From:   "Michael Kelley (LINUX)" <mikelley@microsoft.com>
To:     Saurabh Sengar <ssengar@linux.microsoft.com>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "mingo@redhat.com" <mingo@redhat.com>,
        "bp@alien8.de" <bp@alien8.de>,
        "dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
        "x86@kernel.org" <x86@kernel.org>, "hpa@zytor.com" <hpa@zytor.com>,
        KY Srinivasan <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        "wei.liu@kernel.org" <wei.liu@kernel.org>,
        Dexuan Cui <decui@microsoft.com>,
        "arnd@arndb.de" <arnd@arndb.de>,
        Tianyu Lan <Tianyu.Lan@microsoft.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>
Subject: RE: [PATCH v3 4/5] x86/hyperv: VTL support for Hyper-V
Thread-Topic: [PATCH v3 4/5] x86/hyperv: VTL support for Hyper-V
Thread-Index: AQHZWxNEDmrxXEJK60WJ//1R5me3Jq8D+O6g
Date:   Mon, 20 Mar 2023 18:16:37 +0000
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References: <1679306618-31484-1-git-send-email-ssengar@linux.microsoft.com>
 <1679306618-31484-5-git-send-email-ssengar@linux.microsoft.com>
In-Reply-To: <1679306618-31484-5-git-send-email-ssengar@linux.microsoft.com>
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From: Saurabh Sengar <ssengar@linux.microsoft.com> Sent: Monday, March 20, =
2023 3:04 AM
>=20
=20
[snip]

> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyp=
erv.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>
>=20
> +#define HV_VTL_NORMAL 0x0
> +#define HV_VTL_SECURE 0x1
> +#define HV_VTL_MGMT   0x2
> +
>  union hv_ghcb;
>=20
>  DECLARE_STATIC_KEY_FALSE(isolation_type_snp);
> @@ -272,6 +276,12 @@ static inline int hv_set_mem_host_visibility(unsigne=
d long
> addr, int numpages,
>  #endif /* CONFIG_HYPERV */
>=20
>=20
> +#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 bee=
n
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>
>=20
>  #endif
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyper=
v.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)
>=20
>  	/* 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