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From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: kevin.tian@intel.com, linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org, pasic@linux.ibm.com,
	iommu@lists.linux-foundation.org, sebastien.boeuf@intel.com,
	will@kernel.org, jasowang@redhat.com
Subject: Re: [PATCH v2 4/5] iommu/virtio: Pass end address to viommu_add_mapping()
Date: Mon, 29 Nov 2021 15:42:56 +0000	[thread overview]
Message-ID: <YaT1ACdwq1n4YBug@myrica> (raw)
In-Reply-To: <20211127180742-mutt-send-email-mst@kernel.org>

On Sat, Nov 27, 2021 at 06:09:56PM -0500, Michael S. Tsirkin wrote:
> > > -static int viommu_add_mapping(struct viommu_domain *vdomain, unsigned long iova,
> > > -			      phys_addr_t paddr, size_t size, u32 flags)
> > > +static int viommu_add_mapping(struct viommu_domain *vdomain, u64 iova, u64 end,
> > > +			      phys_addr_t paddr, u32 flags)
> > >  {
> > >  	unsigned long irqflags;
> > >  	struct viommu_mapping *mapping;
> 
> I am worried that API changes like that will cause subtle
> bugs since types of arguments change but not their
> number. If we forgot to update some callers it will all be messed up.
> 
> How about passing struct Range instead?

I gave struct range a try but it looks messier overall since it would only
be used to pass arguments. I think the update is safe enough because there
is one caller for viommu_add_mapping() and two for viommu_del_mappings(),
at the moment.

Thanks,
Jean

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: joro@8bytes.org, linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org, pasic@linux.ibm.com,
	Eric Auger <eric.auger@redhat.com>,
	iommu@lists.linux-foundation.org, sebastien.boeuf@intel.com,
	will@kernel.org
Subject: Re: [PATCH v2 4/5] iommu/virtio: Pass end address to viommu_add_mapping()
Date: Mon, 29 Nov 2021 15:42:56 +0000	[thread overview]
Message-ID: <YaT1ACdwq1n4YBug@myrica> (raw)
In-Reply-To: <20211127180742-mutt-send-email-mst@kernel.org>

On Sat, Nov 27, 2021 at 06:09:56PM -0500, Michael S. Tsirkin wrote:
> > > -static int viommu_add_mapping(struct viommu_domain *vdomain, unsigned long iova,
> > > -			      phys_addr_t paddr, size_t size, u32 flags)
> > > +static int viommu_add_mapping(struct viommu_domain *vdomain, u64 iova, u64 end,
> > > +			      phys_addr_t paddr, u32 flags)
> > >  {
> > >  	unsigned long irqflags;
> > >  	struct viommu_mapping *mapping;
> 
> I am worried that API changes like that will cause subtle
> bugs since types of arguments change but not their
> number. If we forgot to update some callers it will all be messed up.
> 
> How about passing struct Range instead?

I gave struct range a try but it looks messier overall since it would only
be used to pass arguments. I think the update is safe enough because there
is one caller for viommu_add_mapping() and two for viommu_del_mappings(),
at the moment.

Thanks,
Jean

_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

WARNING: multiple messages have this Message-ID (diff)
From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>,
	joro@8bytes.org, will@kernel.org, jasowang@redhat.com,
	virtualization@lists.linux-foundation.org,
	iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
	sebastien.boeuf@intel.com, kevin.tian@intel.com,
	pasic@linux.ibm.com
Subject: Re: [PATCH v2 4/5] iommu/virtio: Pass end address to viommu_add_mapping()
Date: Mon, 29 Nov 2021 15:42:56 +0000	[thread overview]
Message-ID: <YaT1ACdwq1n4YBug@myrica> (raw)
In-Reply-To: <20211127180742-mutt-send-email-mst@kernel.org>

On Sat, Nov 27, 2021 at 06:09:56PM -0500, Michael S. Tsirkin wrote:
> > > -static int viommu_add_mapping(struct viommu_domain *vdomain, unsigned long iova,
> > > -			      phys_addr_t paddr, size_t size, u32 flags)
> > > +static int viommu_add_mapping(struct viommu_domain *vdomain, u64 iova, u64 end,
> > > +			      phys_addr_t paddr, u32 flags)
> > >  {
> > >  	unsigned long irqflags;
> > >  	struct viommu_mapping *mapping;
> 
> I am worried that API changes like that will cause subtle
> bugs since types of arguments change but not their
> number. If we forgot to update some callers it will all be messed up.
> 
> How about passing struct Range instead?

