tcg: move interrupt caching and single step masking closer to user

in cpu_handle_interrupt() the only place where cached interrupt_request
might have effect is when CPU_INTERRUPT_SSTEP_MASK applied and
cached interrupt_request handed over to cpu_exec_interrupt() and
need_replay_interrupt().

Simplify code by moving interrupt_request caching and CPU_INTERRUPT_SSTEP_MASK
masking into the block where it actually matters and drop reloading cached value
from CPUState:interrupt_request as the rest of the code directly uses
CPUState:interrupt_request.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Link: https://lore.kernel.org/r/20250814160600.2327672-9-imammedo@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 6 insertions, 9 deletions

diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index 96c124a..8491e5b 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -782,13 +782,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
     assert(!cpu_test_interrupt(cpu, ~0));
 #else
     if (unlikely(cpu_test_interrupt(cpu, ~0))) {
-        int interrupt_request;
         bql_lock();
-        interrupt_request = cpu->interrupt_request;
-        if (unlikely(cpu->singlestep_enabled & SSTEP_NOIRQ)) {
-            /* Mask out external interrupts for this step. */
-            interrupt_request &= ~CPU_INTERRUPT_SSTEP_MASK;
-        }
         if (cpu_test_interrupt(cpu, CPU_INTERRUPT_DEBUG)) {
             cpu->interrupt_request &= ~CPU_INTERRUPT_DEBUG;
             cpu->exception_index = EXCP_DEBUG;
@@ -806,6 +800,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
             return true;
         } else {
             const TCGCPUOps *tcg_ops = cpu->cc->tcg_ops;
+            int interrupt_request = cpu->interrupt_request;
 
             if (cpu_test_interrupt(cpu, CPU_INTERRUPT_RESET)) {
                 replay_interrupt();
@@ -814,6 +809,11 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
                 return true;
             }
 
+            if (unlikely(cpu->singlestep_enabled & SSTEP_NOIRQ)) {
+                /* Mask out external interrupts for this step. */
+                interrupt_request &= ~CPU_INTERRUPT_SSTEP_MASK;
+            }
+
             /*
              * The target hook has 3 exit conditions:
              * False when the interrupt isn't processed,
@@ -838,9 +838,6 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
                 cpu->exception_index = -1;
                 *last_tb = NULL;
             }
-            /* The target hook may have updated the 'cpu->interrupt_request';
-             * reload the 'interrupt_request' value */
-            interrupt_request = cpu->interrupt_request;
         }
         if (cpu_test_interrupt(cpu, CPU_INTERRUPT_EXITTB)) {
             cpu->interrupt_request &= ~CPU_INTERRUPT_EXITTB;