hw/intc/arm_gicv3_cpuif: Support vLPIs

The CPU interface changes to support vLPIs are fairly minor:
in the parts of the code that currently look at the list registers
to determine the highest priority pending virtual interrupt, we
must also look at the highest priority pending vLPI. To do this
we change hppvi_index() to check the vLPI and return a special-case
value if that is the right virtual interrupt to take. The callsites
(which handle HPPIR and IAR registers and the "raise vIRQ and vFIQ
lines" code) then have to handle this special-case value.

This commit includes two interfaces with the as-yet-unwritten
redistributor code:
 * the new GICv3CPUState::hppvlpi will be set by the redistributor
   (in the same way as the existing hpplpi does for physical LPIs)
 * when the CPU interface acknowledges a vLPI it needs to set it
   to non-pending; the new gicv3_redist_vlpi_pending() function
   (which matches the existing gicv3_redist_lpi_pending() used
   for physical LPIs) is a stub that will be filled in later

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220408141550.1271295-26-peter.maydell@linaro.org

diff --git a/hw/intc/arm_gicv3_common.c b/hw/intc/arm_gicv3_common.c
index 14d76d748407f49ebf9cf2daf45af0e4728aa316..3f47b3501fe6737b5125134f606ce89b3f10c4ad 100644 (file)
--- a/hw/intc/arm_gicv3_common.c
+++ b/hw/intc/arm_gicv3_common.c
@@ -487,6 +487,7 @@ static void arm_gicv3_common_reset(DeviceState *dev)
 
         cs->hppi.prio = 0xff;
         cs->hpplpi.prio = 0xff;
+        cs->hppvlpi.prio = 0xff;
 
         /* State in the CPU interface must *not* be reset here, because it
          * is part of the CPU's reset domain, not the GIC device's.

diff --git a/hw/intc/arm_gicv3_cpuif.c b/hw/intc/arm_gicv3_cpuif.c
index 5fb64d4663c6563fc4e78c463661bfd214570d67..f11863ff613b821ff14638751e94dc8644decf64 100644 (file)
--- a/hw/intc/arm_gicv3_cpuif.c
+++ b/hw/intc/arm_gicv3_cpuif.c
@@ -21,6 +21,12 @@
 #include "hw/irq.h"
 #include "cpu.h"
 
+/*
+ * Special case return value from hppvi_index(); must be larger than
+ * the architecturally maximum possible list register index (which is 15)
+ */
+#define HPPVI_INDEX_VLPI 16
+
 static GICv3CPUState *icc_cs_from_env(CPUARMState *env)
 {
     return env->gicv3state;
@@ -157,10 +163,18 @@ static int ich_highest_active_virt_prio(GICv3CPUState *cs)
 
 static int hppvi_index(GICv3CPUState *cs)
 {
-    /* Return the list register index of the highest priority pending
+    /*
+     * Return the list register index of the highest priority pending
      * virtual interrupt, as per the HighestPriorityVirtualInterrupt
      * pseudocode. If no pending virtual interrupts, return -1.
+     * If the highest priority pending virtual interrupt is a vLPI,
+     * return HPPVI_INDEX_VLPI.
+     * (The pseudocode handles checking whether the vLPI is higher
+     * priority than the highest priority list register at every
+     * callsite of HighestPriorityVirtualInterrupt; we check it here.)
      */
+    ARMCPU *cpu = ARM_CPU(cs->cpu);
+    CPUARMState *env = &cpu->env;
     int idx = -1;
     int i;
     /* Note that a list register entry with a priority of 0xff will
@@ -202,6 +216,23 @@ static int hppvi_index(GICv3CPUState *cs)
         }
     }
 
+    /*
+     * "no pending vLPI" is indicated with prio = 0xff, which always
+     * fails the priority check here. vLPIs are only considered
+     * when we are in Non-Secure state.
+     */
+    if (cs->hppvlpi.prio < prio && !arm_is_secure(env)) {
+        if (cs->hppvlpi.grp == GICV3_G0) {
+            if (cs->ich_vmcr_el2 & ICH_VMCR_EL2_VENG0) {
+                return HPPVI_INDEX_VLPI;
+            }
+        } else {
+            if (cs->ich_vmcr_el2 & ICH_VMCR_EL2_VENG1) {
+                return HPPVI_INDEX_VLPI;
+            }
+        }
+    }
+
     return idx;
 }
 
@@ -289,6 +320,47 @@ static bool icv_hppi_can_preempt(GICv3CPUState *cs, uint64_t lr)
     return false;
 }
 
