On Thu, 15 Feb 2024 14:28:14 +0000 Jonathan Cameron via <qemu-devel@nongnu.org> wrote:
Any comments? Almost all the other fixes I need for CXL memory to work as normal ram are queued up so I'd love it if we can solve this one as well. This looks like a big series, but it's really just a refactor + trivial addition - so shouldn't be too scary! Jonathan > Issue seen testing virtio-blk-pci with CXL emulated interleave memory. > Tests were done on arm64, but the issue isn't architecture specific. > Note that some additional fixes are needed to TCG to be able to run far > enough to hit this on arm64 or x86. They are issues so I'll post separate > series shortly. > > The address_space_read_cached_slow() and address_space_write_cached_slow() > functions query the MemoryRegion for the cached address space correctly > using address_space_translate_cached() but then call into > flatview_read_continue() / flatview_write_continue() > If the access is to a MMIO MemoryRegion and is bigger than the MemoryRegion > supports, the loop will query the MemoryRegion for the next access to use. > That query uses flatview_translate() but the address passed is suitable > for the cache, not the flatview. On my test setup that mean the second > 8 bytes and onwards of the virtio descriptor was read from flash memory > at the beginning of the system address map, not the CXL emulated memory > where the descriptor was found. Result happened to be all fs so easy to > spot. > > Changes these calls to use address_space_translate_cached() to get the > correct MemoryRegion for the cache. To avoid duplicating most of the > code, the first 2 patches factor out the common parts of > flatview_read_continue() and flatview_write_continue() so they can > be reused. > > Write path has not been tested but it so similar to the read path I've > included it here. > > Jonathan Cameron (3): > physmem: Reduce local variable scope in flatview_read/write_continue() > physmem: Factor out body of flatview_read/write_continue() loop > physmem: Fix wrong MR in large address_space_read/write_cached_slow() > > system/physmem.c | 245 ++++++++++++++++++++++++++++++++--------------- > 1 file changed, 170 insertions(+), 75 deletions(-) >
