[Xen-changelog] [xen master] xen/arm: flush_tlb_domain: Disable IRQ when flushing TLB of another domain

[patchbot@xxxxxxx]

commit 9bb013c878f2de645bb588938542d936e9bb2e58
Author:     Julien Grall <julien.grall@xxxxxxxxxx>
AuthorDate: Fri Oct 17 17:14:44 2014 +0100
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Mon Oct 20 13:51:27 2014 +0100

    xen/arm: flush_tlb_domain: Disable IRQ when flushing TLB of another domain
    
    When Xen is flushing the TLB for another domain than current, it has to
    switch temporarily to the P2M of this domain. If IRQs are enabled, it may
    be possible to receive an interrupt that requires the use the P2M of the 
current
    domain, or even temporarily switch to another P2M.
    For the former case, the translation would be wrong. For the latter one,
    as the handler would restore the current P2M, Xen would flush the wrong 
domain
    TLB.
    
    Thankfully we don't have such interrupt handler, but it may be necessary
    in the future to do that during when the user asks to dump domain stack via
    a keystroke.
    
    Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    [ ijc -- spelling in the commit log ]
---
 xen/arch/arm/p2m.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 69191b9..76d2369 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -112,17 +112,25 @@ void p2m_restore_state(struct vcpu *n)
 
 void flush_tlb_domain(struct domain *d)
 {
+    unsigned long flags = 0;
+
     /* Update the VTTBR if necessary with the domain d. In this case,
      * it's only necessary to flush TLBs on every CPUs with the current VMID
      * (our domain).
      */
     if ( d != current->domain )
+    {
+        local_irq_save(flags);
         p2m_load_VTTBR(d);
+    }
 
     flush_tlb();
 
     if ( d != current->domain )
+    {
         p2m_load_VTTBR(current->domain);
+        local_irq_restore(flags);
+    }
 }
 
 /*
--
generated by git-patchbot for /home/xen/git/xen.git#master

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