Thanks Kevin for the review. >> > > > > >> > > > > PCI BAR are aligned to the power-of-2, but the actual memory on the >> > > > > device may not. A read or write access to the physical address from >> the >> > > > > last device PFN up to the next power-of-2 aligned physical address >> > > > > results in reading ~0 and dropped writes. >> > > > > >> > > > >> > > > my question to v10 was not answered. posted again: >> > > >> > > The device FW knows and tells the VM. >> > > >> > >> > This driver reads the size info from ACPI and records it as >> > nvdev->memlength. >> >> Yes, the ACPI tables have a copy of the size. > > So the ACPI copy is mainly introduced for the use of VFIO given the > real device driver can already retrieve it from device FW? Yes, the device mem size in ACPI DSDT is kept primarily for the vfio use. >> >> > But nvdev->memlength is not exposed to the userspace. How does the >> virtual >> > FW acquires this knowledge and then report it to the VM? >> >> It isn't virtual FW, I said device FW. The device itself knows how it >> is configured and it can report details about the the memory >> space. The VM just DMA's a RPC and asks it. >> > > Interesting. Perhaps this message should be included in the commit > message to help compose a clear picture. I will add it, yes. > With that, > > Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx> Thanks!
