From: Paolo Bonzini <pbonzini@redhat.com>
To: unlisted-recipients:; (no To-header on input)
Cc: Jan Kiszka <jan.kiszka@web.de>,
Arthur Chunqi Li <yzt356@gmail.com>,
kvm@vger.kernel.org, gleb@redhat.com, "Zhang,
Yang Z" <yang.z.zhang@intel.com>
Subject: Re: [PATCH v5] KVM: nVMX: Fully support of nested VMX preemption timer
Date: Thu, 26 Sep 2013 22:44:45 +0200 [thread overview]
Message-ID: <52449CBD.4010603@redhat.com> (raw)
In-Reply-To: <52447335.9090601@redhat.com>
Il 26/09/2013 19:47, Paolo Bonzini ha scritto:
>
> If I only apply this hunk, which disables the preemption timer while
> in L1:
>
> @@ -8396,6 +8375,8 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu)
>
> load_vmcs12_host_state(vcpu, vmcs12);
>
> + vmcs_write32(PIN_BASED_VM_EXEC_CONTROL, vmx_pin_based_exec_ctrl(vmx));
> +
> /* Update TSC_OFFSET if TSC was changed while L2 ran */
> vmcs_write64(TSC_OFFSET, vmx->nested.vmcs01_tsc_offset);
>
> then the testcase works for somewhat larger values of the preemption timer
> (up to ~1500000 TSC cycles), but then fails.
I mean if I apply it on top of current kvm/next, without Arthur's patch.
If I apply the hunk on top of Arthur's patch nothing changes and the
timer testcase starts breaking around ~65000 TSC cycles.
It is a bit problematic that adding printks changes something, so that
the test starts passing. I haven't tried tracepoints yet.
Jan, which L1 is using the preemption timer? Any reason why you added
it? I wonder if it isn't better to revert it, since it is quite broken.
Paolo
next prev parent reply other threads:[~2013-09-26 20:44 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-16 8:11 [PATCH v5] KVM: nVMX: Fully support of nested VMX preemption timer Arthur Chunqi Li
2013-09-22 7:47 ` Gleb Natapov
2013-09-25 13:58 ` Paolo Bonzini
2013-09-26 15:04 ` Paolo Bonzini
2013-09-26 17:19 ` Jan Kiszka
2013-09-26 17:47 ` Paolo Bonzini
2013-09-26 20:44 ` Paolo Bonzini [this message]
2013-09-27 6:37 ` Jan Kiszka
2013-09-29 16:24 ` Jan Kiszka
2013-09-29 11:30 ` Gleb Natapov
2013-09-30 9:08 ` Jan Kiszka
2013-10-02 18:47 ` Jan Kiszka
2013-10-10 16:12 ` Jan Kiszka
2013-10-10 16:20 ` Paolo Bonzini
2013-10-25 9:56 ` Paolo Bonzini
2013-10-25 9:59 ` Jan Kiszka
2013-10-11 8:17 ` Arthur Chunqi Li
2013-10-03 8:09 ` Paolo Bonzini
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