From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH 3/5] KVM: add KVM_USER_EXIT vm ioctl for userspace exit
Date: Wed, 5 Aug 2015 15:34:43 +0200 [thread overview]
Message-ID: <20150805133442.GA31952@potion.brq.redhat.com> (raw)
In-Reply-To: <55C20FD2.8020607@redhat.com>
2015-08-05 15:29+0200, Paolo Bonzini:
> On 05/08/2015 15:21, Radim Krčmář wrote:
>> + kvm_for_each_vcpu(idx, vcpu, kvm)
>> + if (vcpu->vcpu_id == vcpu_id) {
>> + kvm_make_request(KVM_REQ_EXIT, vcpu);
>> + kvm_vcpu_kick(vcpu);
>> +
>> + return 0;
>> + }
>> +
>
> Why not a vcpu ioctl? kvm_for_each_vcpu can become pretty expensive if
> you have a few dozen VCPUs.
Yeah, it will be slow, the only bright side is low frequency of calls.
vcpu ioctl should only be issued by the vcpu thread so it would
significantly limit use.
next prev parent reply other threads:[~2015-08-05 13:34 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-05 13:21 [PATCH 0/5] KVM: optimize userspace exits with a new ioctl Radim Krčmář
2015-08-05 13:21 ` [PATCH 1/5] KVM: add kvm_has_request wrapper Radim Krčmář
2015-08-05 13:21 ` [PATCH 2/5] KVM: add KVM_REQ_EXIT request for userspace exit Radim Krčmář
2015-08-05 13:21 ` [PATCH 3/5] KVM: add KVM_USER_EXIT vm ioctl " Radim Krčmář
2015-08-05 13:29 ` Paolo Bonzini
2015-08-05 13:34 ` Radim Krčmář [this message]
2015-08-05 13:38 ` Paolo Bonzini
2015-08-05 13:48 ` Radim Krčmář
2015-08-05 13:21 ` [PATCH 4/5] KVM: optimize common cases in KVM_USER_EXIT Radim Krčmář
2015-08-05 13:21 ` [PATCH 5/5] KVM: x86: add request_exits debug counter Radim Krčmář
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