lkml.org 
[lkml]   [2016]   [Jul]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v3 2/2] KVM: nVMX: Fix preemption timer bit set in vmcs02 even if L1 doesn't enable it
From
Date


On 07/07/2016 05:46, Wanpeng Li wrote:
> From: Wanpeng Li <wanpeng.li@hotmail.com>
>
> We will go to vcpu_run() loop after L0 emulates VMRESUME which incurs
> kvm_sched_out and kvm_sched_in operations since cond_resched() will be
> called once need resched. Preemption timer will be reprogrammed if vCPU
> is scheduled to a different pCPU. Then the preemption timer bit of vmcs02
> will be set if L0 enable preemption timer to run L1 even if L1 doesn't
> enable preemption timer to run L2.
>
> This patch fix it by don't reprogram preemption timer of vmcs02 if L1's
> vCPU is scheduled on diffent pCPU when we are in the way to vmresume
> nested guest.

Again, this is wrong. There is no reason why L1's APIC timer cannot be
emulated through the vmcs12's preemption timer setting. The only issue
is getting the pin-based execution controls right.

Paolo

\
 
 \ /
  Last update: 2016-07-07 10:41    [W:0.192 / U:0.408 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site