From: Peter Zijlstra <peterz@infradead.org>
To: Wanpeng Li <kernellwp@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>,
linux-s390 <linux-s390@vger.kernel.org>,
Davidlohr Bueso <dave@stgolabs.net>,
mpe@ellerman.id.au, boqun.feng@gmail.com, will.deacon@arm.com,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Waiman Long <waiman.long@hpe.com>,
virtualization@lists.linux-foundation.org,
Ingo Molnar <mingo@redhat.com>, Paul Mackerras <paulus@samba.org>,
benh@kernel.crashing.org, schwidefsky@de.ibm.com,
Paul McKenney <paulmck@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org, kvm <kvm@vger.kernel.org>
Subject: Re: [PATCH v2 0/4] implement vcpu preempted check
Date: Thu, 7 Jul 2016 13:15:54 +0200 [thread overview]
Message-ID: <20160707111554.GV30921@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CANRm+CxKVqrFB-cRPEvmUamZ5Y8cOGe3pyc0LMJy0t9_jo+i0Q@mail.gmail.com>
On Thu, Jul 07, 2016 at 06:27:26PM +0800, Wanpeng Li wrote:
> In addition, I see xen's vcpu_runstate_info::state is updated during
> schedule, so I think I can do this similarly through kvm preemption
> notifier. IIUC, xen hypervisor has VCPUOP_get_runstate_info hypercall
> implemention, so the desired interface can be implemented if they add
> hypercall callsite in domU. I can add hypercall to kvm similarly.
So I suspect Xen has the page its writing to pinned in memory; so that a
write to it is guaranteed to not fault.
Otherwise I cannot see this working.
That is part of the larger surgery required for KVM steal time to get
'fixed'. Currently that steal time stuff uses kvm_write_guest_cached()
which appears to be able to fault in guest pages.
Or I'm not reading this stuff right; which is entirely possible.
next prev parent reply other threads:[~2016-07-07 11:16 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-28 14:43 [PATCH v2 0/4] implement vcpu preempted check Pan Xinhui
2016-06-28 14:43 ` [PATCH v2 1/4] kernel/sched: introduce vcpu preempted check interface Pan Xinhui
2016-06-28 14:43 ` [PATCH v2 2/4] powerpc/spinlock: support vcpu preempted check Pan Xinhui
2016-07-05 9:57 ` Wanpeng Li
2016-07-06 4:58 ` xinhui
2016-07-06 6:46 ` Wanpeng Li
2016-07-06 7:58 ` Peter Zijlstra
2016-07-06 8:32 ` Wanpeng Li
2016-07-06 10:18 ` xinhui
2016-07-06 10:54 ` Balbir Singh
2016-07-15 15:35 ` Pan Xinhui
2016-06-28 14:43 ` [PATCH v2 3/4] locking/osq: Drop the overload of osq_lock() Pan Xinhui
2016-06-28 14:43 ` [PATCH v2 4/4] kernel/locking: Drop the overload of {mutex,rwsem}_spin_on_owner Pan Xinhui
2016-07-06 6:52 ` [PATCH v2 0/4] implement vcpu preempted check Peter Zijlstra
2016-07-06 7:47 ` Juergen Gross
2016-07-06 8:19 ` Peter Zijlstra
2016-07-06 8:38 ` Juergen Gross
2016-07-06 12:44 ` Paolo Bonzini
2016-07-06 16:56 ` Christian Borntraeger
2016-07-06 10:05 ` xinhui
2016-07-06 10:44 ` Paolo Bonzini
2016-07-06 11:59 ` Peter Zijlstra
2016-07-06 12:08 ` Wanpeng Li
2016-07-06 12:28 ` Paolo Bonzini
2016-07-06 13:03 ` Wanpeng Li
2016-07-07 8:48 ` Wanpeng Li
2016-07-07 9:42 ` Peter Zijlstra
2016-07-07 10:12 ` Wanpeng Li
2016-07-07 10:27 ` Wanpeng Li
2016-07-07 11:15 ` Peter Zijlstra [this message]
2016-07-07 11:08 ` Peter Zijlstra
2016-07-07 11:09 ` Peter Zijlstra
2016-07-07 11:21 ` Peter Zijlstra
2016-07-11 15:10 ` Waiman Long
2016-07-12 4:16 ` Juergen Gross
2016-07-12 18:16 ` Waiman Long
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