Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 16 May 2019 09:14:29 -0700
From:   Jacob Pan <jacob.jun.pan@linux.intel.com>
To:     Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Cc:     iommu@lists.linux-foundation.org,
        LKML <linux-kernel@vger.kernel.org>,
        Joerg Roedel <joro@8bytes.org>,
        David Woodhouse <dwmw2@infradead.org>,
        Eric Auger <eric.auger@redhat.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        "Tian, Kevin" <kevin.tian@intel.com>,
        Raj Ashok <ashok.raj@intel.com>,
        Andriy Shevchenko <andriy.shevchenko@linux.intel.com>,
        jacob.jun.pan@linux.intel.com
Subject: Re: [PATCH v3 09/16] iommu: Introduce guest PASID bind function
Message-ID: <20190516091429.6d06f7e1@jacob-builder>
In-Reply-To: <d652546a-c6ca-1cc6-1924-b016bd81a792@arm.com>
References: <1556922737-76313-1-git-send-email-jacob.jun.pan@linux.intel.com>
        <1556922737-76313-10-git-send-email-jacob.jun.pan@linux.intel.com>
        <d652546a-c6ca-1cc6-1924-b016bd81a792@arm.com>
Organization: OTC
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, 16 May 2019 15:14:40 +0100
Jean-Philippe Brucker <jean-philippe.brucker@arm.com> wrote:

> Hi Jacob,
> 
> On 03/05/2019 23:32, Jacob Pan wrote:
> > +/**
> > + * struct gpasid_bind_data - Information about device and guest
> > PASID binding
> > + * @gcr3:	Guest CR3 value from guest mm
> > + * @pasid:	Process address space ID used for the guest mm
> > + * @addr_width:	Guest address width. Paging mode can also
> > be derived.
> > + */
> > +struct gpasid_bind_data {
> > +	__u64 gcr3;
> > +	__u32 pasid;
> > +	__u32 addr_width;
> > +	__u32 flags;
> > +#define	IOMMU_SVA_GPASID_SRE	BIT(0) /* supervisor
> > request */
> > +	__u8 padding[4];
> > +};  
> 
> Could you wrap this structure into a generic one like we now do for
> bind_pasid_table? It would make the API easier to extend, because if
> we ever add individual PASID bind on Arm (something I'd like to do for
> virtio-iommu, eventually) it will have different parameters, as our
> PASID table entry has a lot of fields describing the page table
> format.
> 
> Maybe something like the following would do?
> 
> struct gpasid_bind_data {
> #define IOMMU_GPASID_BIND_VERSION_1 1
> 	__u32 version;
> #define IOMMU_GPASID_BIND_FORMAT_INTEL_VTD	1
> 	__u32 format;
> 	union {
> 		// the current gpasid_bind_data:
> 		struct gpasid_bind_intel_vtd vtd;
> 	};
> };
> 
OK, sounds great.