val = hv_get_register(HV_REGISTER_SINT0 + int_num);	\
> +	}
> +
> +#define hv_set_synint_state(int_num, val)			\
> +	hv_set_register(HV_REGISTER_SINT0 + int_num, val)
> +
> +#define hv_get_synic_state(val) {			\
> +	val = hv_get_register(HV_REGISTER_SCONTROL);	\
> +	}
> +
> +#define hv_set_synic_state(val)			\
> +	hv_set_register(HV_REGISTER_SCONTROL, val)
> +
> +#define hv_signal_eom(old_msg_type)		 \
> +	hv_set_register(HV_REGISTER_EOM, 0)

Please just use real inline functions and not #defines if you really
need it.

thanks,

greg k-h