[Qemu-devel] [RFC v2 2/3] intc/arm_gic: Support IRQ injection for more than 256 vpus

[Eric Auger]

Host kernels that expose the KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 capability
allow injection of interrupts along with vcpu ids larger than 255.
Let's encode the vpcu id on 12 bits according to the upgraded KVM_IRQ_LINE
ABI when needed.

Given that we have two callsites that need to assemble
the value for kvm_set_irq(), a new helper routine, kvm_arm_set_irq
is introduced.

Without that patch qemu exits with "kvm_set_irq: Invalid argument"
message.

Signed-off-by: Eric Auger <address@hidden>
Reported-by: Zenghui Yu <address@hidden>
---
 hw/intc/arm_gic_kvm.c |  7 ++-----
 target/arm/cpu.c      | 10 ++++------
 target/arm/kvm.c      | 16 ++++++++++++++++
 target/arm/kvm_arm.h  |  1 +
 4 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/hw/intc/arm_gic_kvm.c b/hw/intc/arm_gic_kvm.c
index b56fda144f..9deb15e7e6 100644
--- a/hw/intc/arm_gic_kvm.c
+++ b/hw/intc/arm_gic_kvm.c
@@ -55,7 +55,7 @@ void kvm_arm_gic_set_irq(uint32_t num_irq, int irq, int level)
      * has separate fields in the irq number for type,
      * CPU number and interrupt number.
      */
-    int kvm_irq, irqtype, cpu;
+    int irqtype, cpu;
 
     if (irq < (num_irq - GIC_INTERNAL)) {
         /* External interrupt. The kernel numbers these like the GIC
@@ -72,10 +72,7 @@ void kvm_arm_gic_set_irq(uint32_t num_irq, int irq, int 
level)
         cpu = irq / GIC_INTERNAL;
         irq %= GIC_INTERNAL;
     }
-    kvm_irq = (irqtype << KVM_ARM_IRQ_TYPE_SHIFT)
-        | (cpu << KVM_ARM_IRQ_VCPU_SHIFT) | irq;
-
-    kvm_set_irq(kvm_state, kvm_irq, !!level);
+    kvm_arm_set_irq(cpu, irqtype, irq, !!level);
 }
 
 static void kvm_arm_gicv2_set_irq(void *opaque, int irq, int level)
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 2399c14471..13813fb213 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -576,16 +576,16 @@ static void arm_cpu_kvm_set_irq(void *opaque, int irq, 
int level)
     ARMCPU *cpu = opaque;
     CPUARMState *env = &cpu->env;
     CPUState *cs = CPU(cpu);
-    int kvm_irq = KVM_ARM_IRQ_TYPE_CPU << KVM_ARM_IRQ_TYPE_SHIFT;
     uint32_t linestate_bit;
+    int irq_id;
 
     switch (irq) {
     case ARM_CPU_IRQ:
-        kvm_irq |= KVM_ARM_IRQ_CPU_IRQ;
+        irq_id = KVM_ARM_IRQ_CPU_IRQ;
         linestate_bit = CPU_INTERRUPT_HARD;
         break;
     case ARM_CPU_FIQ:
-        kvm_irq |= KVM_ARM_IRQ_CPU_FIQ;
+        irq_id = KVM_ARM_IRQ_CPU_FIQ;
         linestate_bit = CPU_INTERRUPT_FIQ;
         break;
     default:
@@ -597,9 +597,7 @@ static void arm_cpu_kvm_set_irq(void *opaque, int irq, int 
level)
     } else {
         env->irq_line_state &= ~linestate_bit;
     }
-
-    kvm_irq |= cs->cpu_index << KVM_ARM_IRQ_VCPU_SHIFT;
-    kvm_set_irq(kvm_state, kvm_irq, level ? 1 : 0);
+    kvm_arm_set_irq(cs->cpu_index, KVM_ARM_IRQ_TYPE_CPU, irq_id, !!level);
 #endif
 }
 
diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index b2eaa50b8d..6cdfa2204f 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -744,6 +744,22 @@ int kvm_arm_vgic_probe(void)
     }
 }
 
+int kvm_arm_set_irq(int cpu, int irqtype, int irq, int level)
+{
+    int kvm_irq = 0;
+
+    kvm_irq = (irqtype << KVM_ARM_IRQ_TYPE_SHIFT) | irq;
+
+    if (cpu != 0) {
+        int cpu_idx2 = cpu / 256;
+        int cpu_idx1 = cpu % 256;
+
+        kvm_irq |= (cpu_idx1 << KVM_ARM_IRQ_VCPU_SHIFT) |
+           ((cpu_idx2 & KVM_ARM_IRQ_VCPU2_MASK) << KVM_ARM_IRQ_VCPU2_SHIFT);
+    }
+    return kvm_set_irq(kvm_state, kvm_irq, !!level);
+}
+
 int kvm_arch_fixup_msi_route(struct kvm_irq_routing_entry *route,
                              uint64_t address, uint32_t data, PCIDevice *dev)
 {
diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
index b3106c8600..b4e19457a0 100644
--- a/target/arm/kvm_arm.h
+++ b/target/arm/kvm_arm.h
@@ -253,6 +253,7 @@ int kvm_arm_vgic_probe(void);
 
 void kvm_arm_pmu_set_irq(CPUState *cs, int irq);
 void kvm_arm_pmu_init(CPUState *cs);
+int kvm_arm_set_irq(int cpu, int irqtype, int irq, int level);
 
 #else
 
-- 
2.20.1