diff options
| author | Aurelien Jarno <aurelien@aurel32.net> | 2010-12-25 22:56:32 +0100 |
|---|---|---|
| committer | Aurelien Jarno <aurelien@aurel32.net> | 2010-12-27 00:58:06 +0100 |
| commit | 4cdc1cd137e0b98766916a7cdf2d5a9b3c6632fa (patch) | |
| tree | 4634bbca8423124883394dcf88957a3ed52ce0b0 /target-mips | |
| parent | 6c33286ad3a432627d763ee93aa42200cbb68269 (diff) | |
| download | qemu-4cdc1cd137e0b98766916a7cdf2d5a9b3c6632fa.zip qemu-4cdc1cd137e0b98766916a7cdf2d5a9b3c6632fa.tar.gz qemu-4cdc1cd137e0b98766916a7cdf2d5a9b3c6632fa.tar.bz2 | |
target-mips: 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().
Based on a patch from Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Acked-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Diffstat (limited to 'target-mips')
| -rw-r--r-- | target-mips/cpu.h | 8 | ||||
| -rw-r--r-- | target-mips/exec.h | 18 |
2 files changed, 23 insertions, 3 deletions
diff --git a/target-mips/cpu.h b/target-mips/cpu.h index c1f211f..2419aa9 100644 --- a/target-mips/cpu.h +++ b/target-mips/cpu.h @@ -532,6 +532,14 @@ static inline int cpu_mips_hw_interrupts_pending(CPUState *env) int32_t status; int r; + if (!(env->CP0_Status & (1 << CP0St_IE)) || + (env->CP0_Status & (1 << CP0St_EXL)) || + (env->CP0_Status & (1 << CP0St_ERL)) || + (env->hflags & MIPS_HFLAG_DM)) { + /* Interrupts are disabled */ + return 0; + } + pending = env->CP0_Cause & CP0Ca_IP_mask; status = env->CP0_Status & CP0Ca_IP_mask; diff --git a/target-mips/exec.h b/target-mips/exec.h index af61b54..1273654 100644 --- a/target-mips/exec.h +++ b/target-mips/exec.h @@ -19,10 +19,22 @@ register struct CPUMIPSState *env asm(AREG0); 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) { |