On 2012-01-27 21:48, Anthony Liguori wrote:
> On 01/17/2012 12:27 PM, Eric B Munson wrote:
>> Often when a guest is stopped from the qemu console, it will report
>> spurious
>> soft lockup warnings on resume. There are kernel patches being
>> discussed that
>> will give the host the ability to tell the guest that it is being
>> stopped and
>> should ignore the soft lockup warning that generates. This patch uses
>> the qemu
>> Notifier system to tell the guest it is about to be stopped.
>>
>> Signed-off-by: Eric B Munson<emunson@xxxxxxxxx>
>>
>> Cc: Avi Kivity<avi@xxxxxxxxxx>
>> Cc: Marcelo Tosatti<mtosatti@xxxxxxxxxx>
>> Cc: Jan Kiszka<jan.kiszka@xxxxxxxxxxx>
>> Cc: ryanh@xxxxxxxxxxxxxxxxxx
>> Cc: aliguori@xxxxxxxxxx
>> Cc: kvm@xxxxxxxxxxxxxxx
>> ---
>> Changes from V6:
>> Remove unnecessary include
>>
>> Changes from V5:
>> KVM_GUEST_PAUSED is now a per vm ioctl instead of per vcpu
>>
>> Changes from V4:
>> Test if the guest paused capability is available before use
>>
>> Changes from V3:
>> Collapse new state change notification function into existsing
>> function.
>> Correct whitespace issues
>> Change ioctl name to KVMCLOCK_GUEST_PAUSED
>> Use for loop to iterate vpcu's
>>
>> Changes from V2:
>> Move ioctl into hw/kvmclock.c so as other arches can use it as it is
>> implemented
>>
>> Changes from V1:
>> Remove unnecessary encapsulating function
>>
>> hw/kvmclock.c | 11 +++++++++++
>> 1 files changed, 11 insertions(+), 0 deletions(-)
>>
>> diff --git a/hw/kvmclock.c b/hw/kvmclock.c
>> index 3b9fb20..ad79f52 100644
>> --- a/hw/kvmclock.c
>> +++ b/hw/kvmclock.c
>> @@ -64,10 +64,21 @@ static int kvmclock_post_load(void *opaque, int
>> version_id)
>> static void kvmclock_vm_state_change(void *opaque, int running,
>> RunState state)
>> {
>> + int ret;
>> KVMClockState *s = opaque;
>> + int cap_guest_paused = kvm_check_extension(kvm_state,
>> KVM_CAP_GUEST_PAUSED);
>>
>> if (running) {
>> s->clock_valid = false;
>> +
>> + if (!cap_guest_paused) {
>> + return;
>> + }
>> +
>> + ret = kvm_vm_ioctl(kvm_state, KVMCLOCK_GUEST_PAUSED, 0);
>> + if (ret) {
>> + fprintf(stderr, "kvmclock_vm_state_change: %s\n",
>> strerror(-ret));
>> + }
>> }
>> }
>
>
> This change looks harmless enough.
Yep, but needs to be redirected after the file renaming in upstream.
> What's the state of the kernel
> bits? I would expect this through uq/master.
Kernel bits aren't merged yet. And the kernel headers will have to be
updated in a previous step.
BTW, this series [1] would be nice to have. Dunno if there is a pull
planned, but anyone trying to extend the KVM interface current runs
against this.
Jan
[1] http://thread.gmane.org/gmane.comp.emulators.qemu/132962
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