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    SubjectRe: [PATCH v3 00/12] KVM: Add host swap event notifications for PV guest
    On 01/05/2010 10:05 AM, Jun Koi wrote:
    > On Tue, Jan 5, 2010 at 11:12 PM, Gleb Natapov<gleb@redhat.com> wrote:
    >> KVM virtualizes guest memory by means of shadow pages or HW assistance
    >> like NPT/EPT. Not all memory used by a guest is mapped into the guest
    >> address space or even present in a host memory at any given time.
    >> When vcpu tries to access memory page that is not mapped into the guest
    >> address space KVM is notified about it. KVM maps the page into the guest
    >> address space and resumes vcpu execution. If the page is swapped out
    >> from host memory vcpu execution is suspended till the page is not swapped
    >> into the memory again. This is inefficient since vcpu can do other work
    >> (run other task or serve interrupts) while page gets swapped in.
    >>
    >> To overcome this inefficiency this patch series implements "asynchronous
    >> page fault" for paravirtualized KVM guests. If a page that vcpu is
    >> trying to access is swapped out KVM sends an async PF to the vcpu
    >> and continues vcpu execution. Requested page is swapped in by another
    >> thread in parallel. When vcpu gets async PF it puts faulted task to
    >> sleep until "wake up" interrupt is delivered. When the page is brought
    >> to the host memory KVM sends "wake up" interrupt and the guest's task
    >> resumes execution.
    >>
    >
    > Is it true that to make this work, we will need a (PV) kernel driver
    > for each guest OS (Windows, Linux, ...)?

    This patch series contains the guest kernel code for Linux,
    as well as the host side code.

    --
    All rights reversed.


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