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

From: Eric Auger
Date: Tue Jan 26 2016 - 10:14:49 EST


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
>
> ---
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>