Fix interrupt exclusion via SSTEP_NOIRQ
PATCH 1/1 Fix interrupt exclusion via SSTEP_NOIRQ
Commit #5620 revealed an issue of the SSTEP_NOIRQ masking that was applied on all interrupt sources (including internal ones) when single stepping through the guest. Due to that commit, we now ended up in an infinite loop when CPU_INTERRUPT_EXIT was pending on SSTEP resume. That was due to #5620 eating all TBs while CPU_INTERRUPT_EXIT is pending, but SSTEP_NOIRQ preventing CPU_INTERRUPT_EXIT to be processed.
What SSTEP_NOIRQ should actually do is to block the delivery of all external, guest visible interrupts. With the fix below applied, single stepping now works again.
Signed-off-by Jan Kiszka <[email protected]>
--- cpu-exec.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
cpu-exec.c +8 -2
@@ -384,8 +384,14 @@ int cpu_exec(CPUState *env1) next_tb =0 ;/* force lookup of first TB */ for (;;) { interrupt_request = env->interrupt_request; -if (unlikely (interrupt_request) && -likely (!(env->singlestep_enabled &SSTEP_NOIRQ ))) { +if (unlikely (interrupt_request)) { +if (unlikely (env->singlestep_enabled &SSTEP_NOIRQ )) { +/* Mask out external interrupts for this step. */ + interrupt_request &= ~(CPU_INTERRUPT_HARD | +CPU_INTERRUPT_FIQ | +CPU_INTERRUPT_SMI | +CPU_INTERRUPT_NMI ); + }if (interrupt_request &CPU_INTERRUPT_DEBUG ) { env->interrupt_request &= ~CPU_INTERRUPT_DEBUG ; env->exception_index =EXCP_DEBUG ;
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