[Qemu-devel] [PATCH v5] ppc: remove the idle_timer logic

[Shivaprasad G Bhat]

The KVM_CAP_PPC_IRQ_LEVEL is part of the kernel now since 2.6.37.
Drop the redundant logic which is not excercised on new the kernels anymore.

Signed-off-by: Shivaprasad G Bhat <address@hidden>
---
 v4: https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg04456.html
 Changes from v4:
   - it was discussed to drop the idle_timer logic instead of fixing the
     leak and keeping the redundant logic around. So, the patch does that.

 target/ppc/kvm.c |   74 +-----------------------------------------------------
 1 file changed, 2 insertions(+), 72 deletions(-)

diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index 8a06d3171e..1c8f2319a0 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -56,7 +56,6 @@ const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
 };
 
 static int cap_interrupt_unset;
-static int cap_interrupt_level;
 static int cap_segstate;
 static int cap_booke_sregs;
 static int cap_ppc_smt;
@@ -87,25 +86,6 @@ static int cap_large_decr;
 
 static uint32_t debug_inst_opcode;
 
-/*
- * XXX We have a race condition where we actually have a level triggered
- *     interrupt, but the infrastructure can't expose that yet, so the guest
- *     takes but ignores it, goes to sleep and never gets notified that there's
- *     still an interrupt pending.
- *
- *     As a quick workaround, let's just wake up again 20 ms after we injected
- *     an interrupt. That way we can assure that we're always reinjecting
- *     interrupts in case the guest swallowed them.
- */
-static QEMUTimer *idle_timer;
-
-static void kvm_kick_cpu(void *opaque)
-{
-    PowerPCCPU *cpu = opaque;
-
-    qemu_cpu_kick(CPU(cpu));
-}
-
 /*
  * Check whether we are running with KVM-PR (instead of KVM-HV).  This
  * should only be used for fallback tests - generally we should use
@@ -125,7 +105,6 @@ static int kvmppc_get_dec_bits(void);
 int kvm_arch_init(MachineState *ms, KVMState *s)
 {
     cap_interrupt_unset = kvm_check_extension(s, KVM_CAP_PPC_UNSET_IRQ);
-    cap_interrupt_level = kvm_check_extension(s, KVM_CAP_PPC_IRQ_LEVEL);
     cap_segstate = kvm_check_extension(s, KVM_CAP_PPC_SEGSTATE);
     cap_booke_sregs = kvm_check_extension(s, KVM_CAP_PPC_BOOKE_SREGS);
     cap_ppc_smt_possible = kvm_vm_check_extension(s, KVM_CAP_PPC_SMT_POSSIBLE);
@@ -161,11 +140,6 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
      */
     cap_ppc_pvr_compat = false;
 
-    if (!cap_interrupt_level) {
-        fprintf(stderr, "KVM: Couldn't find level irq capability. Expect the "
-                        "VM to stall at times!\n");
-    }
-
     kvm_ppc_register_host_cpu_type(ms);
 
     return 0;
@@ -491,8 +465,6 @@ int kvm_arch_init_vcpu(CPUState *cs)
         return ret;
     }
 
-    idle_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, kvm_kick_cpu, cpu);
-
     switch (cenv->mmu_model) {
     case POWERPC_MMU_BOOKE206:
         /* This target supports access to KVM's guest TLB */
@@ -1332,7 +1304,7 @@ int kvmppc_set_interrupt(PowerPCCPU *cpu, int irq, int 
level)
         return 0;
     }
 
-    if (!kvm_enabled() || !cap_interrupt_unset || !cap_interrupt_level) {
+    if (!kvm_enabled() || !cap_interrupt_unset) {
         return 0;
     }
 
@@ -1349,49 +1321,7 @@ int kvmppc_set_interrupt(PowerPCCPU *cpu, int irq, int 
level)
 
 void kvm_arch_pre_run(CPUState *cs, struct kvm_run *run)
 {
-    PowerPCCPU *cpu = POWERPC_CPU(cs);
-    CPUPPCState *env = &cpu->env;
-    int r;
-    unsigned irq;
-
-    qemu_mutex_lock_iothread();
-
-    /*
-     * PowerPC QEMU tracks the various core input pins (interrupt,
-     * critical interrupt, reset, etc) in PPC-specific
-     * env->irq_input_state.
-     */
-    if (!cap_interrupt_level &&
-        run->ready_for_interrupt_injection &&
-        (cs->interrupt_request & CPU_INTERRUPT_HARD) &&
-        (env->irq_input_state & (1 << PPC_INPUT_INT)))
-    {
-        /*
-         * For now KVM disregards the 'irq' argument. However, in the
-         * future KVM could cache it in-kernel to avoid a heavyweight
-         * exit when reading the UIC.
-         */
-        irq = KVM_INTERRUPT_SET;
-
-        trace_kvm_injected_interrupt(irq);
-        r = kvm_vcpu_ioctl(cs, KVM_INTERRUPT, &irq);
-        if (r < 0) {
-            printf("cpu %d fail inject %x\n", cs->cpu_index, irq);
-        }
-
-        /* Always wake up soon in case the interrupt was level based */
-        timer_mod(idle_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
-                       (NANOSECONDS_PER_SECOND / 50));
-    }
-
-    /*
-     * We don't know if there are more interrupts pending after
-     * this. However, the guest will return to userspace in the course
-     * of handling this one anyways, so we will get a chance to
-     * deliver the rest.
-     */
-
-    qemu_mutex_unlock_iothread();
+    return;
 }
 
 MemTxAttrs kvm_arch_post_run(CPUState *cs, struct kvm_run *run)