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Re: [Xen-devel] Bug: Windows 2003 fails to install on xen-unstable tip

On 23/04/13 11:25, Jan Beulich wrote:
On 22.04.13 at 17:32, George Dunlap <george.dunlap@xxxxxxxxxxxxx> wrote:
(XEN) pt on: 10 @14fd4b61ef^M
(XEN) B=42 [A:2a B:02 C:50 pt:10/0] @14fd6f73d9^M
(XEN) C=50 pt=10/0 @14fdb032f8^M
(XEN) C=c0 pt=10/6 @14fddabc31^M
(XEN) C=00 pt=10/0 @14fe04d583^M
(XEN) C=c0 pt=10/0 @14feaa9978^M
(XEN) C=00 pt=10/0 @14fed2ae4b^M
(XEN) C=c0 pt=10/0 @14ff98fe90^M
(XEN) C=00 pt=10/0 @14ffc0fbc1^M
(XEN) irq.c:270: Dom1 PCI link 0 changed 5 -> 0^M
(XEN) irq.c:270: Dom1 PCI link 1 changed 10 -> 0^M
(XEN) irq.c:270: Dom1 PCI link 2 changed 11 -> 0^M
(XEN) irq.c:270: Dom1 PCI link 3 changed 5 -> 0^M
(XEN) pt off #105 @15e95c8ff8^M
(XEN) pt irq @15da75fb9c (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15db644b09 (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15dc53074a (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15dd41309b (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15de2f93db (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15df1e6232 (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15e00c3c2f (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15e0faca4c (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15e1e94f41 (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15e2d7b303 (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15e3c61780 (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15e4b4cd99 (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15e5a33c65 (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15e690a53a (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15e77f1d0f (rtc_periodic_interrupt+0x81/0x93)^M
(XEN) pt irq @15e86d876a (rtc_periodic_interrupt+0x81/0x93)^M
So we send IRQs as regularly as we're expected to, but Windows
doesn't even look at REG_C. To me it seems perfectly valid to stop
sending further IRQs in that case.

Perhaps something else is going on -- e.g., Windows is *reading* something different from the RTC, and acting differently in response to that?

It's obviously a quirk in Windows 2003, as XP and Win7 seem to deal with it just fine. Nonetheless, we can't very well just say, "Well, it's a bug in Windows, so go talk to Microsoft". :-)

In any event the time stamps appear to confirm that the respective
second REG_C reads are likely checks at the end of the interrupt
handler in Windows, and that the increased deferral of turning off
the periodic timer didn't make a difference.

Just to double check - could you comment out entirely the first
(normal code, i.e. not the one marked //todo?) "else if" in
rtc_periodic_interrupt() (including its body of course)? I would
expect this to not make a difference, and if so I don't see how
Windows expects to be woken up again (I would guess that
they internally have some gating logic preventing the normal IRQ8
handling to happen, yet of course we don't know what would
reset that state).

In fact, when I comment out that region, then it hangs in the guest BIOS before even attempting to boot the CD.

I took a look at the offending changeset, and unfortunately it seems to have a lot of different changes, so it's not 100% clear which ones are related or not. I'll give it a try anyway. Do you not have boot images of Windows 2003 that you can test yourself?


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