This is a note to let you know that I've just added the patch titled
KVM: VMX: Fix kvm_set_shared_msr() called in preemptible context
to the 3.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-vmx-fix-kvm_set_shared_msr-called-in-preemptible-context.patch
and it can be found in the queue-3.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From [email protected] Wed May 9 06:14:31 2012
From: Avi Kivity <[email protected]>
Date: Wed, 9 May 2012 16:10:46 +0300
Subject: KVM: VMX: Fix kvm_set_shared_msr() called in preemptible context
To: [email protected]
Cc: Marcelo Tosatti <[email protected]>, [email protected]
Message-ID: <[email protected]>
From: Avi Kivity <[email protected]>
(cherry picked from commit 2225fd56049643c1a7d645c0ce9d499d43c7974e)
kvm_set_shared_msr() may not be called in preemptible context,
but vmx_set_msr() does so:
BUG: using smp_processor_id() in preemptible [00000000] code: qemu-kvm/22713
caller is kvm_set_shared_msr+0x32/0xa0 [kvm]
Pid: 22713, comm: qemu-kvm Not tainted 3.4.0-rc3+ #39
Call Trace:
[<ffffffff8131fa82>] debug_smp_processor_id+0xe2/0x100
[<ffffffffa0328ae2>] kvm_set_shared_msr+0x32/0xa0 [kvm]
[<ffffffffa03a103b>] vmx_set_msr+0x28b/0x2d0 [kvm_intel]
...
Making kvm_set_shared_msr() work in preemptible is cleaner, but
it's used in the fast path. Making two variants is overkill, so
this patch just disables preemption around the call.
Reported-by: Dave Jones <[email protected]>
Signed-off-by: Avi Kivity <[email protected]>
Signed-off-by: Marcelo Tosatti <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/kvm/vmx.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2219,9 +2219,12 @@ static int vmx_set_msr(struct kvm_vcpu *
msr = find_msr_entry(vmx, msr_index);
if (msr) {
msr->data = data;
- if (msr - vmx->guest_msrs < vmx->save_nmsrs)
+ if (msr - vmx->guest_msrs < vmx->save_nmsrs) {
+ preempt_disable();
kvm_set_shared_msr(msr->index, msr->data,
msr->mask);
+ preempt_enable();
+ }
break;
}
ret = kvm_set_msr_common(vcpu, msr_index, data);
Patches currently in stable-queue which might be from [email protected] are
queue-3.3/kvm-s390-do-store-status-after-handling-stop_on_stop-bit.patch
queue-3.3/kvm-nvmx-fix-erroneous-exception-bitmap-check.patch
queue-3.3/kvm-s390-sanitize-fpc-registers-for-kvm_set_fpu.patch
queue-3.3/kvm-x86-emulator-correctly-mask-pmc-index-bits-in-rdpmc-instruction-emulation.patch
queue-3.3/kvm-mmu_notifier-flush-tlbs-before-releasing-mmu_lock.patch
queue-3.3/kvm-vmx-fix-kvm_set_shared_msr-called-in-preemptible-context.patch
queue-3.3/kvm-vmx-vmx_set_cr0-expects-kvm-srcu-locked.patch
queue-3.3/kvm-ensure-all-vcpus-are-consistent-with-in-kernel-irqchip-settings.patch
queue-3.3/kvm-fix-write-protection-race-during-dirty-logging.patch
queue-3.3/kvm-lock-slots_lock-around-device-assignment.patch
queue-3.3/kvm-vmx-fix-delayed-load-of-shared-msrs.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
