linux-kernel - RE: [PATCH 1/2] x86/hyperv: Move hv_do_rep

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Message-ID: <MWHPR21MB1593FA3F2A4FEC5CEFA2BCDAD7489@MWHPR21MB1593.namprd21.prod.outlook.com>
Date:   Tue, 20 Apr 2021 21:25:16 +0000
From:   Michael Kelley <mikelley@...rosoft.com>
To:     Joseph Salisbury <Joseph.Salisbury@...rosoft.com>,
        KY Srinivasan <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        "wei.liu@...nel.org" <wei.liu@...nel.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "bp@...en8.de" <bp@...en8.de>, "hpa@...or.com" <hpa@...or.com>
CC:     "x86@...nel.org" <x86@...nel.org>,
        "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 1/2] x86/hyperv: Move hv_do_rep_hypercall to asm-generic

From: Joseph Salisbury <joseph.salisbury@...ux.microsoft.com> Sent: Friday, April 16, 2021 5:43 PM
> 
> This patch makes no functional changes.  It simply moves hv_do_rep_hypercall()
> out of arch/x86/include/asm/mshyperv.h and into asm-generic/mshyperv.h
> 
> hv_do_rep_hypercall() is architecture independent, so it makes sense that it
> should be in the architecture independent mshyperv.h, not in the x86-specific
> mshyperv.h.
> 
> This is done in preperation for a follow up patch which creates a consistent
> pattern for checking Hyper-V hypercall status.
> 
> Signed-off-by: Joseph Salisbury <joseph.salisbury@...rosoft.com>
> ---
>  arch/x86/include/asm/mshyperv.h | 32 --------------------------------
>  include/asm-generic/mshyperv.h  | 31 +++++++++++++++++++++++++++++++
>  2 files changed, 31 insertions(+), 32 deletions(-)
> 
> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
> index ccf60a809a17..bfc98b490f07 100644
> --- a/arch/x86/include/asm/mshyperv.h
> +++ b/arch/x86/include/asm/mshyperv.h
> @@ -189,38 +189,6 @@ static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64
> input2)
>  	return hv_status;
>  }
> 
> -/*
> - * Rep hypercalls. Callers of this functions are supposed to ensure that
> - * rep_count and varhead_size comply with Hyper-V hypercall definition.
> - */
> -static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, u16 varhead_size,
> -				      void *input, void *output)
> -{
> -	u64 control = code;
> -	u64 status;
> -	u16 rep_comp;
> -
> -	control |= (u64)varhead_size << HV_HYPERCALL_VARHEAD_OFFSET;
> -	control |= (u64)rep_count << HV_HYPERCALL_REP_COMP_OFFSET;
> -
> -	do {
> -		status = hv_do_hypercall(control, input, output);
> -		if ((status & HV_HYPERCALL_RESULT_MASK) != HV_STATUS_SUCCESS)
> -			return status;
> -
> -		/* Bits 32-43 of status have 'Reps completed' data. */
> -		rep_comp = (status & HV_HYPERCALL_REP_COMP_MASK) >>
> -			HV_HYPERCALL_REP_COMP_OFFSET;
> -
> -		control &= ~HV_HYPERCALL_REP_START_MASK;
> -		control |= (u64)rep_comp << HV_HYPERCALL_REP_START_OFFSET;
> -
> -		touch_nmi_watchdog();
> -	} while (rep_comp < rep_count);
> -
> -	return status;
> -}
> -
>  extern struct hv_vp_assist_page **hv_vp_assist_page;
> 
>  static inline struct hv_vp_assist_page *hv_get_vp_assist_page(unsigned int cpu)
> diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
> index dff58a3db5d5..a5246a6ea02d 100644
> --- a/include/asm-generic/mshyperv.h
> +++ b/include/asm-generic/mshyperv.h
> @@ -41,6 +41,37 @@ extern struct ms_hyperv_info ms_hyperv;
>  extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
>  extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
> 
> +/*
> + * Rep hypercalls. Callers of this functions are supposed to ensure that
> + * rep_count and varhead_size comply with Hyper-V hypercall definition.
> + */
> +static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, u16 varhead_size,
> +				      void *input, void *output)
> +{
> +	u64 control = code;
> +	u64 status;
> +	u16 rep_comp;
> +
> +	control |= (u64)varhead_size << HV_HYPERCALL_VARHEAD_OFFSET;
> +	control |= (u64)rep_count << HV_HYPERCALL_REP_COMP_OFFSET;
> +
> +	do {
> +		status = hv_do_hypercall(control, input, output);
> +		if ((status & HV_HYPERCALL_RESULT_MASK) != HV_STATUS_SUCCESS)
> +			return status;
> +
> +		/* Bits 32-43 of status have 'Reps completed' data. */
> +		rep_comp = (status & HV_HYPERCALL_REP_COMP_MASK) >>
> +			HV_HYPERCALL_REP_COMP_OFFSET;
> +
> +		control &= ~HV_HYPERCALL_REP_START_MASK;
> +		control |= (u64)rep_comp << HV_HYPERCALL_REP_START_OFFSET;
> +
> +		touch_nmi_watchdog();
> +	} while (rep_comp < rep_count);
> +
> +	return status;
> +}
> 
>  /* Generate the guest OS identifier as described in the Hyper-V TLFS */
>  static inline  __u64 generate_guest_id(__u64 d_info1, __u64 kernel_version,
> --
> 2.17.1

Reviewed-by: Michael Kelley <mikelley@...rosoft.com>