On Wed, Aug 23, 2023 at 02:18:52PM +0000, Ankit Agrawal wrote: > >> + > >> + /* > >> + * Handle read on the BAR2 region. Map to the target device memory > >> + * physical address and copy to the request read buffer. > >> + */ > >> + if (copy_to_user(buf, (u8 *)addr + offset, read_count)) > >> + return -EFAULT; > > > > Just to verify, does this memory allow access of arbitrary alignment > > and size? > > Please correct me if I'm wrong, but based on following gdb dump data on > the corresponding MemoryRegion->ops, unaligned access isn't supported, and > a read of size upto 8 may be done. Regardless, you used MEMREMAP_WB which is equivalent to normal system memory. It supports all accesses, including atomics, and doesn't require __iomem accessors. Jason