I gave struct range a try but it looks messier overall since it would only
be used to pass arguments. I think the update is safe enough because there
is one caller for viommu_add_mapping() and two for viommu_del_mappings(),
at the moment.

Thanks,
Jean


  reply	other threads:[~2021-11-29 15:43 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-23 15:52 [PATCH v2 0/5] iommu/virtio: Add identity domains Jean-Philippe Brucker
2021-11-23 15:52 ` Jean-Philippe Brucker
2021-11-23 15:52 ` Jean-Philippe Brucker
2021-11-23 15:52 ` [PATCH v2 1/5] iommu/virtio: Add definitions for VIRTIO_IOMMU_F_BYPASS_CONFIG Jean-Philippe Brucker
2021-11-23 15:52   ` Jean-Philippe Brucker
2021-11-23 15:52   ` Jean-Philippe Brucker
2021-11-27  7:59   ` Eric Auger
2021-11-27  7:59     ` Eric Auger
2021-11-27  7:59     ` Eric Auger
2021-11-29 15:33     ` Jean-Philippe Brucker
2021-11-29 15:33       ` Jean-Philippe Brucker
2021-11-29 15:33       ` Jean-Philippe Brucker
2021-11-23 15:52 ` [PATCH v2 2/5] iommu/virtio: Support bypass domains Jean-Philippe Brucker
2021-11-23 15:52   ` Jean-Philippe Brucker
2021-11-23 15:52   ` Jean-Philippe Brucker
2021-11-27 16:18   ` Eric Auger
2021-11-27 16:18     ` Eric Auger
2021-11-27 16:18     ` Eric Auger
2021-11-29 15:36     ` Jean-Philippe Brucker
2021-11-29 15:36       ` Jean-Philippe Brucker
2021-11-29 15:36       ` Jean-Philippe Brucker
2021-11-23 15:53 ` [PATCH v2 3/5] iommu/virtio: Sort reserved regions Jean-Philippe Brucker
2021-11-23 15:53   ` Jean-Philippe Brucker
2021-11-23 15:53   ` Jean-Philippe Brucker
2021-11-27 17:09   ` Eric Auger
2021-11-27 17:09     ` Eric Auger
2021-11-27 17:09     ` Eric Auger
2021-11-23 15:53 ` [PATCH v2 4/5] iommu/virtio: Pass end address to viommu_add_mapping() Jean-Philippe Brucker
2021-11-23 15:53   ` Jean-Philippe Brucker
2021-11-23 15:53   ` Jean-Philippe Brucker
2021-11-27 17:09   ` Eric Auger
2021-11-27 17:09     ` Eric Auger
2021-11-27 17:09     ` Eric Auger
2021-11-27 23:09     ` Michael S. Tsirkin
2021-11-27 23:09       ` Michael S. Tsirkin
2021-11-27 23:09       ` Michael S. Tsirkin
2021-11-29 15:42       ` Jean-Philippe Brucker [this message]
2021-11-29 15:42         ` Jean-Philippe Brucker
2021-11-29 15:42         ` Jean-Philippe Brucker
2021-11-23 15:53 ` [PATCH v2 5/5] iommu/virtio: Support identity-mapped domains Jean-Philippe Brucker
2021-11-23 15:53   ` Jean-Philippe Brucker
2021-11-23 15:53   ` Jean-Philippe Brucker
2021-11-27 17:09   ` Eric Auger
2021-11-27 17:09     ` Eric Auger
2021-11-27 17:09     ` Eric Auger
2021-11-29 15:44     ` Jean-Philippe Brucker
2021-11-29 15:44       ` Jean-Philippe Brucker
2021-11-29 15:44       ` Jean-Philippe Brucker

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