Messages in this thread | | | Date | Mon, 30 Jan 2012 17:49:46 +0200 | From | Avi Kivity <> | Subject | Re: [PATCH 3/4 V10] Add ioctl for KVMCLOCK_GUEST_STOPPED |
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On 01/30/2012 05:32 PM, Eric B Munson wrote: > > > > Can you point me to the discussion that moved this to be a vm ioctl? In > > general vm ioctls that do things for all vcpus are racy, like here. > > You're accessing variables that are protected by the vcpu mutex, and not > > taking the mutex (nor can you, since it is held while the guest is > > running, unlike most kernel mutexes). > > > > Jan Kiszka suggested that becuase there isn't a use case for notifying > individual vcpus (can vcpu's be paused individually?
They can, though the guest will grind to a halt very soon.
> ) that it makes more sense > to have a vm ioctl. > > http://thread.gmane.org/gmane.comp.emulators.qemu/131624 > > If the per vcpu ioctl is the right choice I can resend those patches.
The races are solvable but I think it's easier in userspace. It's also more flexible, though I don't really see a use for this flexibility.
-- error compiling committee.c: too many arguments to function
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