Re: [Xen-devel] [PATCH for-next v3 9/9] x86: introduce CONFIG_HYPERV and detection code

[Paul Durrant <pdurrant@xxxxxxxxx>]

On Mon, 21 Oct 2019 at 17:01, Wei Liu <wl@xxxxxxx> wrote:
>
> We use the same code structure as we did for Xen.
>
> As starters, detect Hyper-V in probe routine. More complex
> functionalities will be added later.
>
> Signed-off-by: Wei Liu <liuwe@xxxxxxxxxxxxx>

Reviewed-by: Paul Durrant <paul@xxxxxxx>

...with one suggestion...

> ---
> V3:
> 1. Remove some unused code
> 2. Rename structure
> 3. Also detect HV#1 signature
> ---
>  xen/arch/x86/Kconfig               |  9 +++++
>  xen/arch/x86/guest/Makefile        |  1 +
>  xen/arch/x86/guest/hyperv/Makefile |  1 +
>  xen/arch/x86/guest/hyperv/hyperv.c | 54 ++++++++++++++++++++++++++++++
>  xen/arch/x86/guest/hypervisor.c    |  8 +++++
>  xen/include/asm-x86/guest.h        |  1 +
>  xen/include/asm-x86/guest/hyperv.h | 45 +++++++++++++++++++++++++
>  7 files changed, 119 insertions(+)
>  create mode 100644 xen/arch/x86/guest/hyperv/Makefile
>  create mode 100644 xen/arch/x86/guest/hyperv/hyperv.c
>  create mode 100644 xen/include/asm-x86/guest/hyperv.h
>
> diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
> index 867de857e8..56513c771c 100644
> --- a/xen/arch/x86/Kconfig
> +++ b/xen/arch/x86/Kconfig
> @@ -164,6 +164,15 @@ endchoice
>  config GUEST
>         bool
>
> +config HYPERV_GUEST
> +       def_bool n
> +       select GUEST
> +       prompt "Hyper-V Guest"
> +       ---help---
> +         Support for Xen detecting when it is running under Hyper-V.
> +
> +         If unsure, say N.
> +
>  config XEN_GUEST
>         def_bool n
>         select GUEST
> diff --git a/xen/arch/x86/guest/Makefile b/xen/arch/x86/guest/Makefile
> index f63d64bbee..f164196772 100644
> --- a/xen/arch/x86/guest/Makefile
> +++ b/xen/arch/x86/guest/Makefile
> @@ -1,3 +1,4 @@
>  obj-y += hypervisor.o
>
> +subdir-$(CONFIG_HYPERV_GUEST) += hyperv
>  subdir-$(CONFIG_XEN_GUEST) += xen
> diff --git a/xen/arch/x86/guest/hyperv/Makefile 
> b/xen/arch/x86/guest/hyperv/Makefile
> new file mode 100644
> index 0000000000..68170109a9
> --- /dev/null
> +++ b/xen/arch/x86/guest/hyperv/Makefile
> @@ -0,0 +1 @@
> +obj-y += hyperv.o
> diff --git a/xen/arch/x86/guest/hyperv/hyperv.c 
> b/xen/arch/x86/guest/hyperv/hyperv.c
> new file mode 100644
> index 0000000000..7ab4b127f3
> --- /dev/null
> +++ b/xen/arch/x86/guest/hyperv/hyperv.c
> @@ -0,0 +1,54 @@
> +/******************************************************************************
> + * arch/x86/guest/hyperv/hyperv.c
> + *
> + * Support for detecting and running under Hyper-V.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; If not, see <http://www.gnu.org/licenses/>.
> + *
> + * Copyright (c) 2019 Microsoft.
> + */
> +#include <xen/init.h>
> +
> +#include <asm/guest.h>
> +
> +bool __init hyperv_probe(void)
> +{
> +    uint32_t eax, ebx, ecx, edx;
> +
> +    cpuid(0x40000000, &eax, &ebx, &ecx, &edx);
> +    if ( !((ebx == 0x7263694d) &&  /* "Micr" */
> +           (ecx == 0x666f736f) &&  /* "osof" */
> +           (edx == 0x76482074)) )  /* "t Hv" */
> +        return false;
> +
> +    cpuid(0x40000001, &eax, &ebx, &ecx, &edx);
> +    if ( eax != 0x31237648 )    /* Hv#1 */
> +        return false;
> +
> +    return true;
> +}
> +
> +struct hypervisor_ops hyperv_ops = {
> +    .name = "Hyper-V",
> +};
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * tab-width: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> diff --git a/xen/arch/x86/guest/hypervisor.c b/xen/arch/x86/guest/hypervisor.c
> index a666ad9526..17392d1ffa 100644
> --- a/xen/arch/x86/guest/hypervisor.c
> +++ b/xen/arch/x86/guest/hypervisor.c
> @@ -43,6 +43,14 @@ bool hypervisor_probe(void)
>      }
>  #endif
>

Add a comment here to point out that hyperv_probe() needs to be called
after xen_probe() to avoid a false positive due to viridian support.

> +#ifdef CONFIG_HYPERV_GUEST
> +    if ( hyperv_probe() )
> +    {
> +        hops = &hyperv_ops;
> +        return true;
> +    }
> +#endif
> +
>      return false;
>  }
>
> diff --git a/xen/include/asm-x86/guest.h b/xen/include/asm-x86/guest.h
> index 8e167165ae..94448606d4 100644
> --- a/xen/include/asm-x86/guest.h
> +++ b/xen/include/asm-x86/guest.h
> @@ -20,6 +20,7 @@
>  #define __X86_GUEST_H__
>
>  #include <asm/guest/hypercall.h>
> +#include <asm/guest/hyperv.h>
>  #include <asm/guest/hypervisor.h>
>  #include <asm/guest/pvh-boot.h>
>  #include <asm/guest/xen.h>
> diff --git a/xen/include/asm-x86/guest/hyperv.h 
> b/xen/include/asm-x86/guest/hyperv.h
> new file mode 100644
> index 0000000000..4b9cc5a836
> --- /dev/null
> +++ b/xen/include/asm-x86/guest/hyperv.h
> @@ -0,0 +1,45 @@
> +/******************************************************************************
> + * asm-x86/guest/hyperv.h
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms and conditions of the GNU General Public
> + * License, version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public
> + * License along with this program; If not, see 
> <http://www.gnu.org/licenses/>.
> + *
> + * Copyright (c) 2019 Microsoft.
> + */
> +
> +#ifndef __X86_GUEST_HYPERV_H__
> +#define __X86_GUEST_HYPERV_H__
> +
> +#ifdef CONFIG_HYPERV_GUEST
> +
> +#include <asm/guest/hypervisor.h>
> +
> +extern struct hypervisor_ops hyperv_ops;
> +
> +bool hyperv_probe(void);
> +
> +#else
> +
> +static inline bool hyperv_probe(void) { return false; }
> +
> +#endif /* CONFIG_HYPERV_GUEST */
> +#endif /* __X86_GUEST_HYPERV_H__ */
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * tab-width: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> --
> 2.20.1
>
>
> _______________________________________________
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> Xen-devel@xxxxxxxxxxxxxxxxxxxx
> https://lists.xenproject.org/mailman/listinfo/xen-devel

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