From: Don Dutile <ddutile@redhat.com>
Date: Fri, 11 Jan 2008 16:22:47 -0500
Subject: [xen] move hvm_maybe_deassert_evtchn_irq early
Message-id: 4787DE27.8000107@redhat.com
O-Subject: [RHEL5.2 PATCH] [Xen][4/4]: High Intr and Softintr rate in HVM's with pv-on-hvm drivers
Bugzilla: 412721

Patch 4/4: hvm-maybe-deassert-evtchn-irq-early.patch

The final patch for the emulated IOAPIC patch for 3.1.2.
Without this patch, HVMs running pv-on-hvm drivers see
twice as many interrupts and soft intr's as one without
this patch.

It ensures that the virtual intr is cleared early-on,
avoiding duplicate servicing of virtual interrupts.

This is from upstream xen-3.1-testing, cset 15591
	http://xenbits.xensource.com/staging/xen-3.1-testing.hg?rev/5a64f1bf9460

Please review & ACK.

- Don

# HG changeset patch
# User Keir Fraser <keir.fraser@citrix.com>
# Date 1200049582 0
# Node ID 5a64f1bf9460c601bd3aa8089a3419535ec740ba
# Parent f479c2af0825f79b5082779c7f09c4cdd204993c
x86 hvm: hvm_maybe_deassert_evtchn_irq() needs to be called early in
vmexit handling, before IO-APIC can be EOIed or unmasked and resample
the fake INTx line.
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
xen-unstable changeset:   16705:e4fd457a3dd5eebf059b49340bb7f3aea1239d8f
xen-unstable date:        Fri Jan 11 10:53:44 2008 +0000

Acked-by: Herbert Xu <herbert.xu@redhat.com>
Acked-by: Bill Burns <bburns@redhat.com>
Acked-by: "Stephen C. Tweedie" <sct@redhat.com>

diff --git a/arch/x86/hvm/svm/intr.c b/arch/x86/hvm/svm/intr.c
index 757d34f..2215d86 100644
--- a/arch/x86/hvm/svm/intr.c
+++ b/arch/x86/hvm/svm/intr.c
@@ -124,7 +124,7 @@ asmlinkage void svm_intr_assist(void)
 
     /* Crank the handle on interrupt state and check for new interrrupts. */
     pt_update_irq(v);
-    hvm_maybe_deassert_evtchn_irq();
+
     do {
         if ( !cpu_has_pending_irq(v) )
             goto out;
diff --git a/arch/x86/hvm/svm/svm.c b/arch/x86/hvm/svm/svm.c
index 23a44cd..31359a3 100644
--- a/arch/x86/hvm/svm/svm.c
+++ b/arch/x86/hvm/svm/svm.c
@@ -2408,6 +2408,8 @@ asmlinkage void svm_vmexit_handler(struct cpu_user_regs *regs)
     perfc_incra(svmexits, exit_reason);
     eip = vmcb->rip;
 
+    hvm_maybe_deassert_evtchn_irq();
+
     switch ( exit_reason )
     {
     case VMEXIT_INTR:
diff --git a/arch/x86/hvm/vmx/intr.c b/arch/x86/hvm/vmx/intr.c
index a1aa73e..2ebb4cd 100644
--- a/arch/x86/hvm/vmx/intr.c
+++ b/arch/x86/hvm/vmx/intr.c
@@ -115,8 +115,6 @@ asmlinkage void vmx_intr_assist(void)
 
     pt_update_irq(v);
 
-    hvm_maybe_deassert_evtchn_irq();
-
     update_tpr_threshold(vcpu_vlapic(v));
 
     do {
diff --git a/arch/x86/hvm/vmx/vmx.c b/arch/x86/hvm/vmx/vmx.c
index 575ad23..777a7b3 100644
--- a/arch/x86/hvm/vmx/vmx.c
+++ b/arch/x86/hvm/vmx/vmx.c
@@ -2936,6 +2936,8 @@ asmlinkage void vmx_vmexit_handler(struct cpu_user_regs *regs)
     if ( unlikely(exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY) )
         return vmx_failed_vmentry(exit_reason, regs);
 
+    hvm_maybe_deassert_evtchn_irq();
+
     switch ( exit_reason )
     {
     case EXIT_REASON_EXCEPTION_NMI: