[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] 32bit PAE PV guest on 64bit hypervisor
Keir Fraser wrote: On 14/04/2009 04:39, "Mukesh Rathor" <mukesh.rathor@xxxxxxxxxx> wrote: .. Implementing clear_fixmap() with set_pte() is not correct, even on native. Since it clears high then low, it temporarily leaves you with a possibly invalid present PTE -- even on native this can cause problems if e.g., the invalid PTE maps uncacheable I/O memory. In our kernel we simply solved this by implementing __set_fixmap() with a hypercall that could update all 64 bits at once. An alternative is indeed to clear low then high. Basically, clearing a pte has to be done the opposite way round to setting a pte. -- Keir Just a quick update, I changed to hypercall and it worked. BTW, I also had to increase the __PHYSICAL_MASK_SHIFT in guest (to 40) as I'm on system with 128GB. With both changes in the 32bit PAE guest, it's doing OK now. Thanks for the help. Mukesh _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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