linux

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Jeremy Fitzhardinge 9f79991d41 xen: deal with stale cr3 values when unpinning pagetables

When a pagetable is no longer in use, it must be unpinned so that its
pages can be freed.  However, this is only possible if there are no
stray uses of the pagetable.  The code currently deals with all the
usual cases, but there's a rare case where a vcpu is changing cr3, but
is doing so lazily, and the change hasn't actually happened by the time
the pagetable is unpinned, even though it appears to have been completed.

This change adds a second per-cpu cr3 variable - xen_current_cr3 -
which tracks the actual state of the vcpu cr3.  It is only updated once
the actual hypercall to set cr3 has been completed.  Other processors
wishing to unpin a pagetable can check other vcpu's xen_current_cr3
values to see if any cross-cpu IPIs are needed to clean things up.

[ Stable folks: 2.6.23 bugfix ]

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Stable Kernel <stable@kernel.org>

2007-10-16 11:51:30 -07:00

boot

x86_64: move kernel

2007-10-11 11:17:24 +02:00

crypto

x86_64: move crypto

2007-10-11 11:17:03 +02:00

ia32

i386/x86_64: move headers to include/asm-x86

2007-10-11 11:20:03 +02:00

kernel

paravirt: clean up lazy mode handling