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Subject: Re: [PATCH v2 2/2] KVM: x86: Implement the arch-specific hook to
 report the VM UUID
To:     Filippo Sironi <sironi@amazon.de>, <linux-kernel@vger.kernel.org>,
        <kvm@vger.kernel.org>, <borntraeger@de.ibm.com>,
        <boris.ostrovsky@oracle.com>, <cohuck@redhat.com>,
        <konrad.wilk@oracle.com>, <xen-devel@lists.xenproject.org>,
        <vasu.srinivasan@oracle.com>
References: <1539078879-4372-1-git-send-email-sironi@amazon.de>
 <1557847002-23519-1-git-send-email-sironi@amazon.de>
 <1557847002-23519-3-git-send-email-sironi@amazon.de>
From:   Alexander Graf <graf@amazon.com>
Message-ID: <f51a6a84-b21c-ab75-7e30-bfbe2ac6b98b@amazon.com>
Date:   Thu, 16 May 2019 06:56:01 -0700
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On 14.05.19 08:16, Filippo Sironi wrote:
> On x86, we report the UUID in DMI System Information (i.e., DMI Type 1)
> as VM UUID.
> 
> Signed-off-by: Filippo Sironi <sironi@amazon.de>
> ---
>  arch/x86/kernel/kvm.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index 5c93a65ee1e5..441cab08a09d 100644
> --- a/arch/x86/kernel/kvm.c
> +++ b/arch/x86/kernel/kvm.c
> @@ -25,6 +25,7 @@
>  #include <linux/kernel.h>
>  #include <linux/kvm_para.h>
>  #include <linux/cpu.h>
> +#include <linux/dmi.h>
>  #include <linux/mm.h>
>  #include <linux/highmem.h>
>  #include <linux/hardirq.h>
> @@ -694,6 +695,12 @@ bool kvm_para_available(void)
>  }
>  EXPORT_SYMBOL_GPL(kvm_para_available);
>  
> +const char *kvm_para_get_uuid(void)
> +{
> +	return dmi_get_system_info(DMI_PRODUCT_UUID);

This adds a new dependency on CONFIG_DMI. Probably best to guard it with
an #if IS_ENABLED(CONFIG_DMI).

The concept seems sound though.


Alex

> +}
> +EXPORT_SYMBOL_GPL(kvm_para_get_uuid);
> +
>  unsigned int kvm_arch_para_features(void)
>  {
>  	return cpuid_eax(kvm_cpuid_base() | KVM_CPUID_FEATURES);
>