Re: [PATCH 01/13] hw/intc/arm_gicv3_its: Use address_space_map() to access command queue packets

[Richard Henderson <richard.henderson@linaro.org>]

On 2/2/22 06:31, Peter Maydell wrote:
> Currently the ITS accesses each 8-byte doubleword in a 4-doubleword
> command packet with a separate address_space_ldq_le() call.  This is
> awkward because the individual command processing functions have
> ended up with code to handle "load more doublewords out of the
> packet", which is both unwieldy and also a potential source of bugs
> because it's not obvious when looking at a line that pulls a field
> out of the 'value' variable which of the 4 doublewords that variable
> currently holds.
> 
> Switch to using address_space_map() to map the whole command packet
> at once and fish the four doublewords out of it.  Then each process_*
> function can start with a few lines of code that extract the fields
> it cares about.
> 
> This requires us to split out the guts of process_its_cmd() into a
> new do_process_its_cmd(), because we were previously overloading the
> value and offset arguments as a backdoor way to directly pass the
> devid and eventid from a write to GITS_TRANSLATER.  The new
> do_process_its_cmd() takes those arguments directly, and
> process_its_cmd() is just a wrapper that does the "read fields from
> command packet" part.
> 
> Signed-off-by: Peter Maydell<peter.maydell@linaro.org>
> ---
>   hw/intc/gicv3_internal.h |   4 +-
>   hw/intc/arm_gicv3_its.c  | 208 +++++++++++----------------------------
>   2 files changed, 62 insertions(+), 150 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~