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 --]
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=201007051146.01796.sheng@linux.intel.com \
--to=sheng@linux.intel.com \
--cc=keir.fraser@eu.citrix.com \
--cc=xen-devel@lists.xensource.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.