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To:     Yan Zhao <yan.y.zhao@intel.com>, Cornelia Huck <cohuck@redhat.com>
Cc:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        alex.williamson@redhat.com, zhenyuw@linux.intel.com,
        zhi.a.wang@intel.com, kevin.tian@intel.com, shaopeng.he@intel.com,
        yi.l.liu@intel.com, xin.zeng@intel.com, hang.yuan@intel.com
Subject: Re: [RFC PATCH v4 04/10] vfio/pci: let vfio_pci know number of
 vendor regions and vendor irqs
In-Reply-To: <20200605021542.GG12300@joy-OptiPlex-7040>
References: <20200518024202.13996-1-yan.y.zhao@intel.com>
 <20200518024944.14263-1-yan.y.zhao@intel.com>
 <20200604172515.614e9864.cohuck@redhat.com>
 <20200605021542.GG12300@joy-OptiPlex-7040>
From:   David Edmondson <dme@dme.org>
Date:   Thu, 11 Jun 2020 13:31:05 +0100
Message-ID: <m23671943a.fsf@dme.org>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
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On Thursday, 2020-06-04 at 22:15:42 -04, Yan Zhao wrote:

> On Thu, Jun 04, 2020 at 05:25:15PM +0200, Cornelia Huck wrote:
>> On Sun, 17 May 2020 22:49:44 -0400
>> Yan Zhao <yan.y.zhao@intel.com> wrote:
>> 
>> > This allows a simpler VFIO_DEVICE_GET_INFO ioctl in vendor driver
>> > 
>> > Cc: Kevin Tian <kevin.tian@intel.com>
>> > Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
>> > ---
>> >  drivers/vfio/pci/vfio_pci.c         | 23 +++++++++++++++++++++--
>> >  drivers/vfio/pci/vfio_pci_private.h |  2 ++
>> >  include/linux/vfio.h                |  3 +++
>> >  3 files changed, 26 insertions(+), 2 deletions(-)
>> > 
>> > diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
>> > index 290b7ab55ecf..30137c1c5308 100644
>> > --- a/drivers/vfio/pci/vfio_pci.c
>> > +++ b/drivers/vfio/pci/vfio_pci.c
>> > @@ -105,6 +105,24 @@ void *vfio_pci_vendor_data(void *device_data)
>> >  }
>> >  EXPORT_SYMBOL_GPL(vfio_pci_vendor_data);
>> >  
>> > +int vfio_pci_set_vendor_regions(void *device_data, int num_vendor_regions)
>> > +{
>> > +	struct vfio_pci_device *vdev = device_data;
>> > +
>> > +	vdev->num_vendor_regions = num_vendor_regions;
>> 
>> Do we need any kind of sanity check here, in case this is called with a
>> bogus value?
>>
> you are right. it at least needs to be >=0.
> maybe type of "unsigned int" is more appropriate for num_vendor_regions.
> we don't need to check its max value as QEMU would check it.

That seems like a bad precedent - the caller may not be QEMU.

dme.
-- 
I'm not the reason you're looking for redemption.