This patch series contains the re-architected changes to kernel and userspace libraries required to provide support for the DAPL API on s390x platform. Those patches are are a prototype of proposed changes. It is not requested to include this version of changes into kernel source code and the patches are posted only to receive comments from the community on this changes concept. The current implementation of Infiniband verbs uses mapped memory areas to directly access the device UAR and Blueflame pages, which are located in the PCI I/O memory, from userspace. On the s390x platform the PCI I/O memory can be accessed only using special privileged CPU instructions that cannot be used directly in user space programs. This restricts the usage of mapped memory areas to access the PCI I/O memory on s390x platform. In the previous attempt of DAPL support on s390x platform implementation a new Infinband verb command was introduced and the changes to kernel modules and user space libraries were provided but that version of changes was rejected by community. The new version of changes introduces new kernel system calls which allow to execute the privileged CPU instructions in kernel space on request from user space programs. One system call allows the user space programs to write data to a PCI I/O memory page and the second one can be used to read data from PCI I/O memory to userspace program buffer using mapped memory area addresses as arguments. This approach of the DAPL API support on s390x platform has the following advantages: * the current Infiniband and mlx4 support modules remain unchanged; * the changes are separated into the special kernel platform specific directory; * no conditional compilation directives are used in the kernel source code; * no changes required to the kernel virtual memory management; * only minor changes are required in the user space DAPL API components. The only disadvantage of this approach is that it is still necessary to modify existing userspace library libmlx4 to replace the direct access to mapped memory areas intended for the PCI I/O memory access with the appropriate new system call invocation. The changes to the other user space DAPL component code are required only to provide the support of the s390x platform. There are 1 patch for the Linux kernel and 4 patches for the DAPL API user space components. [PATCH 1/5] s390/kernel: add system calls for access PCI memory This patch contains the new system call implementation required for the PCI I/O memory access from userspace programs on s390x platform. [PATCH 2/5] libibverbs: add support for the s390x plaform This patch contains the changes to the libibverbs user space library to provide support of the s390x platform. [PATCH 3/5] libmlx4: add support for the s390x platform This patch contains the changes to the libmlx4 user space library intended to provide the PCI I/O memory access on the s390x platform. The direct access to mapped memory areas is replaced by appropriate system call invocation. [PATCH 4/5] dapl: add support for the s390x platform This patch contains the code which is needed to be added to dapl package to allow the dapl libraries to be used on s390x platform. There is no changes added to this patch since the previous post and it is included only for refrence. [PATCH 5/5] perftest: add support for the s390x platform This patch contains the code which is neeed to be added to the perftest package applications to allow their execution on the s390x platform. There is no changes in this patch since the previous post and it is included only for refrence. Alexey Ishchuk (5): s390/kernel: add system calls for access PCI memory libibverbs: add support for s390x platform libmlx4: add support for s390x platform dapl: add support for s390x platform perftest: add support for s390x platform -- 1.8.5.5 -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
