Hi list,
I am trying to figure out when & how a interrupt handler of the guest
is called after Xen sets evtchn_upcall_pending to non-zero. Below is
my understanding. Please let me know if something is wrong.
When Xen wants to inject an interrupt to the guest, the following
functions are called sequentially.
send_guest_vcpu_virq()-->evtchn_set_pending()-->vcpu_mark_events_pending()-->vcpu_kick()-->cpu_raise_softirq()-->smp_send_event_check_cpu()-->send_IPI_mask(mask,
EVENT_CHECK_VECTOR). Then an interrupt handler will handle this IPI
with vector EVENT_CHECK_VECTOR. I think within this interrupt handler,
Xen calls the registered virtual interrupt handler of the guest. Right
or not?
The IPI handler is defined as
BUILD_SMP_INTERRUPT(event_check_interrupt,EVENT_CHECK_VECTOR),
then the definition of this macro goes here,
#define BUILD_SMP_INTERRUPT(x,v) XBUILD_SMP_INTERRUPT(x,v)
#define XBUILD_SMP_INTERRUPT(x,v) \
asmlinkage void x(void); \
__asm__( \
 "\n"__ALIGN_STR"\n" \
 ".globl " STR(x) "\n\t" \
 STR(x) ":\n\t" \
 "pushl $"#v"<<16\n\t" \
 STR(FIXUP_RING0_GUEST_STACK) \
 STR(SAVE_ALL(1f,1f)) "\n\t" \
 "1:movl %esp,%eax\n\t" \
 "pushl %eax\n\t" \
 "call "STR(smp_##x)"\n\t" \
 "addl 4,ドル%esp\n\t" \
 "jmp ret_from_intr\n");
Inside this assembly code block, smp_event_check_interrupt() is
called. Then I could not find where this function is defined..
Any comments?
Thanks,
Jiaqing
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