Re: [Xen-devel] [PATCH] x86 vm_event: reset monitor in vm_event_cleanup_domain()

[Tamas K Lengyel <tamas@xxxxxxxxxxxxx>]

On Wed, Jan 27, 2016 at 12:42 PM, Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx> wrote:

It is currently possible to leave a monitor flag enabled even
after vm_event_cleanup_domain() has been called, potentially
leading to a crash in hvm_msr_write_intercept() and hvm_set_crX()
(when v->arch.vm_event has become NULL, but the corresponding
corresponding v->domain->arch.monitor flag is non-zero).
This patch zeroes out arch.monitor in vm_event_cleanup_domain().

Signed-off-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>

Acked-by: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>

Â

---
Âxen/arch/x86/vm_event.c | 1 +
Â1 file changed, 1 insertion(+)

diff --git a/xen/arch/x86/vm_event.c b/xen/arch/x86/vm_event.c
index 9677ecc..08d678a 100644
--- a/xen/arch/x86/vm_event.c
+++ b/xen/arch/x86/vm_event.c
@@ -56,6 +56,7 @@ void vm_event_cleanup_domain(struct domain *d)
  Â}

  Âd->arch.mem_access_emulate_each_rep = 0;
+Â Â memset(&d->arch.monitor, 0, sizeof(d->arch.monitor));
Â}

Âvoid vm_event_toggle_singlestep(struct domain *d, struct vcpu *v)
--
2.7.0

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