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commit 07bbac08b594741480457c272c5f2d1feee3fbbd
Author: Jan Beulich <jbeulich@suse.com>
AuthorDate: Thu Dec 8 10:11:32 2022 +0100
Commit: Jan Beulich <jbeulich@suse.com>
CommitDate: Thu Dec 8 10:11:32 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@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
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 553c0f76ef..0def33cecf 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 13e2a190b4..235705c8c6 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-4.16