[PATCH 3/4] accel/hvf: Make async_safe_run_on_cpu() safe

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

Wrap hv_vcpu_run() calls with cpu_exec_start/end() in order to
have the main loop perform more exclusive sections while all
vCPUs are quiescent.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
Could be related to the dubious thread_kicked access and pselect() in
hvf_wait_for_ipi() (commit 219c101fa7f "arm/hvf: Add a WFI handler").

Cc: Peter Collingbourne <pcc@google.com>
Cc: Alexander Graf <agraf@csgraf.de>
Cc: Roman Bolshakov <r.bolshakov@yadro.com>
Cc: Sergio Lopez <slp@redhat.com>
---
 target/arm/hvf/hvf.c  | 2 ++
 target/i386/hvf/hvf.c | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
index b77db99079e..377eb4bbc6b 100644
--- a/target/arm/hvf/hvf.c
+++ b/target/arm/hvf/hvf.c
@@ -1927,7 +1927,9 @@ int hvf_vcpu_exec(CPUState *cpu)
     flush_cpu_state(cpu);
 
     bql_unlock();
+    cpu_exec_start(cpu);
     r = hv_vcpu_run(cpu->accel->fd);
+    cpu_exec_end(cpu);
     bql_lock();
     switch (r) {
     case HV_SUCCESS:
diff --git a/target/i386/hvf/hvf.c b/target/i386/hvf/hvf.c
index 8445cadecec..913ad47f3d8 100644
--- a/target/i386/hvf/hvf.c
+++ b/target/i386/hvf/hvf.c
@@ -749,8 +749,10 @@ int hvf_vcpu_exec(CPUState *cpu)
             return EXCP_HLT;
         }
 
+        cpu_exec_start(cpu);
         hv_return_t r = hv_vcpu_run_until(cpu->accel->fd, HV_DEADLINE_FOREVER);
         assert_hvf_ok(r);
+        cpu_exec_end(cpu);
 
         /* handle VMEXIT */
         uint64_t exit_reason = rvmcs(cpu->accel->fd, VMCS_EXIT_REASON);
-- 
2.51.0