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authorPeter Maydell <peter.maydell@linaro.org>2024-04-30 15:00:34 +0100
committerPeter Maydell <peter.maydell@linaro.org>2024-05-30 16:13:48 +0100
commit408b2b3d9df631102919ada62add6d785f737f74 (patch)
treefb913341f3f1772002acf991b1159ea782da4f1d /target
parentaf3f5c4f8728c6d2ae0081fc38d66e9484cc391e (diff)
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accel/tcg: Make TCGCPUOps::cpu_exec_halt return bool for whether to halt
The TCGCPUOps::cpu_exec_halt method is called from cpu_handle_halt() when the CPU is halted, so that a target CPU emulation can do anything target-specific it needs to do. (At the moment we only use this on i386.) The current specification of the method doesn't allow the target specific code to do something different if the CPU is about to come out of the halt state, because cpu_handle_halt() only determines this after the method has returned. (If the method called cpu_has_work() itself this would introduce a potential race if an interrupt arrived between the target's method implementation checking and cpu_handle_halt() repeating the check.) Change the definition of the method so that it returns a bool to tell cpu_handle_halt() whether to stay in halt or not. We will want this for the Arm target, where FEAT_WFxT wants to do some work only for the case where the CPU is in halt but about to leave it. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20240430140035.3889879-2-peter.maydell@linaro.org
Diffstat (limited to 'target')
-rw-r--r--target/i386/tcg/helper-tcg.h2
-rw-r--r--target/i386/tcg/sysemu/seg_helper.c3
2 files changed, 3 insertions, 2 deletions
diff --git a/target/i386/tcg/helper-tcg.h b/target/i386/tcg/helper-tcg.h
index effc2c1..8595794 100644
--- a/target/i386/tcg/helper-tcg.h
+++ b/target/i386/tcg/helper-tcg.h
@@ -39,7 +39,7 @@ QEMU_BUILD_BUG_ON(TCG_PHYS_ADDR_BITS > TARGET_PHYS_ADDR_SPACE_BITS);
*/
void x86_cpu_do_interrupt(CPUState *cpu);
#ifndef CONFIG_USER_ONLY
-void x86_cpu_exec_halt(CPUState *cpu);
+bool x86_cpu_exec_halt(CPUState *cpu);
bool x86_need_replay_interrupt(int interrupt_request);
bool x86_cpu_exec_interrupt(CPUState *cpu, int int_req);
#endif
diff --git a/target/i386/tcg/sysemu/seg_helper.c b/target/i386/tcg/sysemu/seg_helper.c
index 2db8083..9ba94de 100644
--- a/target/i386/tcg/sysemu/seg_helper.c
+++ b/target/i386/tcg/sysemu/seg_helper.c
@@ -128,7 +128,7 @@ void x86_cpu_do_interrupt(CPUState *cs)
}
}
-void x86_cpu_exec_halt(CPUState *cpu)
+bool x86_cpu_exec_halt(CPUState *cpu)
{
if (cpu->interrupt_request & CPU_INTERRUPT_POLL) {
X86CPU *x86_cpu = X86_CPU(cpu);
@@ -138,6 +138,7 @@ void x86_cpu_exec_halt(CPUState *cpu)
cpu_reset_interrupt(cpu, CPU_INTERRUPT_POLL);
bql_unlock();
}
+ return cpu_has_work(cpu);
}
bool x86_need_replay_interrupt(int interrupt_request)