From: Keir Fraser <keir.fraser@citrix.com>
Date: Mon, 5 Jul 2010 07:28:08 +0000 (+0100)
Subject: VT-d: No need to emulate WBINVD when force snooping feature available
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~11842
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=34b9ec52897ea6fdbedc695ed7d42242d75f4e27;p=xen.git

VT-d: No need to emulate WBINVD when force snooping feature available

There is no cache coherency issue if VT-d engine's force snooping
feature available.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
---

diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index f03399d222..c83ecab69e 100644
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -1064,8 +1064,10 @@ void vmx_do_resume(struct vcpu *v)
          *  1: flushing cache (wbinvd) when the guest is scheduled out if
          *     there is no wbinvd exit, or
          *  2: execute wbinvd on all dirty pCPUs when guest wbinvd exits.
+         * If VT-d engine can force snooping, we don't need to do these.
          */
-        if ( has_arch_pdevs(v->domain) && !cpu_has_wbinvd_exiting )
+        if ( has_arch_pdevs(v->domain) && !iommu_snoop
+                && !cpu_has_wbinvd_exiting )
         {
             int cpu = v->arch.hvm_vmx.active_cpu;
             if ( cpu != -1 )
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 36521d7695..626693ba52 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2089,6 +2089,9 @@ static void vmx_wbinvd_intercept(void)
     if ( !has_arch_mmios(current->domain) )
         return;
 
+    if ( iommu_snoop )
+        return;
+
     if ( cpu_has_wbinvd_exiting )
         on_each_cpu(wbinvd_ipi, NULL, 1);
     else