Re: [RFC PATCH 1/3] arch/x86: add ACRN hypervisor guest

[Sean Christopherson <sean.j.christopherson@intel.com>]

On Thu, Mar 07, 2019 at 10:04:09AM +0800, Zhao Yakui wrote:
> ACRN is one open-source hypervisour, which is maintained by Linux
> foundation. This is to add the para-virtualization support so that
> it allows to enable the Linux guest on acrn-hypervisor.
> 
> This adds x86_hyper_acrn into supported hypervisors array, which
> enables ACRN services guest running on ACRN hypervisor. It is
> restricted to X86_64.
> 
> Signed-off-by: Jason Chen CJ <jason.cj.chen@intel.com>
> Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
> ---
>  arch/x86/Kconfig                  |  8 ++++++++
>  arch/x86/include/asm/hypervisor.h |  1 +
>  arch/x86/kernel/cpu/Makefile      |  1 +
>  arch/x86/kernel/cpu/acrn.c        | 36 ++++++++++++++++++++++++++++++++++++
>  arch/x86/kernel/cpu/hypervisor.c  |  4 ++++
>  5 files changed, 50 insertions(+)
>  create mode 100644 arch/x86/kernel/cpu/acrn.c
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 90b562a..c7b64e7 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -843,6 +843,14 @@ config JAILHOUSE_GUEST
>  	  cell. You can leave this option disabled if you only want to start
>  	  Jailhouse and run Linux afterwards in the root cell.
>  
> +config ACRN

My personal preference would be to use ACRN_GUEST.  Inevitably there will
be a need to wrap ACRN code with an ifdef, and seeing "GUEST" in such
cases immediately lets readers know the code in question is related to
running as a guest without having to remember that ACRN is a hypervisor.
This is especially true for readers that have never heard of ACRN.

> +	bool "Enable services on ACRN hypervisor"
> +	depends on X86_64 && PARAVIRT
> +	help
> +	  This option allows to run Linux as guest in ACRN hypervisor.
> +	  It is needed if you want to run ACRN services linux on top of
> +	  ACRN hypervisor.
> +
>  endif #HYPERVISOR_GUEST
>  
>  source "arch/x86/Kconfig.cpu"
> diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
> index 8c5aaba..50a30f6 100644
> --- a/arch/x86/include/asm/hypervisor.h
> +++ b/arch/x86/include/asm/hypervisor.h
> @@ -29,6 +29,7 @@ enum x86_hypervisor_type {
>  	X86_HYPER_XEN_HVM,
>  	X86_HYPER_KVM,
>  	X86_HYPER_JAILHOUSE,
> +	X86_HYPER_ACRN,
>  };
>  
>  #ifdef CONFIG_HYPERVISOR_GUEST
> diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
> index cfd24f9..cde1436 100644
> --- a/arch/x86/kernel/cpu/Makefile
> +++ b/arch/x86/kernel/cpu/Makefile
> @@ -44,6 +44,7 @@ obj-$(CONFIG_X86_CPU_RESCTRL)		+= resctrl/
>  obj-$(CONFIG_X86_LOCAL_APIC)		+= perfctr-watchdog.o
>  
>  obj-$(CONFIG_HYPERVISOR_GUEST)		+= vmware.o hypervisor.o mshyperv.o
> +obj-$(CONFIG_ACRN)			+= acrn.o
>  
>  ifdef CONFIG_X86_FEATURE_NAMES
>  quiet_cmd_mkcapflags = MKCAP   $@
> diff --git a/arch/x86/kernel/cpu/acrn.c b/arch/x86/kernel/cpu/acrn.c
> new file mode 100644
> index 0000000..ddeaafb
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/acrn.c
> @@ -0,0 +1,36 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ACRN hypervisor support
> + *
> + * Copyright (C) 2019 Intel Corporation. All rights reserved.
> + *
> + * Jason Chen CJ <jason.cj.chen@intel.com>
> + * Zhao Yakui <yakui.zhao@intel.com>
> + *
> + */
> +
> +#include <asm/hypervisor.h>
> +
> +static uint32_t __init acrn_detect(void)
> +{
> +	return hypervisor_cpuid_base("ACRNACRNACRN\0\0", 0);
> +}
> +
> +static void __init acrn_init_platform(void)
> +{
> +}
> +
> +static bool acrn_x2apic_available(void)
> +{
> +	/* do not support x2apic */
> +	return false;
> +}
> +
> +const struct hypervisor_x86 x86_hyper_acrn = {
> +	.name                   = "ACRN",
> +	.detect                 = acrn_detect,
> +	.type			= X86_HYPER_ACRN,
> +	.init.init_platform     = acrn_init_platform,
> +	.init.x2apic_available  = acrn_x2apic_available,
> +};
> +EXPORT_SYMBOL(x86_hyper_acrn);
> diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c
> index 479ca47..5a6f072 100644
> --- a/arch/x86/kernel/cpu/hypervisor.c
> +++ b/arch/x86/kernel/cpu/hypervisor.c
> @@ -32,6 +32,7 @@ extern const struct hypervisor_x86 x86_hyper_xen_pv;
>  extern const struct hypervisor_x86 x86_hyper_xen_hvm;
>  extern const struct hypervisor_x86 x86_hyper_kvm;
>  extern const struct hypervisor_x86 x86_hyper_jailhouse;
> +extern const struct hypervisor_x86 x86_hyper_acrn;
>  
>  static const __initconst struct hypervisor_x86 * const hypervisors[] =
>  {
> @@ -49,6 +50,9 @@ static const __initconst struct hypervisor_x86 * const hypervisors[] =
>  #ifdef CONFIG_JAILHOUSE_GUEST
>  	&x86_hyper_jailhouse,
>  #endif
> +#ifdef CONFIG_ACRN
> +	&x86_hyper_acrn,
> +#endif
>  };
>  
>  enum x86_hypervisor_type x86_hyper_type;
> -- 
> 2.7.4
>