From 8d04fb55dec381bc5105cb47f29d918e579e8cbd Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Thu, 23 Feb 2017 18:29:11 +0000 Subject: tcg: drop global lock during TCG code execution MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This finally allows TCG to benefit from the iothread introduction: Drop the global mutex while running pure TCG CPU code. Reacquire the lock when entering MMIO or PIO emulation, or when leaving the TCG loop. We have to revert a few optimization for the current TCG threading model, namely kicking the TCG thread in qemu_mutex_lock_iothread and not kicking it in qemu_cpu_kick. We also need to disable RAM block reordering until we have a more efficient locking mechanism at hand. Still, a Linux x86 UP guest and my Musicpal ARM model boot fine here. These numbers demonstrate where we gain something: 20338 jan 20 0 331m 75m 6904 R 99 0.9 0:50.95 qemu-system-arm 20337 jan 20 0 331m 75m 6904 S 20 0.9 0:26.50 qemu-system-arm The guest CPU was fully loaded, but the iothread could still run mostly independent on a second core. Without the patch we don't get beyond 32206 jan 20 0 330m 73m 7036 R 82 0.9 1:06.00 qemu-system-arm 32204 jan 20 0 330m 73m 7036 S 21 0.9 0:17.03 qemu-system-arm We don't benefit significantly, though, when the guest is not fully loading a host CPU. Signed-off-by: Jan Kiszka Message-Id: <1439220437-23957-10-git-send-email-fred.konrad@greensocs.com> [FK: Rebase, fix qemu_devices_reset deadlock, rm address_space_* mutex] Signed-off-by: KONRAD Frederic [EGC: fixed iothread lock for cpu-exec IRQ handling] Signed-off-by: Emilio G. Cota [AJB: -smp single-threaded fix, clean commit msg, BQL fixes] Signed-off-by: Alex Bennée Reviewed-by: Richard Henderson Reviewed-by: Pranith Kumar [PM: target-arm changes] Acked-by: Peter Maydell --- target/i386/smm_helper.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'target/i386') diff --git a/target/i386/smm_helper.c b/target/i386/smm_helper.c index 4dd6a2c544..f051a77c4a 100644 --- a/target/i386/smm_helper.c +++ b/target/i386/smm_helper.c @@ -18,6 +18,7 @@ */ #include "qemu/osdep.h" +#include "qemu/main-loop.h" #include "cpu.h" #include "exec/helper-proto.h" #include "exec/log.h" @@ -42,11 +43,14 @@ void helper_rsm(CPUX86State *env) #define SMM_REVISION_ID 0x00020000 #endif +/* Called with iothread lock taken */ void cpu_smm_update(X86CPU *cpu) { CPUX86State *env = &cpu->env; bool smm_enabled = (env->hflags & HF_SMM_MASK); + g_assert(qemu_mutex_iothread_locked()); + if (cpu->smram) { memory_region_set_enabled(cpu->smram, smm_enabled); } @@ -333,7 +337,10 @@ void helper_rsm(CPUX86State *env) } env->hflags2 &= ~HF2_SMM_INSIDE_NMI_MASK; env->hflags &= ~HF_SMM_MASK; + + qemu_mutex_lock_iothread(); cpu_smm_update(cpu); + qemu_mutex_unlock_iothread(); qemu_log_mask(CPU_LOG_INT, "SMM: after RSM\n"); log_cpu_state_mask(CPU_LOG_INT, CPU(cpu), CPU_DUMP_CCOP); -- cgit v1.2.3