RE: [PATCH v3 4/5] x86/hyperv: VTL support for Hyper-V

[Michael Kelley (LINUX)]

From: Saurabh Sengar <ssengar@xxxxxxxxxxxxxxxxxxx> Sent: Monday, March 20, 2023 3:04 AM
> 
 
[snip]

> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
> index 35b16b177035..4af218e70395 100644
> --- a/arch/x86/include/asm/mshyperv.h
> +++ b/arch/x86/include/asm/mshyperv.h
> @@ -11,6 +11,10 @@
>  #include <asm/paravirt.h>
>  #include <asm/mshyperv.h>
> 
> +#define HV_VTL_NORMAL 0x0
> +#define HV_VTL_SECURE 0x1
> +#define HV_VTL_MGMT   0x2
> +
>  union hv_ghcb;
> 
>  DECLARE_STATIC_KEY_FALSE(isolation_type_snp);
> @@ -272,6 +276,12 @@ static inline int hv_set_mem_host_visibility(unsigned long
> addr, int numpages,
>  #endif /* CONFIG_HYPERV */
> 
> 
> +#ifdef CONFIG_HYPERV_VTL_MODE

Hmmm.  CONFIG_HYPERV_VTL_MODE isn't defined until Patch 5 of this series.
I guess this works because of #ifdef behavior with non-existent values, but
it is a little bit weird to be referencing a CONFIG_ option that hasn't been
defined yet.

> +void __init hv_vtl_init_platform(void);
> +#else
> +static inline void __init hv_vtl_init_platform(void) {}
> +#endif
> +
>  #include <asm-generic/mshyperv.h>
> 
>  #endif
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index 61363ce0b335..0dd385cdc332 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -520,6 +520,7 @@ static void __init ms_hyperv_init_platform(void)
> 
>  	/* Register Hyper-V specific clocksource */
>  	hv_init_clocksource();
> +	hv_vtl_init_platform();
>  #endif
>  	/*
>  	 * TSC should be marked as unstable only after Hyper-V
> --
> 2.34.1