[Xen-changelog] [xen-unstable] [VMX] Fix use of VMCLEAR a little: no need if not active on any CPU.

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID e6ec0eeabf771ad92c9100310d2a7c522750a5ed
# Parent  dab24595e52989a5c23471cdb9908e38b2d087b9
[VMX] Fix use of VMCLEAR a little: no need if not active on any CPU.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmcs.c |   17 +++++++++++------
 1 files changed, 11 insertions(+), 6 deletions(-)

diff -r dab24595e529 -r e6ec0eeabf77 xen/arch/x86/hvm/vmx/vmcs.c
--- a/xen/arch/x86/hvm/vmx/vmcs.c       Thu Jun 22 15:10:48 2006 +0100
+++ b/xen/arch/x86/hvm/vmx/vmcs.c       Thu Jun 22 15:25:18 2006 +0100
@@ -74,12 +74,15 @@ static void __vmx_clear_vmcs(void *info)
 
 static void vmx_clear_vmcs(struct vcpu *v)
 {
-    unsigned int cpu = v->arch.hvm_vmx.active_cpu;
-
-    if ( (cpu == -1) || (cpu == smp_processor_id()) )
-        __vmx_clear_vmcs(v);
-    else
-        on_selected_cpus(cpumask_of_cpu(cpu), __vmx_clear_vmcs, v, 1, 1);
+    int cpu = v->arch.hvm_vmx.active_cpu;
+
+    if ( cpu == -1 )
+        return;
+
+    if ( cpu == smp_processor_id() )
+        return __vmx_clear_vmcs(v);
+
+    on_selected_cpus(cpumask_of_cpu(cpu), __vmx_clear_vmcs, v, 1, 1);
 }
 
 static void vmx_load_vmcs(struct vcpu *v)
@@ -97,6 +100,8 @@ void vmx_vmcs_enter(struct vcpu *v)
      *     context initialisation.
      *  2. VMPTRLD as soon as we context-switch to a HVM VCPU.
      *  3. VMCS destruction needs to happen later (from domain_destroy()).
+     * We can relax this a bit if a paused VCPU always commits its
+     * architectural state to a software structure.
      */
     if ( v == current )
         return;

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