diff options
Diffstat (limited to 'hw/xive2.c')
| -rw-r--r-- | hw/xive2.c | 20 |
1 files changed, 18 insertions, 2 deletions
@@ -1491,6 +1491,8 @@ static bool xive_configure_bars(struct xive *x) xive_dbg(x, "NVP: %14p [0x%012llx]\n", x->nvp_base, x->nvp_size); xive_dbg(x, "ESB: %14p [0x%012llx]\n", x->esb_base, x->esb_size); xive_dbg(x, "END: %14p [0x%012llx]\n", x->end_base, x->end_size); + xive_dbg(x, "OVF: %14p [0x%012x]\n", x->q_ovf, + VC_QUEUE_COUNT * PAGE_SIZE); return true; } @@ -1897,8 +1899,22 @@ static bool xive_prealloc_tables(struct xive *x) return false; } - /* Allocate the queue overflow pages */ - x->q_ovf = local_alloc(x->chip_id, VC_QUEUE_COUNT * PAGE_SIZE, PAGE_SIZE); + /* + * The Memory Coherence Directory uses 16M "granule" to track + * shared copies of a cache line. If any cache line within the + * 16M range gets touched by someone outside of the group, the + * MCD forces accesses to any cache line within the range to + * include everyone that might have a shared copy. + */ +#define QUEUE_OVF_ALIGN (16 << 20) /* MCD granule size */ + + /* + * Allocate the queue overflow pages and use a 16M alignment + * to avoid sharing with other structures and reduce traffic + * on the PowerBus. + */ + x->q_ovf = local_alloc(x->chip_id, VC_QUEUE_COUNT * PAGE_SIZE, + QUEUE_OVF_ALIGN); if (!x->q_ovf) { xive_err(x, "Failed to allocate queue overflow\n"); return false; |