diff mbox series

hw/intc/ioapic: Delete a wrong IRQ redirection on I/O APIC

Message ID TY0PR0101MB42850337F8917D1F514107FBA4D52@TY0PR0101MB4285.apcprd01.prod.exchangelabs.com (mailing list archive)
State New
Headers show
Series hw/intc/ioapic: Delete a wrong IRQ redirection on I/O APIC | expand

Commit Message

TaiseiIto June 25, 2024, 12:03 p.m. UTC 
Before this commit, interruptions from i8254 which should be sent to IRQ0
were sent to IRQ2. After this commit, these are correctly sent to IRQ0. When
I had an HPET timer generate interruptions once per second to test an HPET
driver in my operating system on QEMU, I observed more frequent
interruptions than I configured on the HPET timer. I investigated the cause
and found that not only interruptions from HPET but also interruptions from
i8254 were sent to IRQ2 because of a redirection from IRQ0 to IRQ2. This
redirection is added in hw/apic.c at commit
16b29ae1807b024bd5052301550f5d47dae958a2 but this redirection caused wrong
interruptions. So I deleted the redirection. Finally, I confirmed there is
no problem on 'make check' results and that interruptions from i8254 and
interruptions from HPET are correclty sent to IRQ0 and IRQ2 respectively.

Signed-off-by: TaiseiIto <taisei1212@outlook.jp>
---
 hw/intc/ioapic.c | 7 -------
 1 file changed, 7 deletions(-)
diff mbox series

Patch

diff --git a/hw/intc/ioapic.c b/hw/intc/ioapic.c
index 716ffc8bbb..6b630b45ca 100644
--- a/hw/intc/ioapic.c
+++ b/hw/intc/ioapic.c
@@ -154,15 +154,8 @@  static void ioapic_set_irq(void *opaque, int vector, int level)
 {
     IOAPICCommonState *s = opaque;
 
-    /* ISA IRQs map to GSI 1-1 except for IRQ0 which maps
-     * to GSI 2.  GSI maps to ioapic 1-1.  This is not
-     * the cleanest way of doing it but it should work. */
-
     trace_ioapic_set_irq(vector, level);
     ioapic_stat_update_irq(s, vector, level);
-    if (vector == 0) {
-        vector = 2;
-    }
     if (vector < IOAPIC_NUM_PINS) {
         uint32_t mask = 1 << vector;
         uint64_t entry = s->ioredtbl[vector];