Correct the highest priority order of irq injection path from userspace

From e6fa298ad00b96fd457c737ec9e100cd3be5f02e Mon Sep 17 00:00:00 2001
From: Dor Laor <dor.laor-atKUWr5tajBWk0Htik3J/[email protected]>
Date: Thu, 13 Dec 2007 15:09:54 +0200
Subject: [PATCH] Correct the highest priority order of irq injection from userspace.
Actually this is not a must here since no more than a single interrupt should be pending so no matter how we scan the vector should be good, so it is more for being correct theoretically.

---
 drivers/kvm/x86.c |   14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)

index c9e4b67..0fac2a1 100644
@@ -2638,7 +2638,7 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu 

*vcpu,
struct kvm_sregs *sregs)

 {
     int mmu_reset_needed = 0;
-    int i, pending_vec, max_bits;
+    int i, pending_vec;
     struct descriptor_table dt;
 
     vcpu_load(vcpu);
@@ -2684,12 +2684,14 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct 
kvm_vcpu *vcpu,
             if (vcpu->irq_pending[i])
                 __set_bit(i, &vcpu->irq_summary);
     } else {

- max_bits = (sizeof sregs->interrupt_bitmap) << 3;
- pending_vec = find_first_bit(
- (const unsigned long *)sregs->interrupt_bitmap,
- max_bits);
+ for (i = sizeof sregs->interrupt_bitmap/sizeof(long) - 1;i;i--) {
+ pending_vec = __fls(((unsigned long
*)sregs->interrupt_bitmap)[i]);
+ if (pending_vec) break;
+ }
+

         /* Only pending external irq is handled here */
-        if (pending_vec < max_bits) {
+        if (pending_vec) {
+            pending_vec += i * BITS_PER_LONG;
             kvm_x86_ops->set_irq(vcpu, pending_vec);
             pr_debug("Set back pending irq %d\n",
                  pending_vec);

1.5.3.3


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