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    SubjectRe: [RFC] Next gen kvm api
    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,

    error compiling committee.c: too many arguments to function

     \ /
      Last update: 2012-02-05 10:47    [W:0.020 / U:6.304 seconds]
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