@@ -25,7 +25,6 @@
#include <drm/drm_print.h>
#include "i915_drv.h"
-#include "i915_vgpu.h"
#include "intel_ringbuffer.h"
#include "intel_lrc.h"
@@ -456,21 +455,10 @@ static void intel_engine_init_batch_pool(struct intel_engine_cs *engine)
i915_gem_batch_pool_init(&engine->batch_pool, engine);
}
-static bool csb_force_mmio(struct drm_i915_private *i915)
-{
- /* Older GVT emulation depends upon intercepting CSB mmio */
- if (intel_vgpu_active(i915) && !intel_vgpu_has_hwsp_emulation(i915))
- return true;
-
- return false;
-}
-
static void intel_engine_init_execlist(struct intel_engine_cs *engine)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
- execlists->csb_use_mmio = csb_force_mmio(engine->i915);
-
execlists->port_mask = 1;
BUILD_BUG_ON_NOT_POWER_OF_2(execlists_num_ports(execlists));
GEM_BUG_ON(execlists_num_ports(execlists) > EXECLIST_MAX_PORTS);
@@ -137,6 +137,7 @@
#include <drm/i915_drm.h>
#include "i915_drv.h"
#include "i915_gem_render_state.h"
+#include "i915_vgpu.h"
#include "intel_lrc_reg.h"
#include "intel_mocs.h"
#include "intel_workarounds.h"
@@ -953,44 +954,40 @@ static void process_csb(struct intel_engine_cs *engine)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
struct execlist_port *port = execlists->port;
- struct drm_i915_private *i915 = engine->i915;
-
- /* The HWSP contains a (cacheable) mirror of the CSB */
- const u32 *buf =
- &engine->status_page.page_addr[I915_HWS_CSB_BUF0_INDEX];
- unsigned int head, tail;
- bool fw = false;
+ const u32 * const buf = execlists->csb_status;
+ u8 head, tail;
/* Clear before reading to catch new interrupts */
clear_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted);
smp_mb__after_atomic();
- if (unlikely(execlists->csb_use_mmio)) {
- intel_uncore_forcewake_get(i915, execlists->fw_domains);
- fw = true;
-
- buf = (u32 * __force)
- (i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_BUF_LO(engine, 0)));
-
- head = readl(i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine)));
- tail = GEN8_CSB_WRITE_PTR(head);
- head = GEN8_CSB_READ_PTR(head);
- execlists->csb_head = head;
- } else {
- const int write_idx =
- intel_hws_csb_write_index(i915) -
- I915_HWS_CSB_BUF0_INDEX;
+ /*
+ * Note that csb_write, csb_status may be either in HWSP or mmio.
+ * When reading from the csb_write mmio register, we have to be
+ * careful to only use the GEN8_CSB_WRITE_PTR portion, which is
+ * the low 4bits. As it happens we know the next 4bits are always
+ * zero and so we can simply masked off the low u8 of the register
+ * and treat it identically to reading from the HWSP (without having
+ * to use explicit shifting and masking, and probably bifurcating
+ * the code to handle the legacy mmio read).
+ */
+ head = execlists->csb_head;
+ tail = READ_ONCE(*execlists->csb_write);
+ GEM_TRACE("%s cs-irq head=%d, tail=%d\n", engine->name, head, tail);
+ if (unlikely(head == tail))
+ return;
- head = execlists->csb_head;
- tail = READ_ONCE(buf[write_idx]);
- rmb(); /* Hopefully paired with a wmb() in HW */
- }
- GEM_TRACE("%s cs-irq head=%d [%d%s], tail=%d [%d%s]\n",
- engine->name,
- head, GEN8_CSB_READ_PTR(readl(i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine)))), fw ? "" : "?",
- tail, GEN8_CSB_WRITE_PTR(readl(i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine)))), fw ? "" : "?");
+ /*
+ * Hopefully paired with a wmb() in HW!
+ *
+ * We must complete the read of the write pointer before any reads
+ * from the CSB, so that we do not see stale values. Without an rmb
+ * (lfence) the HW may speculatively perform the CSB[] reads *before*
+ * we perform the READ_ONCE(*csb_write).
+ */
+ rmb();
- while (head != tail) {
+ do {
struct i915_request *rq;
unsigned int status;
unsigned int count;
@@ -1016,12 +1013,12 @@ static void process_csb(struct intel_engine_cs *engine)
* status notifier.
