hw/intc: apic: disallow APIC reads when disabled
!APICBASE_ENABLE + attempting to read xAPIC registers is not an allowed combination. And neither is x2APIC enabled + attempting to read xAPIC registers Signed-off-by: Mohamed Mediouni <mohamed@unpredictable.fr> Link: https://lore.kernel.org/r/20260422214225.2242-15-mohamed@unpredictable.fr Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Mohamed Mediouni committed
Apr 22, 2026 at 23:42 UTC
72bef33b1553497079a5feff9f46c64c7d3f1ad3
1 file changed
+9
hw/intc/apic.c
+9
@@ -875,6 +875,15 @@ static uint64_t apic_mem_read(void *opaque, hwaddr addr, unsigned size)
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return -1;
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}
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+ /* if the xAPIC is disabled, return early. */
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+ if (!(s->apicbase & MSR_IA32_APICBASE_ENABLE)) {
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+ return 0xffffffff;
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+ }
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+
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+ if (is_x2apic_mode(s)) {
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+ return 0xffffffff;
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+ }
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+
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index = (addr >> 4) & 0xff;
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apic_register_read(s, index, &val);
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