Re: [PATCH 02/11] early PV on HVM

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Mon, May 10, 2010 at 03:20:38PM +0100, Stefano Stabellini wrote:
> From: Sheng Yang <sheng@linux.intel.com>
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> Signed-off-by: Sheng Yang <sheng@linux.intel.com>
> Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
> ---
>  arch/x86/include/asm/xen/hypervisor.h |    2 +
>  arch/x86/kernel/setup.c               |    2 +
>  arch/x86/xen/enlighten.c              |   87 +++++++++++++++++++++++++++++++++
>  drivers/input/xen-kbdfront.c          |    2 +-
>  drivers/video/xen-fbfront.c           |    2 +-
>  drivers/xen/xenbus/xenbus_probe.c     |   14 ++++-
>  6 files changed, 104 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/include/asm/xen/hypervisor.h b/arch/x86/include/asm/xen/hypervisor.h
> index d5b7e90..128bc14 100644
> --- a/arch/x86/include/asm/xen/hypervisor.h
> +++ b/arch/x86/include/asm/xen/hypervisor.h
> @@ -45,8 +45,10 @@ enum xen_domain_type {
>  
>  #ifdef CONFIG_XEN
>  extern enum xen_domain_type xen_domain_type;
> +extern void xen_guest_init(void);
>  #else
>  #define xen_domain_type		XEN_NATIVE
> +#define xen_guest_init() do { } while (0)
>  #endif
>  
>  #define xen_domain()		(xen_domain_type != XEN_NATIVE)
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 2a34f9c..cd38ca0 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -102,6 +102,7 @@
>  
>  #include <asm/paravirt.h>
>  #include <asm/hypervisor.h>
> +#include <asm/xen/hypervisor.h>
>  
>  #include <asm/percpu.h>
>  #include <asm/topology.h>
> @@ -1014,6 +1015,7 @@ void __init setup_arch(char **cmdline_p)
>  	probe_nr_irqs_gsi();
>  
>  	kvm_guest_init();
> +	xen_guest_init();

Upstream has this new mechanism for detecting hypervisors with a fancy
data structure that makes '->detect' and other things. You might want to
take that under consideration as when you post this patch upstream
upstream they are going to ask why you aren't using it.

>  
>  	e820_reserve_resources();
>  	e820_mark_nosave_regions(max_low_pfn);
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index dfbf70e..723f53c 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -32,6 +32,8 @@
>  #include <xen/interface/version.h>
>  #include <xen/interface/physdev.h>
>  #include <xen/interface/vcpu.h>
> +#include <xen/interface/memory.h>
> +#include <xen/interface/hvm/hvm_op.h>
>  #include <xen/features.h>
>  #include <xen/page.h>
>  #include <xen/hvc-console.h>
> @@ -1189,3 +1191,88 @@ asmlinkage void __init xen_start_kernel(void)
>  	x86_64_start_reservations((char *)__pa_symbol(&boot_params));
>  #endif
>  }
> +
> +static uint32_t xen_cpuid_base(void)
> +{
> +	uint32_t base, eax, ebx, ecx, edx;
> +	char signature[13];
> +
> +	for (base = 0x40000000; base < 0x40010000; base += 0x100) {
> +		cpuid(base, &eax, &ebx, &ecx, &edx);
> +		*(uint32_t*)(signature + 0) = ebx;
> +		*(uint32_t*)(signature + 4) = ecx;
> +		*(uint32_t*)(signature + 8) = edx;
> +		signature[12] = 0;
> +
> +		if (!strcmp("XenVMMXenVMM", signature) && ((eax - base) >= 2))
> +			return base;
> +	}
> +
> +	return 0;
> +}

And this seems to be used by the VMWare/HyperV detection engine too.

Maybe make another patch that makes a generic cpuid function that can be
shared with VMWAre/HyperV/Xen?