Re: [Qemu-devel] QEMU APIC version ID bug?

[Neil McGill]

APIC ver register is 1 but *IO*APIC ver register is 3... sorry for the 
confusion/noise, qemu looks fine

neil

On 4/16/14 10:16 AM, Neil McGill wrote:
> Seems there is a bug in qemu where the APIC version is being checked as
> value 3. However, it should be 1.
>
> static uint32_t apic_mem_readl(void *opaque, hwaddr addr)
> {
> ...
>      switch(index) {
>      case 0x03: /* version */
>          val = 0x11 | ((APIC_LVT_NB - 1) << 16); /* version 0x11 */
>          break;
>
> Comparing to KVM, it has the correct value:
>
> static unsigned long ioapic_read_indirect(struct kvm_ioapic *ioapic,
>                        unsigned long addr,
>                        unsigned long length)
> {
>      unsigned long result = 0;
>
>      switch (ioapic->ioregsel) {
>      case IOAPIC_REG_VERSION:
>          result = ((((IOAPIC_NUM_PINS - 1) & 0xff) << 16)
>                | (IOAPIC_VERSION_ID & 0xff));
>          break;
>
> ./virt/kvm/ioapic.h:#define IOAPIC_REG_VERSION 0x01
>
> I hit this as we have on OS that was checking for the number of IRQ pins
> and we were falling into the default case.
>
> Is this a known issue? What's the best way to submit a patch/get this
> committed if it is an accepted bug?
>
> tx
>
> neil