Re: [Xen-devel] [PATCH v4 8/8] x86: introduce CONFIG_HYPERV and detection code

["Durrant, Paul" <pdurrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Xen-devel <xen-devel-bounces@xxxxxxxxxxxxxxxxxxxx> On Behalf Of Wei
> Liu
> Sent: 21 November 2019 19:51
> To: Xen Development List <xen-devel@xxxxxxxxxxxxxxxxxxxx>
> Cc: Wei Liu <liuwe@xxxxxxxxxxxxx>; Wei Liu <wl@xxxxxxx>; Andrew Cooper
> <andrew.cooper3@xxxxxxxxxx>; Michael Kelley <mikelley@xxxxxxxxxxxxx>; Jan
> Beulich <jbeulich@xxxxxxxx>; Roger Pau Monné <roger.pau@xxxxxxxxxx>
> Subject: [Xen-devel] [PATCH v4 8/8] x86: introduce CONFIG_HYPERV and
> detection code
> 
> 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.
> 
> Take the chance to fix XEN_GUEST in Kconfig.

Would this fix be better in your earlier renaming patch?

> 
> Signed-off-by: Wei Liu <liuwe@xxxxxxxxxxxxx>

Either way...

Reviewed-by: Paul Durrant <pdurrant@xxxxxxxxxx>

> ---
> Changes in V4:
> 1. Add comment regarding order of probe functions.
> 2. Adapt to changes in previous patches.
> ---
>  xen/arch/x86/Kconfig               | 11 ++++--
>  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 | 43 ++++++++++++++++++++++++
>  7 files changed, 117 insertions(+), 2 deletions(-)
>  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..0a02b6ee3f 100644
> --- a/xen/arch/x86/Kconfig
> +++ b/xen/arch/x86/Kconfig
> @@ -164,10 +164,17 @@ endchoice
>  config GUEST
>       bool
> 
> +config HYPERV_GUEST
> +     bool "Hyper-V Guest"
> +     select GUEST
> +     ---help---
> +       Support for Xen detecting when it is running under Hyper-V.
> +
> +       If unsure, say N.
> +
>  config XEN_GUEST
> -     def_bool n
> +     bool "Xen Guest"
>       select GUEST
> -     prompt "Xen Guest"
>       ---help---
>         Support for Xen detecting when it is running under Xen.
> 
> 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..916e08ff89
> --- /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>
> +
> +static const struct hypervisor_ops hyperv_ops = {
> +    .name = "Hyper-V",
> +};
> +
> +const struct hypervisor_ops * __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 NULL;
> +
> +    cpuid(0x40000001, &eax, &ebx, &ecx, &edx);
> +    if ( eax != 0x31237648 )    /* Hv#1 */
> +        return NULL;
> +
> +    return &hyperv_ops;
> +}
> +
> +/*
> + * 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 a067cacecb..c293e185cc 100644
> --- a/xen/arch/x86/guest/hypervisor.c
> +++ b/xen/arch/x86/guest/hypervisor.c
> @@ -39,6 +39,14 @@ const struct hypervisor_ops *hypervisor_probe(void)
>      if ( hops )
>          goto out;
> 
> +    /*
> +     * Detection of Hyper-V must come after Xen to avoid false positive
> due
> +     * to viridian support
> +     */
> +    hops = hyperv_probe();
> +    if ( hops )
> +        goto out;
> +
>   out:
>      return hops;
>  }
> 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..3f88b94c77
> --- /dev/null
> +++ b/xen/include/asm-x86/guest/hyperv.h
> @@ -0,0 +1,43 @@
> +/************************************************************************
> ******
> + * 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>
> +
> +const struct hypervisor_ops *hyperv_probe(void);
> +
> +#else
> +
> +static inline const struct hypervisor_ops *hyperv_probe(void) { return
> NULL; }
> +
> +#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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