[xen stable-4.17] x86/HVM: don't mark external IRQs as pending when vLAPIC is disabled

[patchbot@xxxxxxx]

commit 54bb56e12868100c5ce06e33b4f57b6b2b8f37b9
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Dec 20 13:44:07 2022 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Dec 20 13:44:07 2022 +0100

    x86/HVM: don't mark external IRQs as pending when vLAPIC is disabled
    
    In software-disabled state an LAPIC does not accept any interrupt
    requests and hence no IRR bit would newly become set while in this
    state. As a result it is also wrong for us to mark IO-APIC or MSI
    originating vectors as having a pending request when the vLAPIC is in
    this state. Such interrupts are simply lost.
    
    Introduce (IO-APIC) or re-use (MSI) a local variable to help
    readability.
    
    Fixes: 4fe21ad3712e ("This patch add virtual IOAPIC support for VMX guest")
    Fixes: 85715f4bc7c9 ("MSI 5/6: add MSI support to passthrough HVM domain")
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    master commit: f1d7aac1e3c3cd164e17d41791a575a5c3e87121
    master date: 2022-12-02 10:35:01 +0100
---
 xen/arch/x86/hvm/vioapic.c |  9 +++++++--
 xen/arch/x86/hvm/vmsi.c    | 10 ++++++----
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/hvm/vioapic.c b/xen/arch/x86/hvm/vioapic.c
index cb7f440160..41e3c4d5e4 100644
--- a/xen/arch/x86/hvm/vioapic.c
+++ b/xen/arch/x86/hvm/vioapic.c
@@ -460,9 +460,14 @@ static void vioapic_deliver(struct hvm_vioapic *vioapic, 
unsigned int pin)
 
     case dest_Fixed:
         for_each_vcpu ( d, v )
-            if ( vlapic_match_dest(vcpu_vlapic(v), NULL, 0, dest, dest_mode) )
-                ioapic_inj_irq(vioapic, vcpu_vlapic(v), vector, trig_mode,
+        {
+            struct vlapic *vlapic = vcpu_vlapic(v);
+
+            if ( vlapic_enabled(vlapic) &&
+                 vlapic_match_dest(vlapic, NULL, 0, dest, dest_mode) )
+                ioapic_inj_irq(vioapic, vlapic, vector, trig_mode,
                                delivery_mode);
+        }
         break;
 
     case dest_NMI:
diff --git a/xen/arch/x86/hvm/vmsi.c b/xen/arch/x86/hvm/vmsi.c
index 75f92885dc..3cd4923060 100644
--- a/xen/arch/x86/hvm/vmsi.c
+++ b/xen/arch/x86/hvm/vmsi.c
@@ -87,10 +87,12 @@ int vmsi_deliver(
 
     case dest_Fixed:
         for_each_vcpu ( d, v )
-            if ( vlapic_match_dest(vcpu_vlapic(v), NULL,
-                                   0, dest, dest_mode) )
-                vmsi_inj_irq(vcpu_vlapic(v), vector,
-                             trig_mode, delivery_mode);
+        {
+            target = vcpu_vlapic(v);
+            if ( vlapic_enabled(target) &&
+                 vlapic_match_dest(target, NULL, 0, dest, dest_mode) )
+                vmsi_inj_irq(target, vector, trig_mode, delivery_mode);
+        }
         break;
 
     default:
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.17