[MIPS] Add Goldfish target support

Basic Goldfish support for MIPS.

Also, Fix host CPU consumption when guest is idle

When the CPU is in wait state, do not wake-up if an interrupt can't be
taken. This avoid host CPU running at 100% if a device (e.g. timer) has
an interrupt line left enabled.

Also factorize code to check if interrupts are enabled in
cpu_mips_hw_interrupts_pending().

CPU consumption based on a patch from
Edgar E. Iglesias <edgar.iglesias@gmail.com>

Change-Id: Ie8371c8d0c9af1e0c8ba4cac419979350de0f5d9
Signed-off-by: yajin <yajin@mips.com.cm>
Signed-off-by: Douglas Leung <douglas@mips.com>
Signed-off-by: Bhanu Chetlapalli <bhanu@mips.com>
Signed-off-by: Chris Dearman <chris@mips.com>

1 files changed, 15 insertions, 3 deletions

diff --git a/target-mips/exec.h b/target-mips/exec.h
index 8a118bb..0720366 100644
--- a/target-mips/exec.h
+++ b/target-mips/exec.h
@@ -35,10 +35,22 @@ static inline void regs_to_env(void)
 
 static inline int cpu_has_work(CPUState *env)
 {
-    return (env->interrupt_request &
-            (CPU_INTERRUPT_HARD | CPU_INTERRUPT_TIMER));
-}
+    int has_work = 0;
+
+    /* It is implementation dependent if non-enabled interrupts
+       wake-up the CPU, however most of the implementations only
+       check for interrupts that can be taken. */
+    if ((env->interrupt_request & CPU_INTERRUPT_HARD) &&
+        cpu_mips_hw_interrupts_pending(env)) {
+        has_work = 1;
+    }
 
+    if (env->interrupt_request & CPU_INTERRUPT_TIMER) {
+        has_work = 1;
+    }
+
+    return has_work;
+}
 
 static inline int cpu_halted(CPUState *env)
 {