+static bool icv_hppvlpi_can_preempt(GICv3CPUState *cs)
+{
+    /*
+     * Return true if we can signal the highest priority pending vLPI.
+     * We can assume we're Non-secure because hppvi_index() already
+     * tested for that.
+     */
+    uint32_t mask, rprio, vpmr;
+
+    if (!(cs->ich_hcr_el2 & ICH_HCR_EL2_EN)) {
+        /* Virtual interface disabled */
+        return false;
+    }
+
+    vpmr = extract64(cs->ich_vmcr_el2, ICH_VMCR_EL2_VPMR_SHIFT,
+                     ICH_VMCR_EL2_VPMR_LENGTH);
+
+    if (cs->hppvlpi.prio >= vpmr) {
+        /* Priority mask masks this interrupt */
+        return false;
+    }
+
+    rprio = ich_highest_active_virt_prio(cs);
+    if (rprio == 0xff) {
+        /* No running interrupt so we can preempt */
+        return true;
+    }
+
+    mask = icv_gprio_mask(cs, cs->hppvlpi.grp);
+
+    /*
+     * We only preempt a running interrupt if the pending interrupt's
+     * group priority is sufficient (the subpriorities are not considered).
+     */
+    if ((cs->hppvlpi.prio & mask) < (rprio & mask)) {
+        return true;
+    }
+
+    return false;
+}
+
 static uint32_t eoi_maintenance_interrupt_state(GICv3CPUState *cs,
                                                 uint32_t *misr)
 {
@@ -386,8 +458,18 @@ void gicv3_cpuif_virt_irq_fiq_update(GICv3CPUState *cs)
     int fiqlevel = 0;
 
     idx = hppvi_index(cs);
-    trace_gicv3_cpuif_virt_update(gicv3_redist_affid(cs), idx);
-    if (idx >= 0) {
+    trace_gicv3_cpuif_virt_update(gicv3_redist_affid(cs), idx,
+                                  cs->hppvlpi.irq, cs->hppvlpi.grp,
+                                  cs->hppvlpi.prio);
+    if (idx == HPPVI_INDEX_VLPI) {
+        if (icv_hppvlpi_can_preempt(cs)) {
+            if (cs->hppvlpi.grp == GICV3_G0) {
+                fiqlevel = 1;
+            } else {
+                irqlevel = 1;
+            }
+        }
+    } else if (idx >= 0) {
         uint64_t lr = cs->ich_lr_el2[idx];
 
         if (icv_hppi_can_preempt(cs, lr)) {
@@ -619,7 +701,11 @@ static uint64_t icv_hppir_read(CPUARMState *env, const ARMCPRegInfo *ri)
     int idx = hppvi_index(cs);
     uint64_t value = INTID_SPURIOUS;
 
-    if (idx >= 0) {
+    if (idx == HPPVI_INDEX_VLPI) {
+        if (cs->hppvlpi.grp == grp) {
+            value = cs->hppvlpi.irq;
+        }
+    } else if (idx >= 0) {
         uint64_t lr = cs->ich_lr_el2[idx];
         int thisgrp = (lr & ICH_LR_EL2_GROUP) ? GICV3_G1NS : GICV3_G0;
 
@@ -650,6 +736,18 @@ static void icv_activate_irq(GICv3CPUState *cs, int idx, int grp)
     cs->ich_apr[grp][regno] |= (1 << regbit);
 }
 
+static void icv_activate_vlpi(GICv3CPUState *cs)
+{
+    uint32_t mask = icv_gprio_mask(cs, cs->hppvlpi.grp);
+    int prio = cs->hppvlpi.prio & mask;
+    int aprbit = prio >> (8 - cs->vprebits);
+    int regno = aprbit / 32;
+    int regbit = aprbit % 32;
+
+    cs->ich_apr[cs->hppvlpi.grp][regno] |= (1 << regbit);
+    gicv3_redist_vlpi_pending(cs, cs->hppvlpi.irq, 0);
+}
+
 static uint64_t icv_iar_read(CPUARMState *env, const ARMCPRegInfo *ri)
 {
     GICv3CPUState *cs = icc_cs_from_env(env);
@@ -657,7 +755,12 @@ static uint64_t icv_iar_read(CPUARMState *env, const ARMCPRegInfo *ri)
     int idx = hppvi_index(cs);
     uint64_t intid = INTID_SPURIOUS;
 
-    if (idx >= 0) {
+    if (idx == HPPVI_INDEX_VLPI) {
+        if (cs->hppvlpi.grp == grp && icv_hppvlpi_can_preempt(cs)) {
+            intid = cs->hppvlpi.irq;
+            icv_activate_vlpi(cs);
+        }
+    } else if (idx >= 0) {
         uint64_t lr = cs->ich_lr_el2[idx];
         int thisgrp = (lr & ICH_LR_EL2_GROUP) ? GICV3_G1NS : GICV3_G0;
 
