[Xen-changelog] [xen-unstable] [HVM][VMX] Fix for CR8 acceleration on 64bit guest.

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

# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxx
# Node ID 2801a14d169acbc09006842614f776a8636819a0
# Parent  697b0203e68fd5b54944ba947c3e3b8d78fae88d
[HVM][VMX] Fix for CR8 acceleration on 64bit guest.

For current CR8 acceleration, we do not call update_tpr_threshold() at
every VMEXIT. But at some situations, we cannot inject guest
interrupts in time. And at some critical time, it will bring up a blue
screen to 64bit Windows guest.

Now, we select to call update_tpr_threshold() at very VMEXIT
time. It's safe, and we do not see clear performance downgrade so
far.

Signed-off-by: Xiaohui Xin xiaohui.xin@xxxxxxxxx
---
 xen/arch/x86/hvm/vlapic.c        |    9 ---------
 xen/arch/x86/hvm/vmx/io.c        |    8 +-------
 xen/arch/x86/hvm/vmx/vmx.c       |    1 -
 xen/include/asm-x86/hvm/vlapic.h |    1 -
 4 files changed, 1 insertion(+), 18 deletions(-)

diff -r 697b0203e68f -r 2801a14d169a xen/arch/x86/hvm/vlapic.c
--- a/xen/arch/x86/hvm/vlapic.c Fri Dec 01 09:28:14 2006 +0000
+++ b/xen/arch/x86/hvm/vlapic.c Fri Dec 01 09:48:18 2006 +0000
@@ -119,19 +119,16 @@ static int vlapic_find_highest_vector(u3
 
 static int vlapic_test_and_set_irr(int vector, struct vlapic *vlapic)
 {
-    vlapic->flush_tpr_threshold = 1;
     return vlapic_test_and_set_vector(vector, vlapic->regs + APIC_IRR);
 }
 
 static void vlapic_set_irr(int vector, struct vlapic *vlapic)
 {
-    vlapic->flush_tpr_threshold = 1;
     vlapic_set_vector(vector, vlapic->regs + APIC_IRR);
 }
 
 static void vlapic_clear_irr(int vector, struct vlapic *vlapic)
 {
-    vlapic->flush_tpr_threshold = 1;
     vlapic_clear_vector(vector, vlapic->regs + APIC_IRR);
 }
 
@@ -634,7 +631,6 @@ static void vlapic_write(struct vcpu *v,
     {
     case APIC_TASKPRI:
         vlapic_set_reg(vlapic, APIC_TASKPRI, val & 0xff);
-        vlapic->flush_tpr_threshold = 1;
         break;
 
     case APIC_EOI:
@@ -667,10 +663,7 @@ static void vlapic_write(struct vcpu *v,
             }
         }
         else
-        {
             vlapic->disabled &= ~VLAPIC_SW_DISABLED;
-            vlapic->flush_tpr_threshold = 1;
-        }
         break;
 
     case APIC_ESR:
@@ -925,8 +918,6 @@ static int vlapic_reset(struct vlapic *v
     vlapic_set_reg(vlapic, APIC_SPIV, 0xff);
     vlapic->disabled |= VLAPIC_SW_DISABLED;
 
-    vlapic->flush_tpr_threshold = 1;
-
     return 1;
 }
 
diff -r 697b0203e68f -r 2801a14d169a xen/arch/x86/hvm/vmx/io.c
--- a/xen/arch/x86/hvm/vmx/io.c Fri Dec 01 09:28:14 2006 +0000
+++ b/xen/arch/x86/hvm/vmx/io.c Fri Dec 01 09:48:18 2006 +0000
@@ -71,10 +71,6 @@ static void update_tpr_threshold(struct 
 {
     int max_irr, tpr;
 
-    /* Clear the work-to-do flag /then/ do the work. */
-    vlapic->flush_tpr_threshold = 0;
-    mb();
-
     if ( !vlapic_enabled(vlapic) || 
          ((max_irr = vlapic_find_highest_irr(vlapic)) == -1) )
     {
@@ -95,7 +91,6 @@ asmlinkage void vmx_intr_assist(void)
     int highest_vector;
     unsigned long eflags;
     struct vcpu *v = current;
-    struct vlapic *vlapic = vcpu_vlapic(v);
     struct hvm_domain *plat=&v->domain->arch.hvm_domain;
     struct periodic_time *pt = &plat->pl_time.periodic_tm;
     unsigned int idtv_info_field;
@@ -110,8 +105,7 @@ asmlinkage void vmx_intr_assist(void)
 
     hvm_set_callback_irq_level();
 
-    if ( vlapic->flush_tpr_threshold )
-        update_tpr_threshold(vlapic);
+    update_tpr_threshold(vcpu_vlapic(v));
 
     has_ext_irq = cpu_has_pending_irq(v);
 
diff -r 697b0203e68f -r 2801a14d169a xen/arch/x86/hvm/vmx/vmx.c
--- a/xen/arch/x86/hvm/vmx/vmx.c        Fri Dec 01 09:28:14 2006 +0000
+++ b/xen/arch/x86/hvm/vmx/vmx.c        Fri Dec 01 09:48:18 2006 +0000
@@ -2500,7 +2500,6 @@ asmlinkage void vmx_vmexit_handler(struc
         break;
 
     case EXIT_REASON_TPR_BELOW_THRESHOLD:
-        vcpu_vlapic(v)->flush_tpr_threshold = 1;
         break;
 
     default:
diff -r 697b0203e68f -r 2801a14d169a xen/include/asm-x86/hvm/vlapic.h
--- a/xen/include/asm-x86/hvm/vlapic.h  Fri Dec 01 09:28:14 2006 +0000
+++ b/xen/include/asm-x86/hvm/vlapic.h  Fri Dec 01 09:48:18 2006 +0000
@@ -54,7 +54,6 @@ struct vlapic {
     uint32_t           timer_divisor;
     struct timer       vlapic_timer;
     int                timer_pending_count;
-    int                flush_tpr_threshold;
     s_time_t           timer_last_update;
     struct page_info   *regs_page;
     void               *regs;

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