[Xen-ia64-devel] [PATCH] fix vmx_vcpu_flush_tlb_all()

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

[IA64] fix vmx_vcpu_flush_tlb_all()

There is a race between vmx_vcpu_flush_tlb_all() and vmx_vcpu_ptc_ga().
__thash_purge_all() can be called without interrupt disabled so that
vmx_vcpu_ptc_ga() may issue ipi to call ptc_ga_remote_func() on that
pCPU during __thash_purge_all() is executing. And both of the functions
manipulate vcpu->arch.vtlb.
To avoid the race, mask interrupts in __thash_purge_all().

Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>

diff -r b5c925071c07 xen/arch/ia64/vmx/vtlb.c
--- a/xen/arch/ia64/vmx/vtlb.c  Thu Jul 31 19:01:03 2008 +0900
+++ b/xen/arch/ia64/vmx/vtlb.c  Thu Jul 31 20:14:47 2008 +0900
@@ -626,9 +626,14 @@
 static void __thash_purge_all(void *arg)
 {
     struct vcpu *v = arg;
+    unsigned long flags;
 
     BUG_ON(vcpu_runnable(v) || v->is_running);
+
+    /* we are racing with vmx_vcpu_ptc_ga() */
+    local_irq_save(flags);
     thash_purge_all(v);
+    local_irq_restore(flags);
 }
 
 void vmx_vcpu_flush_vtlb_all(VCPU *v)

-- 
yamahata

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