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    SubjectRe: [PATCH v6 12/12] KVM: indicate readonly access fault
    On 09/12/2012 06:44 PM, Marcelo Tosatti wrote:
    > On Wed, Sep 12, 2012 at 06:34:33PM +0300, Avi Kivity wrote:
    >> On 09/11/2012 05:39 PM, Marcelo Tosatti wrote:
    >> > On Tue, Sep 11, 2012 at 12:18:22PM +0300, Avi Kivity wrote:
    >> >> > The same can happen with slot deletion, for example.
    >> >> >
    >> >> > Userspace (which performed the modification which can result in faults
    >> >> > to non-existant/read-only/.../new-tag memslot), must handle the faults
    >> >> > properly or avoid the possibility for reference to memslot information
    >> >> > from the past.
    >> >> >
    >> >> > I think its worthwhile to add a note about this in the API
    >> >> > documentation: "The user of this interface is responsible for handling
    >> >> > references to stale memslot information, either by handling
    >> >> > exit notifications which reference stale memslot information or not
    >> >> > allowing these notifications to exist by stopping all vcpus in userspace
    >> >> > before performing modifications to the memslots map".
    >> >>
    >> >> Or we can drop the new interface and rely on userspace to perform the
    >> >> lookup under its own locking rules.
    >> >>
    >> >> It's slow, but writes to ROM or ROM/device are rare anyway.
    >> >
    >> > Lookup what information?
    >>
    >> Where to dispatch the write.
    >>
    >> In fact userspace has to do that anyway if it's a ROM/device. There's
    >> no way userspace can guess that unless we pass in the slot number (which
    >> isn't synchronized with anything).
    >
    > Alright, do you prefer the details of this exit to be worked out later,
    > when necessary, then?
    >
    > That is, not merge this particular patch of the series?
    >

    Right. I think it is unneeded.


    --
    error compiling committee.c: too many arguments to function


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