On Mon, 27 Nov 2017 16:24:08 +0100 Pierre Morel <pmo...@linux.vnet.ibm.com> wrote:
> On 27/11/2017 15:34, Cornelia Huck wrote: > > On Mon, 27 Nov 2017 12:02:55 +0100 > > Cornelia Huck <coh...@redhat.com> wrote: > > > >> On Mon, 27 Nov 2017 07:59:36 +0100 > >> Thomas Huth <th...@redhat.com> wrote: > >> > >>> On 25.11.2017 14:49, Pierre Morel wrote: > >>>> On 24/11/2017 07:19, Yi Min Zhao wrote: > >>>>> > >>>>> > >>>>> 在 2017/11/23 下午8:18, Thomas Huth 写道: > >>>>>> On 23.11.2017 13:07, Yi Min Zhao wrote: > >> > >>>>>>> Another question, does 'cpu' in cpu_to_le**() or le**_to_cpu() mean > >>>>>>> the > >>>>>>> host endianess? > >>>>>> Yes, the "cpu" in cpu_to_le or le_to_cpu means the host, indeed. It's > >>>>>> confusing :-/ > >>>>>> > >>>>>>> If the answers to upper two questions are yes, we actually need handle > >>>>>>> two cases. > >>>>>>> 1) For pcilg, we need to translate the data to little-endian, thus > >>>>>>> cpu_to_le**(). > >>>>>>> 2) For pcistg, we need to translate the data to host endianess, thus > >>>>>>> le**_to_cpu(). > >>>>>> I think we've got to byte-swap if the host is big endian (s390x), but > >>>>>> not if the host is little endian (x86 with TCG). > >>>> > >>>> Here is my comprehension of this funny swapping: > >>>> > >>>> - TCG for a BE guest and a le host swap bytes because if we do (register > >>>> & 0x01) in the zPCI interception code it must work what ever the > >>>> endianess is. > >>> > >>> Uhhh, I might have missed that the value has already been byte-swapped > >>> once by TCG for env->regs[r1] ... > >>> Now I'm pretty much completely confused ... sorry for the noise if I was > >>> wrong... I think it's best you ignore my comment for now (i.e. go with > >>> bswapXX() instead of le_to_cpuXX()), and if we later wire up zPCI with > >>> TCG, we still can fix this if necessary. > >> > >> I'll try my current pci/tcg patches on LPAR with this (or a v4) on top. > >> If it works there (it doesn't yet on my laptop), we do have a > >> endianness issue... (unfortunately, the reverse isn't true.) > > > > It does not look too bad: I can get a nice enP1p0s0 device from a > > virtio-net-pci with my tcg patches on my laptop (with these patches as > > well, of course). So, endianness is likely mostly fine. > > On the Lpar and on the Laptop or only on the Lpar ? Both :) > > > > >> > >> I'll post my pci/tcg patches once I get it mostly working (and it does > >> not look like a horror from the crypt anymore). > > > > Time to get out the make up kit for these. > > > > >