@@ -2632,6 +2735,12 @@ static void gicv3_cpuif_el_change_hook(ARMCPU *cpu, void *opaque)
     GICv3CPUState *cs = opaque;
 
     gicv3_cpuif_update(cs);
+    /*
+     * Because vLPIs are only pending in NonSecure state,
+     * an EL change can change the VIRQ/VFIQ status (but
+     * cannot affect the maintenance interrupt state)
+     */
+    gicv3_cpuif_virt_irq_fiq_update(cs);
 }
 
 void gicv3_init_cpuif(GICv3State *s)

diff --git a/hw/intc/arm_gicv3_redist.c b/hw/intc/arm_gicv3_redist.c
index c310d7f8ff279825f96bf6f8bb52dfedb3ce5031..3464972c1399ae0a48b4b5b969a2529ee36e9755 100644 (file)
--- a/hw/intc/arm_gicv3_redist.c
+++ b/hw/intc/arm_gicv3_redist.c
@@ -855,6 +855,14 @@ void gicv3_redist_movall_lpis(GICv3CPUState *src, GICv3CPUState *dest)
     gicv3_redist_update_lpi(dest);
 }
 
+void gicv3_redist_vlpi_pending(GICv3CPUState *cs, int irq, int level)
+{
+    /*
+     * The redistributor handling for changing the pending state
+     * of a vLPI will be added in a subsequent commit.
+     */
+}
+
 void gicv3_redist_process_vlpi(GICv3CPUState *cs, int irq, uint64_t vptaddr,
                                int doorbell, int level)
 {

diff --git a/hw/intc/gicv3_internal.h b/hw/intc/gicv3_internal.h
index 052aa96c772519aaa9502127850141dda7e2692d..2a9d3cf974d1d23ea5376198ffb020fea4e4a9d7 100644 (file)
--- a/hw/intc/gicv3_internal.h
+++ b/hw/intc/gicv3_internal.h
@@ -612,6 +612,19 @@ void gicv3_redist_process_lpi(GICv3CPUState *cs, int irq, int level);
  */
 void gicv3_redist_process_vlpi(GICv3CPUState *cs, int irq, uint64_t vptaddr,
                                int doorbell, int level);
+/**
+ * gicv3_redist_vlpi_pending:
+ * @cs: GICv3CPUState
+ * @irq: (virtual) interrupt number
+ * @level: level to set @irq to
+ *
+ * Set/clear the pending status of a virtual LPI in the vLPI table
+ * that this redistributor is currently using. (The difference between
+ * this and gicv3_redist_process_vlpi() is that this is called from
+ * the cpuif and does not need to do the not-running-on-this-vcpu checks.)
+ */
+void gicv3_redist_vlpi_pending(GICv3CPUState *cs, int irq, int level);
+
 void gicv3_redist_lpi_pending(GICv3CPUState *cs, int irq, int level);
 /**
  * gicv3_redist_update_lpi:

diff --git a/hw/intc/trace-events b/hw/intc/trace-events
index 36c3fe4da0bad92af910db37ad8629faef8662e1..5271590304b491f6f0115eb19b4562c9e76179d3 100644 (file)
--- a/hw/intc/trace-events
+++ b/hw/intc/trace-events
@@ -151,7 +151,7 @@ gicv3_icv_hppir_read(int grp, uint32_t cpu, uint64_t val) "GICv3 ICV_HPPIR%d rea
 gicv3_icv_dir_write(uint32_t cpu, uint64_t val) "GICv3 ICV_DIR write cpu 0x%x value 0x%" PRIx64
 gicv3_icv_iar_read(int grp, uint32_t cpu, uint64_t val) "GICv3 ICV_IAR%d read cpu 0x%x value 0x%" PRIx64
 gicv3_icv_eoir_write(int grp, uint32_t cpu, uint64_t val) "GICv3 ICV_EOIR%d write cpu 0x%x value 0x%" PRIx64
-gicv3_cpuif_virt_update(uint32_t cpuid, int idx) "GICv3 CPU i/f 0x%x virt HPPI update LR index %d"
+gicv3_cpuif_virt_update(uint32_t cpuid, int idx, int hppvlpi, int grp, int prio) "GICv3 CPU i/f 0x%x virt HPPI update LR index %d HPPVLPI %d grp %d prio %d"
 gicv3_cpuif_virt_set_irqs(uint32_t cpuid, int fiqlevel, int irqlevel) "GICv3 CPU i/f 0x%x virt HPPI update: setting FIQ %d IRQ %d"
 gicv3_cpuif_virt_set_maint_irq(uint32_t cpuid, int maintlevel) "GICv3 CPU i/f 0x%x virt HPPI update: setting maintenance-irq %d"
 

diff --git a/include/hw/intc/arm_gicv3_common.h b/include/hw/intc/arm_gicv3_common.h
index 7ff5a1aa5fce84cc8f2aa5aaf6f86c6a430c8991..4e416100559c6fd68605068cbd552e1c46894536 100644 (file)
--- a/include/hw/intc/arm_gicv3_common.h
+++ b/include/hw/intc/arm_gicv3_common.h
@@ -219,6 +219,9 @@ struct GICv3CPUState {
      */
     PendingIrq hpplpi;
 
+    /* Cached information recalculated from vLPI tables in guest memory */
+    PendingIrq hppvlpi;
+
     /* This is temporary working state, to avoid a malloc in gicv3_update() */
     bool seenbetter;
 };