linux-kernel - Re: [PATCH 7/9] xen/x86: hook up xen

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Message-ID: <d9b6e98c-4e75-73f3-1e6d-42df300cfd49@suse.com>
Date:   Thu, 23 Sep 2021 17:10:50 +0200
From:   Jan Beulich <jbeulich@...e.com>
To:     Juergen Gross <jgross@...e.com>
Cc:     Stefano Stabellini <sstabellini@...nel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        "xen-devel@...ts.xenproject.org" <xen-devel@...ts.xenproject.org>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>
Subject: Re: [PATCH 7/9] xen/x86: hook up xen_banner() also for PVH

On 23.09.2021 16:59, Juergen Gross wrote:
> On 07.09.21 12:11, Jan Beulich wrote:
>> This was effectively lost while dropping PVHv1 code. Move the function
>> and arrange for it to be called the same way as done in PV mode. Clearly
>> this then needs re-introducing the XENFEAT_mmu_pt_update_preserve_ad
>> check that was recently removed, as that's a PV-only feature.
>>
>> Signed-off-by: Jan Beulich <jbeulich@...e.com>
>>
>> --- a/arch/x86/xen/enlighten.c
>> +++ b/arch/x86/xen/enlighten.c
>> @@ -261,6 +261,18 @@ int xen_vcpu_setup(int cpu)
>>   	return ((per_cpu(xen_vcpu, cpu) == NULL) ? -ENODEV : 0);
>>   }
>>   
>> +void __init xen_banner(void)
>> +{
>> +	unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
>> +	struct xen_extraversion extra;
> 
> Please add a blank line here.

Oops.

>> +	HYPERVISOR_xen_version(XENVER_extraversion, &extra);
>> +
>> +	pr_info("Booting paravirtualized kernel on %s\n", pv_info.name);
> 
> Is this correct? I don't think the kernel needs to be paravirtualized
> with PVH (at least not to the same extend as for PV).

What else do you suggest the message to say? Simply drop
"paravirtualized"? To some extent it is applicable imo, further
qualified by pv_info.name. And that's how it apparently was with
PVHv1.

Jan