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Re: [Qemu-devel] [RFC] Next gen kvm api
From: |
Avi Kivity |
Subject: |
Re: [Qemu-devel] [RFC] Next gen kvm api |
Date: |
Sun, 05 Feb 2012 11:44:43 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111222 Thunderbird/9.0 |
On 02/05/2012 11:37 AM, Gleb Natapov wrote:
> On Thu, Feb 02, 2012 at 06:09:54PM +0200, Avi Kivity wrote:
> > Device model
> > ------------
> > Currently kvm virtualizes or emulates a set of x86 cores, with or
> > without local APICs, a 24-input IOAPIC, a PIC, a PIT, and a number of
> > PCI devices assigned from the host. The API allows emulating the local
> > APICs in userspace.
> >
> > The new API will do away with the IOAPIC/PIC/PIT emulation and defer
> > them to userspace. Note: this may cause a regression for older guests
> > that don't support MSI or kvmclock. Device assignment will be done
> > using VFIO, that is, without direct kvm involvement.
> >
> So are we officially saying that KVM is only for modern guest
> virtualization?
No, but older guests may have reduced performance in some workloads
(e.g. RHEL4 gettimeofday() intensive workloads).
> Also my not so old host kernel uses MSI only for NIC.
> SATA and USB are using IOAPIC (though this is probably more HW related
> than kernel version related).
For devices emulated in userspace, it doesn't matter where the IOAPIC
is. It only matters for kernel provided devices (PIT, assigned devices,
vhost-net).
--
error compiling committee.c: too many arguments to function
- Re: [Qemu-devel] [RFC] Next gen kvm api, (continued)
- Re: [Qemu-devel] [RFC] Next gen kvm api, Anthony Liguori, 2012/02/07
- Re: [Qemu-devel] [RFC] Next gen kvm api, Avi Kivity, 2012/02/07
- Re: [Qemu-devel] [RFC] Next gen kvm api, Jan Kiszka, 2012/02/07
- Re: [Qemu-devel] [RFC] Next gen kvm api, Anthony Liguori, 2012/02/07
- Re: [Qemu-devel] [RFC] Next gen kvm api, Jan Kiszka, 2012/02/07
- Re: [Qemu-devel] [RFC] Next gen kvm api, Avi Kivity, 2012/02/15
- Re: [Qemu-devel] [RFC] Next gen kvm api, Anthony Liguori, 2012/02/07
- Re: [Qemu-devel] [RFC] Next gen kvm api, Avi Kivity, 2012/02/15
- Re: [Qemu-devel] [RFC] Next gen kvm api, Avi Kivity, 2012/02/07
Re: [Qemu-devel] [RFC] Next gen kvm api, Gleb Natapov, 2012/02/05
- Re: [Qemu-devel] [RFC] Next gen kvm api,
Avi Kivity <=
Re: [Qemu-devel] [RFC] Next gen kvm api, Anthony Liguori, 2012/02/05
Re: [Qemu-devel] [RFC] Next gen kvm api, Avi Kivity, 2012/02/06
Re: [Qemu-devel] [RFC] Next gen kvm api, Anthony Liguori, 2012/02/06
Re: [Qemu-devel] [RFC] Next gen kvm api, Avi Kivity, 2012/02/06
Re: [Qemu-devel] [RFC] Next gen kvm api, Anthony Liguori, 2012/02/06
Re: [Qemu-devel] [RFC] Next gen kvm api, Avi Kivity, 2012/02/06