From: Alexander Graf <agraf@suse.de>
To: Paul Mackerras <paulus@samba.org>,
kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Subject: Re: [PATCH 07/23] KVM: PPC: Book3S: Allow reuse of vCPU object
Date: Fri, 20 Mar 2015 12:01:32 +0100 [thread overview]
Message-ID: <550BFE0C.2040006@suse.de> (raw)
In-Reply-To: <1426844400-12017-8-git-send-email-paulus@samba.org>
On 20.03.15 10:39, Paul Mackerras wrote:
> From: Bharata B Rao <bharata@linux.vnet.ibm.com>
>
> Since KVM isn't equipped to handle closure of vcpu fd from userspace(QEMU)
> correctly, certain work arounds have to be employed to allow reuse of
> vcpu array slot in KVM during cpu hot plug/unplug from guest. One such
> proposed workaround is to park the vcpu fd in userspace during cpu unplug
> and reuse it later during next hotplug.
>
> More details can be found here:
> KVM: https://www.mail-archive.com/kvm@vger.kernel.org/msg102839.html
> QEMU: http://lists.gnu.org/archive/html/qemu-devel/2014-12/msg00859.html
>
> In order to support this workaround with PowerPC KVM, don't create or
> initialize ICP if the vCPU is found to be already associated with an ICP.
>
> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
> Signed-off-by: Paul Mackerras <paulus@samba.org>
This probably makes some sense, but please make sure that user space has
some way to figure out whether hotplug works at all.
Also Paul, for patches that you pick up from others, I'd prefer if they
send the patches to the ML themselves first and you pick them up from
there then. That way we give everyone the same treatment.
Alex
next prev parent reply other threads:[~2015-03-20 11:01 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-20 9:39 [PATCH 00/23] Bug fixes and improvements for HV KVM Paul Mackerras
2015-03-20 9:39 ` [PATCH 01/23] KVM: PPC: Book3S HV: Fix spinlock/mutex ordering issue in kvmppc_set_lpcr() Paul Mackerras
2015-03-20 9:39 ` [PATCH 02/23] KVM: PPC: Book3S HV: Endian fix for accessing VPA yield count Paul Mackerras
2015-03-20 9:39 ` [PATCH 03/23] KVM: PPC: Book3S HV: Fix instruction emulation Paul Mackerras
2015-03-20 9:39 ` [PATCH 04/23] KVM: PPC: Book3S HV: Add fast real-mode H_RANDOM implementation Paul Mackerras
2015-03-20 9:39 ` [PATCH 05/23] KVM: PPC: Book3S HV: Remove RMA-related variables from code Paul Mackerras
2015-03-20 9:39 ` [PATCH 06/23] KVM: PPC: Book3S HV: Add helpers for lock/unlock hpte Paul Mackerras
2015-03-20 9:39 ` [PATCH 07/23] KVM: PPC: Book3S: Allow reuse of vCPU object Paul Mackerras
2015-03-20 11:01 ` Alexander Graf [this message]
2015-03-20 11:26 ` Paul Mackerras
2015-03-20 11:34 ` Alexander Graf
2015-03-20 15:51 ` Bharata B Rao
2015-03-21 14:58 ` Alexander Graf
2015-03-23 7:50 ` Bharata B Rao
2015-03-23 8:31 ` Alexander Graf
2015-03-20 9:39 ` [PATCH 08/23] KVM: PPC: Book3S HV: Add guest->host real mode completion counters Paul Mackerras
2015-03-20 9:39 ` [PATCH 09/23] KVM: PPC: Book3S HV: Convert ICS mutex lock to spin lock Paul Mackerras
2015-03-20 9:39 ` [PATCH 10/23] KVM: PPC: Book3S HV: Move virtual mode ICP functions to real-mode Paul Mackerras
2015-03-20 9:39 ` [PATCH 11/23] KVM: PPC: Book3S HV: Add ICP real mode counters Paul Mackerras
2015-03-20 9:39 ` [PATCH 12/23] KVM: PPC: Book3S HV: Create debugfs file for each guest's HPT Paul Mackerras
2015-03-20 11:20 ` Alexander Graf
2015-03-20 9:39 ` [PATCH 13/23] KVM: PPC: Book3S HV: Accumulate timing information for real-mode code Paul Mackerras
2015-03-20 11:15 ` Alexander Graf
2015-03-20 11:25 ` Paul Mackerras
2015-03-20 11:35 ` Alexander Graf
2015-03-22 22:57 ` Paul Mackerras
2015-03-20 9:39 ` [PATCH 14/23] KVM: PPC: Book3S HV: Simplify handling of VCPUs that need a VPA update Paul Mackerras
2015-03-20 9:39 ` [PATCH 15/23] KVM: PPC: Book3S HV: Minor cleanups Paul Mackerras
2015-03-20 9:39 ` [PATCH 16/23] KVM: PPC: Book3S HV: Move vcore preemption point up into kvmppc_run_vcpu Paul Mackerras
2015-03-20 9:39 ` [PATCH 17/23] KVM: PPC: Book3S HV: Get rid of vcore nap_count and n_woken Paul Mackerras
2015-03-20 9:39 ` [PATCH 18/23] KVM: PPC: Book3S HV: Don't wake thread with no vcpu on guest IPI Paul Mackerras
2015-03-20 9:39 ` [PATCH 19/23] KVM: PPC: Book3S HV: Use decrementer to wake napping threads Paul Mackerras
2015-03-20 9:39 ` [PATCH 20/23] KVM: PPC: Book3S HV: Use msgsnd for signalling threads on POWER8 Paul Mackerras
2015-03-20 11:28 ` Alexander Graf
2015-03-23 0:44 ` Paul Mackerras
2015-03-20 9:39 ` [PATCH 21/23] KVM: PPC: Book3S HV: Streamline guest entry and exit Paul Mackerras
2015-03-20 9:39 ` [PATCH 22/23] KVM: PPC: Book3S HV: Use bitmap of active threads rather than count Paul Mackerras
2015-03-20 9:40 ` [PATCH 23/23] KVM: PPC: Book3S HV: Translate kvmhv_commence_exit to C Paul Mackerras
2015-03-20 10:45 ` [PATCH 00/23] Bug fixes and improvements for HV KVM Alexander Graf
2015-03-20 11:36 ` Alexander Graf
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