The patch titled
paravirt: iOPL handling for paravirt guests
has been added to the -mm tree. Its filename is
paravirt-iopl-handling-for-paravirt-guests.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: paravirt: iOPL handling for paravirt guests
From: Zachary Amsden <zach@xxxxxxxxxx>
I found a clever way to make the extra IOPL switching invisible to
non-paravirt compiles - since kernel_rpl is statically defined to be zero
there, and only non-zero rpl kernel have a problem restoring IOPL, as popf
does not restore IOPL flags unless run at CPL-0.
Signed-off-by: Zachary Amsden <zach@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Chris Wright <chrisw@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/i386/kernel/process.c | 9 +++++++++
1 files changed, 9 insertions(+)
diff -puN arch/i386/kernel/process.c~paravirt-iopl-handling-for-paravirt-guests arch/i386/kernel/process.c
--- a/arch/i386/kernel/process.c~paravirt-iopl-handling-for-paravirt-guests
+++ a/arch/i386/kernel/process.c
@@ -665,6 +665,15 @@ struct task_struct fastcall * __switch_t
load_TLS(next, cpu);
/*
+ * Restore IOPL if needed. In normal use, the flags restore
+ * in the switch assembly will handle this. But if the kernel
+ * is running virtualized at a non-zero CPL, the popf will
+ * not restore flags, so it must be done in a separate step.
+ */
+ if (get_kernel_rpl() && unlikely(prev->iopl != next->iopl))
+ set_iopl_mask(next->iopl);
+
+ /*
* Now maybe handle debug registers and/or IO bitmaps
*/
if (unlikely((task_thread_info(next_p)->flags & _TIF_WORK_CTXSW)
_
Patches currently in -mm which might be from zach@xxxxxxxxxx are
convert-i386-pda-code-to-use-%fs.patch
convert-i386-pda-code-to-use-%fs-fixes.patch
paravirt-page-allocation-hooks-for-vmi-backend.patch
paravirt-paravirt-cpu-hypercall-batching-mode.patch
paravirt-iopl-handling-for-paravirt-guests.patch
paravirt-smp-boot-hook-for-paravirt.patch
paravirt-vmi-backend-for-paravirt-ops.patch
paravirt-vmi-timer-patches.patch
i386-apic-clean-up-the-apic-code.patch
i386-apic-rework-and-fix-local-apic-calibration.patch
dynticks-i386-prepare-nmi-watchdog.patch
-
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