Messages in this thread | | | From | "Liu, Jinsong" <> | Date | Tue, 20 Dec 2011 16:53:56 +0800 | Subject | RE: [Regression, bisected] a3e06bbe8445f57eb949e6474c5a9b30f24d2057: KVM: emulate lapic tsc deadline timer for guest" |
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Alexey Zaytsev wrote: > On Wed, Dec 14, 2011 at 11:37, Alexey Zaytsev > <alexey.zaytsev@nexenta.com> wrote: >> On Mon, Dec 12, 2011 at 10:13, Liu, Jinsong <jinsong.liu@intel.com> >> wrote: >>> Alexey Zaytsev wrote: >>>> Hi. >>>> >>>> After a recent change, qemu --enable-kvm (both 0.15.92 and 1.0) >>>> fails to boot illumos. The OS gets stuck pretty late in the boot >>>> process, without any hints from the guest. MDB (the illumos >>>> kenrnel debugger) failed to clarify the situation at once, the >>>> kernel seems to be stuck idling. I've bisected the problem to >>>> commit a3e06bbe8445f57eb949e6474c5a9b30f24d2057. Please let me >>>> know if you need me to collect any debug information or test any >>>> patches. >>> >>> Alexey, >>> >>> Does illumos use tsc deadline timer? and do you run it at Intel >>> platform? >>> >>> If yes, would you please help me to collect debug information by >>> add some printk points at kvm tsc deadline timer logic? currently I >>> totally have no clue to figure out what the issue root from :) and, >>> would you please check illumos tsc deadline timer logic by confirm >>> whether illumos 1). Enumerate tsc deadline timer capability by >>> CPUID; 2). Enable tsc deadline timer mode by lapic MMIO; 3). Start >>> tsc deadline timer by WRMSR; >> >> I think, here's what's going on. We get into >> kvm_get_lapic_tscdeadline_msr/kvm_set_lapic_tscdeadline_msr, but qemu >> does not use the KVM_CREATE_IRQCHIP ioctl, so we are running without >> vcpu->arch.apic and the functions do nothing. And the Linux guest >> just handles broken tsc a lot better, so it survives. Both guests >> seem to work fine with qemu-kvm, which uses the ioctl. >> > > Hi. Do you need any more info on thins?
Seems illumos works fine w/ qemu-kvm, that's enough. Maybe you need to wait qemu-kvm sync into qemu?
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