On 02.06.16 14:32, Peter Maydell wrote: > On 2 June 2016 at 13:26, Bogdan Purcareata <bogdan.purcare...@nxp.com> wrote: >> A PCI device is marked either as coherent or non-coherent based on the pcie >> controller "dma-coherent" property. This is further used when configuring the >> IOMMU ops for the device DMA resources (e.g. descriptor rings, for e1000e). >> >> This dma-coherent property needs to be configured in the guest environment, >> in case there's a directly assigned VFIO PCI device. Since the guest only >> receives one emulated pcie controller bus - regardless of the host >> configuration - add this property if there's at least one host pcie host >> controller that is DMA coherent (this implies that the host interconnect >> is coherent as well). > > This patch seems to change the property of the emulated PCIe controller > based on the host PCIe controller even if we're not doing any PCIe > passthrough at all. That seems definitely wrong to me. > > (Should the purely-emulated case be marked DMA-coherent anyway? > I forget the fiddly details...)
I do too, let's involve a few people who know :). Not exposing it as coherent is definitely wrong, but whether "dma-coherent" is the right choice I don't know. Alex
