17a0364cb0
H_PUT_TCE_INDIRECT allows packing up to 512 TCE updates into a single hypercall; H_STUFF_TCE can clear lots in a single hypercall too. However, unlike H_STUFF_TCE (which writes the same TCE to all entries), H_PUT_TCE_INDIRECT uses a 4K page with new TCEs. In a secure VM environment this means sharing a secure VM page with a hypervisor which we would rather avoid. This splits the FW_FEATURE_MULTITCE feature into FW_FEATURE_PUT_TCE_IND and FW_FEATURE_STUFF_TCE. "hcall-multi-tce" in the "/rtas/ibm,hypertas-functions" device tree property sets both; the "multitce=off" kernel command line parameter disables both. This should not cause behavioural change. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> Tested-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20191216041924.42318-4-aik@ozlabs.ru
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.