On Tue, Sep 1, 2015 at 9:28 AM, Jan Kiszka <jan.kiszka@xxxxxxxxxxx> wrote: > On 2015-09-01 18:02, Michael S. Tsirkin wrote: ... >> You don't need to be able to map all guest memory if you know >> guest won't try to allow device access to all of it. >> It's a question of how good is the bus address allocator. > > But those BARs need to allocate a guest-physical address range as large > as the other guest's RAM is, possibly even larger if that RAM is not > contiguous, and you can't put other resources into potential holes > because VM2 does not know where those holes will be. > I think you can allocate such guest-physical address ranges efficiently if each BAR sets the base of each memory region reported by VHOST_SET_MEM_TABLE, for example. The issue is that we would need to 8 (VHOST_MEMORY_MAX_NREGIONS) of them vs. 6 (defined by PCI-SIG). -- Jun Intel Open Source Technology Center _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
