BUG: fbback doesn't unmap pages on disconnect

BUG: fbback doesn't unmap pages on disconnect

[Vladimir 'φ-coder/phcoder' Serbinenko]

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./tools/qemu-xen-traditional-dir-remote/hw/xenfb.c:

    /*
     * FIXME: qemu can't un-init gfx display (yet?).
     *   Replacing the framebuffer with anonymous shared memory
     *   instead.  This releases the guest pages and keeps qemu happy.
     */
    fb->pixels = mmap(fb->pixels, fb->fbpages * XC_PAGE_SIZE,
                      PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON,
                      -1, 0);
Well it doesn't unmap. There is no unmap on this code path. And since
the mapping is read-write the pages which are supposed to be released,
are now not usable for holding paging table anymore. Can anyone suggest
a workaround to munmap those pages? Could this bug be fixed?


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Re: BUG: fbback doesn't unmap pages on disconnect

[George Dunlap]

CC'ing the relevant maintainers...

On Wed, Dec 18, 2013 at 3:14 PM, Vladimir 'φ-coder/phcoder' Serbinenko
<phcoder@gmail.com> wrote:
> ./tools/qemu-xen-traditional-dir-remote/hw/xenfb.c:
>
>     /*
>      * FIXME: qemu can't un-init gfx display (yet?).
>      *   Replacing the framebuffer with anonymous shared memory
>      *   instead.  This releases the guest pages and keeps qemu happy.
>      */
>     fb->pixels = mmap(fb->pixels, fb->fbpages * XC_PAGE_SIZE,
>                       PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON,
>                       -1, 0);
> Well it doesn't unmap. There is no unmap on this code path. And since
> the mapping is read-write the pages which are supposed to be released,
> are now not usable for holding paging table anymore. Can anyone suggest
> a workaround to munmap those pages? Could this bug be fixed?
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
>

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