[Qemu-devel] [PATCH 12/35] hax: access cpu->interrupt_request with atomics

[Emilio G. Cota]

I am not familiar with hax, so I opted for the safe
(and slow) route of performing probably many unnecessary
atomic_reads.

Cc: Richard Henderson <r...@twiddle.net>
Cc: Eduardo Habkost <ehabk...@redhat.com>
Signed-off-by: Emilio G. Cota <c...@braap.org>
---
 target/i386/hax-all.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/target/i386/hax-all.c b/target/i386/hax-all.c
index ae8b678db0..56f999d5ba 100644
--- a/target/i386/hax-all.c
+++ b/target/i386/hax-all.c
@@ -293,7 +293,7 @@ int hax_vm_destroy(struct hax_vm *vm)
 
 static void hax_handle_interrupt(CPUState *cpu, int mask)
 {
-    cpu->interrupt_request |= mask;
+    atomic_or(&cpu->interrupt_request, mask);
 
     if (!qemu_cpu_is_self(cpu)) {
         qemu_cpu_kick(cpu);
@@ -427,7 +427,7 @@ static int hax_vcpu_interrupt(CPUArchState *env)
      * Unlike KVM, HAX kernel check for the eflags, instead of qemu
      */
     if (ht->ready_for_interrupt_injection &&
-        (cpu->interrupt_request & CPU_INTERRUPT_HARD)) {
+        (atomic_read(&cpu->interrupt_request) & CPU_INTERRUPT_HARD)) {
         int irq;
 
         irq = cpu_get_pic_interrupt(env);
@@ -441,7 +441,7 @@ static int hax_vcpu_interrupt(CPUArchState *env)
      * interrupt, request an interrupt window exit.  This will
      * cause a return to userspace as soon as the guest is ready to
      * receive interrupts. */
-    if ((cpu->interrupt_request & CPU_INTERRUPT_HARD)) {
+    if (atomic_read(&cpu->interrupt_request) & CPU_INTERRUPT_HARD) {
         ht->request_interrupt_window = 1;
     } else {
         ht->request_interrupt_window = 0;
@@ -482,19 +482,19 @@ static int hax_vcpu_hax_exec(CPUArchState *env)
 
     cpu->halted = 0;
 
-    if (cpu->interrupt_request & CPU_INTERRUPT_POLL) {
+    if (atomic_read(&cpu->interrupt_request) & CPU_INTERRUPT_POLL) {
         cpu_reset_interrupt(cpu, CPU_INTERRUPT_POLL);
         apic_poll_irq(x86_cpu->apic_state);
     }
 
-    if (cpu->interrupt_request & CPU_INTERRUPT_INIT) {
+    if (atomic_read(&cpu->interrupt_request) & CPU_INTERRUPT_INIT) {
         DPRINTF("\nhax_vcpu_hax_exec: handling INIT for %d\n",
                 cpu->cpu_index);
         do_cpu_init(x86_cpu);
         hax_vcpu_sync_state(env, 1);
     }
 
-    if (cpu->interrupt_request & CPU_INTERRUPT_SIPI) {
+    if (atomic_read(&cpu->interrupt_request) & CPU_INTERRUPT_SIPI) {
         DPRINTF("hax_vcpu_hax_exec: handling SIPI for %d\n",
                 cpu->cpu_index);
         hax_vcpu_sync_state(env, 0);
@@ -503,6 +503,7 @@ static int hax_vcpu_hax_exec(CPUArchState *env)
     }
 
     do {
+        int interrupt_request;
         int hax_ret;
 
         if (cpu->exit_request) {
@@ -553,8 +554,9 @@ static int hax_vcpu_hax_exec(CPUArchState *env)
             ret = -1;
             break;
         case HAX_EXIT_HLT:
-            if (!(cpu->interrupt_request & CPU_INTERRUPT_HARD) &&
-                !(cpu->interrupt_request & CPU_INTERRUPT_NMI)) {
+            interrupt_request = atomic_read(&cpu->interrupt_request);
+            if (!(interrupt_request & CPU_INTERRUPT_HARD) &&
+                !(interrupt_request & CPU_INTERRUPT_NMI)) {
                 /* hlt instruction with interrupt disabled is shutdown */
                 env->eflags |= IF_MASK;
                 cpu->halted = 1;
-- 
2.17.1