linux-kernel - Re: [PATCH 09/10] vfio-pci: create an iommu mapping for msi address

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Date:	Tue, 26 Jan 2016 16:14:23 +0100
From:	Eric Auger <eric.auger@...aro.org>
To:	kbuild test robot <lkp@...el.com>
Cc:	kbuild-all@...org, eric.auger@...com, alex.williamson@...hat.com,
	will.deacon@....com, christoffer.dall@...aro.org,
	marc.zyngier@....com, linux-arm-kernel@...ts.infradead.org,
	kvmarm@...ts.cs.columbia.edu, kvm@...r.kernel.org,
	Bharat.Bhushan@...escale.com, pranav.sawargaonkar@...il.com,
	p.fedin@...sung.com, suravee.suthikulpanit@....com,
	linux-kernel@...r.kernel.org, patches@...aro.org,
	iommu@...ts.linux-foundation.org
Subject: Re: [PATCH 09/10] vfio-pci: create an iommu mapping for msi address

Hi,
On 01/26/2016 03:43 PM, kbuild test robot wrote:
> Hi Eric,
> 
> [auto build test WARNING on v4.5-rc1]
> [also build test WARNING on next-20160125]
> [cannot apply to iommu/next]
> [if your patch is applied to the wrong git tree, please drop us a note to help improving the system]
> 
> url:    https://github.com/0day-ci/linux/commits/Eric-Auger/KVM-PCIe-MSI-passthrough-on-ARM-ARM64/20160126-211921
> config: i386-allmodconfig (attached as .config)
> reproduce:
>         # save the attached .config to linux build tree
>         make ARCH=i386 
> 
> All warnings (new ones prefixed by >>):
> 
>    drivers/vfio/pci/vfio_pci_intrs.c: In function 'vfio_set_mapped_msi_addr':
>>> drivers/vfio/pci/vfio_pci_intrs.c:324:43: warning: left shift count >= width of type [-Wshift-count-overflow]
>      msi_addr = (phys_addr_t)(msg.address_hi) << 32 |
>                                               ^
>>> drivers/vfio/pci/vfio_pci_intrs.c:333:34: warning: right shift count >= width of type [-Wshift-count-overflow]
>      msg.address_hi = (u32)(msi_iova >> 32);
I definitively need to revisit that code. I Better understand Alex'
comment now :-(

Thanks

Eric
>                                      ^
> 
> vim +324 drivers/vfio/pci/vfio_pci_intrs.c
> 
>    318		dma_addr_t msi_iova;
>    319		struct vfio_group *group = vdev->vfio_group;
>    320		struct msi_msg msg;
>    321		int ret;
>    322	
>    323		get_cached_msi_msg(irq, &msg);
>  > 324		msi_addr = (phys_addr_t)(msg.address_hi) << 32 |
>    325				(phys_addr_t)(msg.address_lo);
>    326	
>    327		ret = vfio_group_alloc_map_reserved_iova(group, msi_addr,
>    328							 IOMMU_WRITE, &msi_iova);
>    329		if (ret)
>    330			goto out;
>    331	
>    332		/* Re-program the msi-address with the iova */
>  > 333		msg.address_hi = (u32)(msi_iova >> 32);
>    334		msg.address_lo = (u32)(msi_iova & 0xffffffff);
>    335		pci_write_msi_msg(irq, &msg);
>    336	
> 
> ---
> 0-DAY kernel test infrastructure                Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
>