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| author | Rusty Russell <rusty@rustcorp.com.au> | 2015-03-24 11:51:39 +1030 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2015-03-24 11:52:08 +1030 |
| commit | 2f921b5bb0511fb698681d8ef35c48be7a9116bf (patch) | |
| tree | e4f07e4d66f47c7af9142bf13e5851a77acec77f /arch/x86/lguest/head_32.S | |
| parent | 7042cb4eb30967b5eb9eeba04907882f04d6b6e5 (diff) | |
| download | linux-2f921b5bb0511fb698681d8ef35c48be7a9116bf.tar.bz2 | |
lguest: suppress interrupts for single insn, not range.
The last patch reduced our interrupt-suppression region to one address,
so simplify the code somewhat.
Also, remove the obsolete undefined instruction ranges and the comment
which refers to lguest_guest.S instead of head_32.S.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'arch/x86/lguest/head_32.S')
| -rw-r--r-- | arch/x86/lguest/head_32.S | 15 |
1 files changed, 6 insertions, 9 deletions
diff --git a/arch/x86/lguest/head_32.S b/arch/x86/lguest/head_32.S index 81678bf0fcb7..d5ae63f5ec5d 100644 --- a/arch/x86/lguest/head_32.S +++ b/arch/x86/lguest/head_32.S @@ -133,9 +133,8 @@ ENTRY(lg_restore_fl) ret /*:*/ -/* These demark the EIP range where host should never deliver interrupts. */ -.global lguest_noirq_start -.global lguest_noirq_end +/* These demark the EIP where host should never deliver interrupts. */ +.global lguest_noirq_iret /*M:004 * When the Host reflects a trap or injects an interrupt into the Guest, it @@ -174,12 +173,11 @@ ENTRY(lg_restore_fl) * * The second is harder: copying eflags to lguest_data.irq_enabled will turn * interrupts on before we're finished, so we could be interrupted before we - * return to userspace or wherever. Our solution to this is to surround the - * code with lguest_noirq_start: and lguest_noirq_end: labels. We tell the + * return to userspace or wherever. Our solution to this is to tell the * Host that it is *never* to interrupt us there, even if interrupts seem to be * enabled. (It's not necessary to protect pop instruction, since - * data gets updated only after it completes, so we end up surrounding - * just one instruction, iret). + * data gets updated only after it completes, so we only need to protect + * one instruction, iret). */ ENTRY(lguest_iret) pushl 2*4(%esp) @@ -190,6 +188,5 @@ ENTRY(lguest_iret) * prefix makes sure we use the stack segment, which is still valid. */ popl %ss:lguest_data+LGUEST_DATA_irq_enabled -lguest_noirq_start: +lguest_noirq_iret: iret -lguest_noirq_end: |