*/
- status = READ_ONCE(buf[2 * head]); /* maybe mmio! */
GEM_TRACE("%s csb[%d]: status=0x%08x:0x%08x, active=0x%x\n",
engine->name, head,
- status, buf[2*head + 1],
+ buf[2 * head + 0], buf[2 * head + 1],
execlists->active);
+ status = buf[2 * head];
if (status & (GEN8_CTX_STATUS_IDLE_ACTIVE |
GEN8_CTX_STATUS_PREEMPTED))
execlists_set_active(execlists,
@@ -1103,16 +1100,11 @@ static void process_csb(struct intel_engine_cs *engine)
} else {
port_set(port, port_pack(rq, count));
}
- }
-
- if (head != execlists->csb_head) {
- execlists->csb_head = head;
- writel(_MASKED_FIELD(GEN8_CSB_READ_PTR_MASK, head << 8),
- i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine)));
- }
+ } while (head != tail);
- if (unlikely(fw))
- intel_uncore_forcewake_put(i915, execlists->fw_domains);
+ writel(_MASKED_FIELD(GEN8_CSB_READ_PTR_MASK, head << 8),
+ execlists->csb_read);
+ execlists->csb_head = head;
}
/*
@@ -2430,28 +2422,11 @@ logical_ring_default_irqs(struct intel_engine_cs *engine)
static void
logical_ring_setup(struct intel_engine_cs *engine)
{
- struct drm_i915_private *dev_priv = engine->i915;
- enum forcewake_domains fw_domains;
-
intel_engine_setup_common(engine);
/* Intentionally left blank. */
engine->buffer = NULL;
- fw_domains = intel_uncore_forcewake_for_reg(dev_priv,
- RING_ELSP(engine),
- FW_REG_WRITE);
-
- fw_domains |= intel_uncore_forcewake_for_reg(dev_priv,
- RING_CONTEXT_STATUS_PTR(engine),
- FW_REG_READ | FW_REG_WRITE);
-
- fw_domains |= intel_uncore_forcewake_for_reg(dev_priv,
- RING_CONTEXT_STATUS_BUF_BASE(engine),
- FW_REG_READ);
-
- engine->execlists.fw_domains = fw_domains;
-
tasklet_init(&engine->execlists.tasklet,
execlists_submission_tasklet, (unsigned long)engine);
@@ -2459,34 +2434,56 @@ logical_ring_setup(struct intel_engine_cs *engine)
logical_ring_default_irqs(engine);
}
+static bool csb_force_mmio(struct drm_i915_private *i915)
+{
+ /* Older GVT emulation depends upon intercepting CSB mmio */
+ return intel_vgpu_active(i915) && !intel_vgpu_has_hwsp_emulation(i915);
+}
+
static int logical_ring_init(struct intel_engine_cs *engine)
{
+ struct drm_i915_private *i915 = engine->i915;
+ struct intel_engine_execlists * const execlists = &engine->execlists;
int ret;
ret = intel_engine_init_common(engine);
if (ret)
goto error;
- if (HAS_LOGICAL_RING_ELSQ(engine->i915)) {
- engine->execlists.submit_reg = engine->i915->regs +
+ if (HAS_LOGICAL_RING_ELSQ(i915)) {
+ execlists->submit_reg = i915->regs +
i915_mmio_reg_offset(RING_EXECLIST_SQ_CONTENTS(engine));
- engine->execlists.ctrl_reg = engine->i915->regs +
+ execlists->ctrl_reg = i915->regs +
i915_mmio_reg_offset(RING_EXECLIST_CONTROL(engine));
} else {
- engine->execlists.submit_reg = engine->i915->regs +
+ execlists->submit_reg = i915->regs +
i915_mmio_reg_offset(RING_ELSP(engine));
}
- engine->execlists.preempt_complete_status = ~0u;
- if (engine->i915->preempt_context) {
+ execlists->preempt_complete_status = ~0u;
+ if (i915->preempt_context) {
struct intel_context *ce =
- to_intel_context(engine->i915->preempt_context, engine);
+ to_intel_context(i915->preempt_context, engine);
- engine->execlists.preempt_complete_status =
+ execlists->preempt_complete_status =
upper_32_bits(ce->lrc_desc);
}
- engine->execlists.csb_head = GEN8_CSB_ENTRIES - 1;
+ execlists->csb_head = GEN8_CSB_ENTRIES - 1;
+ execlists->csb_read =
+ i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine));
+ if (csb_force_mmio(i915)) {
+ execlists->csb_status = (u32 __force *)
+ (i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_BUF_LO(engine, 0)));
+
+ execlists->csb_write = (u32 __force *)execlists->csb_read;
+ } else {
+ execlists->csb_status =
+ &engine->status_page.page_addr[I915_HWS_CSB_BUF0_INDEX];
+
+ execlists->csb_write =
+ &engine->status_page.page_addr[intel_hws_csb_write_index(i915)];
+ }
return 0;
@@ -300,24 +300,35 @@ struct intel_engine_execlists {
struct rb_node *first;
/**
- * @fw_domains: forcewake domains for irq tasklet
+ * @csb_read: control register for Context Switch buffer
+ *
+ * Note this register is always in mmio.
*/
- unsigned int fw_domains;
+ u32 __iomem *csb_read;
/**
- * @csb_head: context status buffer head
+ * @csb_write: control register for Context Switch buffer
+ *
+ * Note this register may be either mmio or HWSP shadow.
*/
- unsigned int csb_head;
+ u32 *csb_write;
/**
- * @csb_use_mmio: access csb through mmio, instead of hwsp
+ * @csb_status: status array for Context Switch buffer
+ *
+ * Note these register may be either mmio or HWSP shadow.
*/
- bool csb_use_mmio;
+ u32 *csb_status;
/**
* @preempt_complete_status: expected CSB upon completing preemption
*/
u32 preempt_complete_status;
+
+ /**
+ * @csb_head: context status buffer head
+ */
+ u8 csb_head;
};
#define INTEL_ENGINE_CS_MAX_NAME 8