At 08/22/2011 02:23 PM, Avi Kivity Write: > On 08/22/2011 06:13 AM, Wen Congyang wrote: >> At 08/19/2011 11:26 PM, Avi Kivity Write: >> > On 08/18/2011 10:12 PM, Wen Congyang wrote: >> >> >> >> >> >> The following patch can fix this problem, but I'm not sure >> whether it >> >> >> is right. >> >> > >> >> > It's correct but insufficient, the filtering code >> (pci_bridge_filter) >> >> > needs to be updated to use the memory API. >> >> >> >> I read the function pci_bridge_filter(), and the function only read >> >> PCI bridge's config space(command, base and limit). If base> limit, >> >> it will set addr to PCI_BAR_UNMAPPED. >> >> >> >> I do not find anything that needs to updated to use the memory API. >> > >> > Currently it doesn't do any filtering at all. Bridges need to >> create a >> > new address space, then attach aliases of this region >> (corresponding to >> > the filtered area and to the legacy vga space) to the parent bus' >> > address space. >> >> Hmm, does this problem exist before memory API is introduced? > > Yes. There was code to handle it, but I don't think it was correct. > >> >> > >> >> I add a scsi controller on pci bus1, and a scsi disk on this >> controller. >> >> I can read and write this disk, and I do not meet any problem. >> >> >> > >> > However, filtering doesn't work. You could put a BAR outside the >> > filtered area and it would be visible to the guest. >> >> How to put a BAR outside the filtered area and confirm whether it >> would be >> virible to the guest? >> >> > > > You could use something like kvm-unit-tests.git to write a simple test > that sets up a BAR (say from hw/ivshmem.c), writes and reads to see that > it is visible, programs the bridge to filter part of the BAR out, then > writes and reads again to verify that the correct part is filtered out.
I am testing ivshmem now. But I do not know how to access the memory specified in the BAR. Thanks Wen Congyang >
