Re: [PATCH v2] vfio-pci: Allow to mmap sub-page MMIO BARs if the mmio page is exclusive

2016-05-11 Thread Yongji Xie
On 2016/5/11 23:10, Bjorn Helgaas wrote: On Wed, May 11, 2016 at 07:34:19PM +0800, Yongji Xie wrote: Current vfio-pci implementation disallows to mmap sub-page(size < PAGE_SIZE) MMIO BARs because these BARs' mmio page may be shared with other BARs. This will cause some performance issues when w

Re: [PATCH v2] vfio-pci: Allow to mmap sub-page MMIO BARs if the mmio page is exclusive

2016-05-11 Thread Bjorn Helgaas
On Wed, May 11, 2016 at 07:34:19PM +0800, Yongji Xie wrote: > Current vfio-pci implementation disallows to mmap > sub-page(size < PAGE_SIZE) MMIO BARs because these BARs' mmio > page may be shared with other BARs. This will cause some > performance issues when we passthrough a PCI device with > thi

[PATCH v2] vfio-pci: Allow to mmap sub-page MMIO BARs if the mmio page is exclusive

2016-05-11 Thread Yongji Xie
Current vfio-pci implementation disallows to mmap sub-page(size < PAGE_SIZE) MMIO BARs because these BARs' mmio page may be shared with other BARs. This will cause some performance issues when we passthrough a PCI device with this kind of BARs. Guest will be not able to handle the mmio accesses to