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Re: [Qemu-devel] QEMU issues on SPARC hosts due to more-than-page-alignm
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From: |
Peter Maydell |
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Subject: |
Re: [Qemu-devel] QEMU issues on SPARC hosts due to more-than-page-alignment requirement for MAP_SHARED|MAP_FIXED... |
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Date: |
Fri, 16 Jun 2017 10:18:47 +0100 |
On 15 June 2017 at 20:13, Laszlo Ersek <address@hidden> wrote:
> If that's not the case, i.e. Linux on SPARC enforces SHMLBA for all
> kinds of mmap() -- which I would call a POSIX conformance bug --,
I'm pretty sure it does: the intention is to avoid violating
h/w cache aliasing constraints so the code enforces the
16k alignment restriction for any MAP_SHARED mapping.
(This is only awkward for MAP_FIXED since otherwise it can
just pick the address to suit its purposes anyway.)
(As an aside I wonder whether any still-used hardware has
the cache aliasing constraints in question :-))
thanks
-- PMM