linux-kernel - Re: [PATCH v19 05/20] s390/vfio-ap: refresh guest's APCB by filtering AP resources assigned to mdev

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Date:   Mon, 16 May 2022 13:50:48 -0400
From:   "Jason J. Herne" <jjherne@...ux.ibm.com>
To:     Tony Krowiak <akrowiak@...ux.ibm.com>, linux-s390@...r.kernel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     freude@...ux.ibm.com, borntraeger@...ibm.com, cohuck@...hat.com,
        mjrosato@...ux.ibm.com, pasic@...ux.ibm.com,
        alex.williamson@...hat.com, kwankhede@...dia.com,
        fiuczy@...ux.ibm.com
Subject: Re: [PATCH v19 05/20] s390/vfio-ap: refresh guest's APCB by filtering
 AP resources assigned to mdev

On 5/16/22 13:13, Tony Krowiak wrote:
> 
> 
> On 5/16/22 12:36 PM, Jason J. Herne wrote:
>> On 4/4/22 18:10, Tony Krowiak wrote:
>>> |@@ -1306,8 +1392,6 @@ static int vfio_ap_mdev_set_kvm(struct ap_matrix_mdev 
>>> *matrix_mdev, kvm_get_kvm(kvm); matrix_mdev->kvm = kvm; - 
>>> memcpy(&matrix_mdev->shadow_apcb, &matrix_mdev->matrix, - sizeof(struct ap_matrix)); 
>>> kvm_arch_crypto_set_masks(kvm, matrix_mdev->shadow_apcb.apm, 
>>> matrix_mdev->shadow_apcb.aqm, matrix_mdev->shadow_apcb.adm);|
>>
>> This looks like an unrelated change. Does this snippet really belong to this patch?
> 
> It's kind of hard to tell which snippet you are talking about without the patch context, 
> but I assume you are referring to the removal of the memcpy statement in the 
> vfio_ap_mdev_set_kvm() function in which case this snippet belongs with this patch.
> 
> This patch introduces a function that filters the contents of the matrix_mdev->matrix to 
> ensure that the matrix_mdev->shadow_apcb contains only queues that are bound to the 
> vfio_ap device driver. The filtering function is called whenever an adapter, domain or 
> control domain is assigned or unassigned, so it is no longer necessary to copy the 
> contents of matrix_mdev->matrix into matrix_mdev->shadow_apcb before setting the masks in 
> the guest; that will have already been done by the filter function.
> 
> 

I was apparently a little overzealous with my trimming. Yes, you are correct. Thanks for
the explanation.

Reviewed-by: Jason J. Herne <jjherne@...ux.ibm.com>


-- 
-- Jason J. Herne (jjherne@...ux.ibm.com)