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Subject: Re: [PATCH v5 13/15] vfio/pci: Expose PCIe PASID capability to guest
To:     Liu Yi L <yi.l.liu@intel.com>, alex.williamson@redhat.com,
        baolu.lu@linux.intel.com, joro@8bytes.org
Cc:     kevin.tian@intel.com, jacob.jun.pan@linux.intel.com,
        ashok.raj@intel.com, jun.j.tian@intel.com, yi.y.sun@intel.com,
        jean-philippe@linaro.org, peterx@redhat.com, hao.wu@intel.com,
        stefanha@gmail.com, iommu@lists.linux-foundation.org,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1594552870-55687-1-git-send-email-yi.l.liu@intel.com>
 <1594552870-55687-14-git-send-email-yi.l.liu@intel.com>
From:   Auger Eric <eric.auger@redhat.com>
Message-ID: <63d4c058-246d-1a11-af66-e97fd5ec9bd3@redhat.com>
Date:   Mon, 20 Jul 2020 14:35:26 +0200
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Yi,

On 7/12/20 1:21 PM, Liu Yi L wrote:
> This patch exposes PCIe PASID capability to guest for assigned devices.
> Existing vfio_pci driver hides it from guest by setting the capability
> length as 0 in pci_ext_cap_length[].
> 
> And this patch only exposes PASID capability for devices which has PCIe
> PASID extended struture in its configuration space. So VFs, will will
s/will//
> not see PASID capability on VFs as VF doesn't implement PASID extended
suggested rewording: VFs will not expose the PASID capability as they do
not implement the PASID extended structure in their config space?
> structure in its configuration space. For VF, it is a TODO in future.
> Related discussion can be found in below link:
> 
> https://lkml.org/lkml/2020/4/7/693

> 
> Cc: Kevin Tian <kevin.tian@intel.com>
> CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Cc: Alex Williamson <alex.williamson@redhat.com>
> Cc: Eric Auger <eric.auger@redhat.com>
> Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
> Cc: Joerg Roedel <joro@8bytes.org>
> Cc: Lu Baolu <baolu.lu@linux.intel.com>
> Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> ---
> v1 -> v2:
> *) added in v2, but it was sent in a separate patchseries before
> ---
>  drivers/vfio/pci/vfio_pci_config.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
> index d98843f..07ff2e6 100644
> --- a/drivers/vfio/pci/vfio_pci_config.c
> +++ b/drivers/vfio/pci/vfio_pci_config.c
> @@ -95,7 +95,7 @@ static const u16 pci_ext_cap_length[PCI_EXT_CAP_ID_MAX + 1] = {
>  	[PCI_EXT_CAP_ID_LTR]	=	PCI_EXT_CAP_LTR_SIZEOF,
>  	[PCI_EXT_CAP_ID_SECPCI]	=	0,	/* not yet */
>  	[PCI_EXT_CAP_ID_PMUX]	=	0,	/* not yet */
> -	[PCI_EXT_CAP_ID_PASID]	=	0,	/* not yet */
> +	[PCI_EXT_CAP_ID_PASID]	=	PCI_EXT_CAP_PASID_SIZEOF,
>  };
>  
>  /*
> 
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thanks

Eric