diff options
| -rw-r--r-- | hw/intc/xive.c | 96 |
1 files changed, 95 insertions, 1 deletions
diff --git a/hw/intc/xive.c b/hw/intc/xive.c index 1d737346c3..607e74acd2 100644 --- a/hw/intc/xive.c +++ b/hw/intc/xive.c @@ -22,9 +22,75 @@ * XIVE Thread Interrupt Management context */ +/* + * Convert a priority number to an Interrupt Pending Buffer (IPB) + * register, which indicates a pending interrupt at the priority + * corresponding to the bit number + */ +static uint8_t priority_to_ipb(uint8_t priority) +{ + return priority > XIVE_PRIORITY_MAX ? + 0 : 1 << (XIVE_PRIORITY_MAX - priority); +} + +/* + * Convert an Interrupt Pending Buffer (IPB) register to a Pending + * Interrupt Priority Register (PIPR), which contains the priority of + * the most favored pending notification. + */ +static uint8_t ipb_to_pipr(uint8_t ibp) +{ + return ibp ? clz32((uint32_t)ibp << 24) : 0xff; +} + +static void ipb_update(uint8_t *regs, uint8_t priority) +{ + regs[TM_IPB] |= priority_to_ipb(priority); + regs[TM_PIPR] = ipb_to_pipr(regs[TM_IPB]); +} + +static uint8_t exception_mask(uint8_t ring) +{ + switch (ring) { + case TM_QW1_OS: + return TM_QW1_NSR_EO; + default: + g_assert_not_reached(); + } +} + static uint64_t xive_tctx_accept(XiveTCTX *tctx, uint8_t ring) { - return 0; + uint8_t *regs = &tctx->regs[ring]; + uint8_t nsr = regs[TM_NSR]; + uint8_t mask = exception_mask(ring); + + qemu_irq_lower(tctx->output); + + if (regs[TM_NSR] & mask) { + uint8_t cppr = regs[TM_PIPR]; + + regs[TM_CPPR] = cppr; + + /* Reset the pending buffer bit */ + regs[TM_IPB] &= ~priority_to_ipb(cppr); + regs[TM_PIPR] = ipb_to_pipr(regs[TM_IPB]); + + /* Drop Exception bit */ + regs[TM_NSR] &= ~mask; + } + + return (nsr << 8) | regs[TM_CPPR]; +} + +static void xive_tctx_notify(XiveTCTX *tctx, uint8_t ring) +{ + uint8_t *regs = &tctx->regs[ring]; + + if (regs[TM_PIPR] < regs[TM_CPPR]) { + regs[TM_NSR] |= exception_mask(ring); + qemu_irq_raise(tctx->output); + } } static void xive_tctx_set_cppr(XiveTCTX *tctx, uint8_t ring, uint8_t cppr) @@ -34,6 +100,9 @@ static void xive_tctx_set_cppr(XiveTCTX *tctx, uint8_t ring, uint8_t cppr) } tctx->regs[ring + TM_CPPR] = cppr; + + /* CPPR has changed, check if we need to raise a pending exception */ + xive_tctx_notify(tctx, ring); } /* @@ -190,6 +259,17 @@ static void xive_tm_set_os_cppr(XiveTCTX *tctx, hwaddr offset, } /* + * Adjust the IPB to allow a CPU to process event queues of other + * priorities during one physical interrupt cycle. + */ +static void xive_tm_set_os_pending(XiveTCTX *tctx, hwaddr offset, + uint64_t value, unsigned size) +{ + ipb_update(&tctx->regs[TM_QW1_OS], value & 0xff); + xive_tctx_notify(tctx, TM_QW1_OS); +} + +/* * Define a mapping of "special" operations depending on the TIMA page * offset and the size of the operation. */ @@ -211,6 +291,7 @@ static const XiveTmOp xive_tm_operations[] = { /* MMIOs above 2K : special operations with side effects */ { XIVE_TM_OS_PAGE, TM_SPC_ACK_OS_REG, 2, NULL, xive_tm_ack_os_reg }, + { XIVE_TM_OS_PAGE, TM_SPC_SET_OS_PENDING, 1, xive_tm_set_os_pending, NULL }, }; static const XiveTmOp *xive_tm_find_op(hwaddr offset, unsigned size, bool write) @@ -373,6 +454,13 @@ static void xive_tctx_reset(void *dev) tctx->regs[TM_QW1_OS + TM_LSMFB] = 0xFF; tctx->regs[TM_QW1_OS + TM_ACK_CNT] = 0xFF; tctx->regs[TM_QW1_OS + TM_AGE] = 0xFF; + + /* + * Initialize PIPR to 0xFF to avoid phantom interrupts when the + * CPPR is first set. + */ + tctx->regs[TM_QW1_OS + TM_PIPR] = + ipb_to_pipr(tctx->regs[TM_QW1_OS + TM_IPB]); } static void xive_tctx_realize(DeviceState *dev, Error **errp) @@ -1155,9 +1243,15 @@ static void xive_presenter_notify(XiveRouter *xrtr, uint8_t format, found = xive_presenter_match(xrtr, format, nvt_blk, nvt_idx, cam_ignore, priority, logic_serv, &match); if (found) { + ipb_update(&match.tctx->regs[match.ring], priority); + xive_tctx_notify(match.tctx, match.ring); return; } + /* Record the IPB in the associated NVT structure */ + ipb_update((uint8_t *) &nvt.w4, priority); + xive_router_write_nvt(xrtr, nvt_blk, nvt_idx, &nvt, 4); + /* * If no matching NVT is dispatched on a HW thread : * - update the NVT structure if backlog is activated |