From: Sheng Yang <sheng@linux.intel.com>
To: Keir Fraser <keir.fraser@eu.citrix.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: [PATCH] No need to emulate WBINVD when VT-d force snooping feature available
Date: Mon, 5 Jul 2010 11:46:01 +0800 [thread overview]
Message-ID: <201007051146.01796.sheng@linux.intel.com> (raw)
[-- Attachment #1: Type: Text/Plain, Size: 1195 bytes --]
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
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -1064,8 +1064,10 @@
* 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
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2089,6 +2089,9 @@
if ( !has_arch_mmios(current->domain) )
return;
+ if ( iommu_snoop )
+ return;
+
if ( cpu_has_wbinvd_exiting )
on_each_cpu(wbinvd_ipi, NULL, 1);
else
[-- Attachment #2: iommu_snp_wbinvd.patch --]
[-- Type: text/x-patch, Size: 1058 bytes --]
diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -1064,8 +1064,10 @@
* 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
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2089,6 +2089,9 @@
if ( !has_arch_mmios(current->domain) )
return;
+ if ( iommu_snoop )
+ return;
+
if ( cpu_has_wbinvd_exiting )
on_each_cpu(wbinvd_ipi, NULL, 1);
else
[-- Attachment #3: Type: text/plain, Size: 138 bytes --]
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next reply other threads:[~2010-07-05 3:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-05 3:46 Sheng Yang [this message]
2010-07-05 9:36 ` [PATCH] No need to emulate WBINVD when VT-d force snooping feature available Ian Pratt
2010-07-05 10:09 ` Keir Fraser
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