Derek Murray wrote:
> If we let Linux zap the page tables before we unmap the grant reference,
> then it is not possible to unmap the grant reference. The
> unmap_grant_ref hypercall ultimately calls destroy_grant_pte_mapping in
> xen/arch/x86/mm.c, which ensures that the PTE does in fact point to
> Hi Mark,
>
> > Maybe a change to the gntdev userspace API to allow batching
> > of mapping requests?
>
> Something along the lines of the following?
Just like that :-D
When you said "multiple syscalls per mapping" I assumed you meant that we'd
lose the batching you get by doing a mulicall. If
Hi Mark,
> Maybe a change to the gntdev userspace API to allow batching
> of mapping requests?
Something along the lines of the following?
/**
* Memory maps one or more grant references from one or more domains to a
* contiguous local address range. Mappings should be unmapped with
* xc_gnt
> >> It gets better, though. The same hook is used in the version of blktap
> >> in linux-2.6.18-xen (not, as far as I can see, in the sparse tree for
> >> xen-3.1-testing):
> >
> > Oh, I'm thinking more in the direction of killing blktap altogether in
> > favor of a pure userspace implementation o
I take the blame for that one. I added the hook because, if a process
were to die whilst holding one or more grants, there were no hooks that
would make it possible to carry out the grant-unmap. All existing hooks
on either the device or the VMA were called *after* the PTEs were cleared.
It ge
Gerd Hoffmann wrote:
Derek Murray wrote:
I take the blame for that one. I added the hook because, if a process
were to die whilst holding one or more grants, there were no hooks that
would make it possible to carry out the grant-unmap. All existing hooks
on either the device or the VMA were call
Derek Murray wrote:
> I take the blame for that one. I added the hook because, if a process
> were to die whilst holding one or more grants, there were no hooks that
> would make it possible to carry out the grant-unmap. All existing hooks
> on either the device or the VMA were called *after* the P
Stephen C. Tweedie wrote:
> Hi all,
>
> driver domains
Looked at the gntdev (grant table mappings for user space) driver,
noticed that one is not self-contained. It needs a hook for page unmapping:
http://xenbits.xensource.com/xen-3.1-testing.hg?rev/7180d2e61f92
plus an s/ptep_get_and_cle
