[PATCH 4/8] i386: hvf: Implement CPU kick

[Roman Bolshakov]

HVF doesn't have a CPU kick and without it it's not possible to perform
an action on CPU thread until a VMEXIT happens. The kick is also needed
for timely interrupt delivery.

Existing implementation of CPU kick sends SIG_IPI (aka SIGUSR1) to vCPU
thread, but it's different from what hv_vcpu_interrupt does. The latter
one results in invocation of mp_cpus_kick() in XNU kernel [1].

While at it, correct type of hvf_fd to the type of hv_vcpuid_t to avoid
compilation warnings.

1. https://opensource.apple.com/source/xnu/xnu-6153.81.5/osfmk/i386/mp.c

Cc: Cameron Esfahani <dirty@apple.com>
Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
---
 cpus.c                | 13 +++++++++----
 include/hw/core/cpu.h |  2 +-
 include/sysemu/hvf.h  |  1 +
 target/i386/hvf/hvf.c | 11 +++++++++++
 4 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/cpus.c b/cpus.c
index 26709677d3..36f38ce5c8 100644
--- a/cpus.c
+++ b/cpus.c
@@ -1783,10 +1783,15 @@ static void qemu_cpu_kick_thread(CPUState *cpu)
         return;
     }
     cpu->thread_kicked = true;
-    err = pthread_kill(cpu->thread->thread, SIG_IPI);
-    if (err && err != ESRCH) {
-        fprintf(stderr, "qemu:%s: %s", __func__, strerror(err));
-        exit(1);
+
+    if (hvf_enabled()) {
+        hvf_vcpu_kick(cpu);
+    } else {
+        err = pthread_kill(cpu->thread->thread, SIG_IPI);
+        if (err && err != ESRCH) {
+            fprintf(stderr, "qemu:%s: %s", __func__, strerror(err));
+            exit(1);
+        }
     }
 #else /* _WIN32 */
     if (!qemu_cpu_is_self(cpu)) {
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index b3f4b79318..288a2bd57e 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -438,7 +438,7 @@ struct CPUState {
 
     struct hax_vcpu_state *hax_vcpu;
 
-    int hvf_fd;
+    unsigned hvf_fd;
 
     /* track IOMMUs whose translations we've cached in the TCG TLB */
     GArray *iommu_notifiers;
diff --git a/include/sysemu/hvf.h b/include/sysemu/hvf.h
index 1d40a8ec01..aaa00cbf05 100644
--- a/include/sysemu/hvf.h
+++ b/include/sysemu/hvf.h
@@ -25,6 +25,7 @@ extern bool hvf_allowed;
 
 int hvf_init_vcpu(CPUState *);
 int hvf_vcpu_exec(CPUState *);
+void hvf_vcpu_kick(CPUState *);
 void hvf_cpu_synchronize_state(CPUState *);
 void hvf_cpu_synchronize_post_reset(CPUState *);
 void hvf_cpu_synchronize_post_init(CPUState *);
diff --git a/target/i386/hvf/hvf.c b/target/i386/hvf/hvf.c
index efe9802962..4d254a477a 100644
--- a/target/i386/hvf/hvf.c
+++ b/target/i386/hvf/hvf.c
@@ -966,6 +966,17 @@ int hvf_vcpu_exec(CPUState *cpu)
     return ret;
 }
 
+void hvf_vcpu_kick(CPUState *cpu)
+{
+    hv_return_t err;
+
+    err = hv_vcpu_interrupt(&cpu->hvf_fd, 1);
+    if (err) {
+        fprintf(stderr, "qemu:%s error %#x\n", __func__, err);
+        exit(1);
+    }
+}
+
 bool hvf_allowed;
 
 static int hvf_accel_init(MachineState *ms)
-- 
2.26.1