On 08/28/2017 11:33 PM, Pranith Kumar wrote:
> + * TODO: rewrite this comment
> */
> -#define CPU_TLB_BITS \
> - MIN(8, \
> - TCG_TARGET_TLB_DISPLACEMENT_BITS - CPU_TLB_ENTRY_BITS - \
> - (NB_MMU_MODES <= 1 ? 0 : \
> - NB_MMU_MODES <= 2 ? 1 : \
> - NB_MMU_MODES <= 4 ? 2 : \
> - NB_MMU_MODES <= 8 ? 3 : 4))
> +#define CPU_TLB_BITS MIN(12, TCG_TARGET_TLB_MAX_INDEX_BITS)
>
Ah, no. This will cause several builds to fail.
You still need to restrict the *total* size of
the TLB to TCG_TARGET_TLB_DISPLACEMENT_BITS.
(That's not a 100% accurate statement, but is close.
See the QEMU_BUILD_BUG_ON in tcg/*/*.c for specifics.)
The upshot is that if a target has 2 MMU modes,
we can allow them to be bigger. But if it has 8,
we have to make them smaller.
I was expecting you to write
MIN(MIN(12, TCG_TARGET_TLB_MAX_INDEX_BITS)
TCG_TARGET_TLB_DISPLACEMENT_BITS - CPU_TLB_ENTRY_BITS -
...)
r~
