Re: [Patch v5] x86: irq_comm: Add check for RH bit in kvm_set_msi_irq

["Radim Krčmář" <rkrcmar@redhat.com>]

2015-03-23 16:46-0600, James Sullivan:
> On 03/23/2015 03:13 PM, Radim Krčmář wrote:
> > I meant if the delivery mode from data register isn't ignored with RH=1,
> > and the message delivered as if lowest-priority was set there.
> > (Decided by having something else than fixed or lowest-priority there.)
> > 
> 
> Hmm, any thoughts on how I could test for that?

Set the MSI data register's delivery mode to NMI/SMI/...
The change below fails => hardware honors delivery mode.

I tested it and Linux got a lot of unexpected NMIs, so the emulation in
your latest patch looks correct.

diff --git a/arch/x86/include/asm/msidef.h b/arch/x86/include/asm/msidef.h
index 4cc48af23fef..2270e459186b 100644
--- a/arch/x86/include/asm/msidef.h
+++ b/arch/x86/include/asm/msidef.h
@@ -17,6 +17,7 @@
 #define MSI_DATA_DELIVERY_MODE_SHIFT	8
 #define  MSI_DATA_DELIVERY_FIXED	(0 << MSI_DATA_DELIVERY_MODE_SHIFT)
 #define  MSI_DATA_DELIVERY_LOWPRI	(1 << MSI_DATA_DELIVERY_MODE_SHIFT)
+#define  MSI_DATA_DELIVERY_NMI		(4 << MSI_DATA_DELIVERY_MODE_SHIFT)
 
 #define MSI_DATA_LEVEL_SHIFT		14
 #define	 MSI_DATA_LEVEL_DEASSERT	(0 << MSI_DATA_LEVEL_SHIFT)
diff --git a/arch/x86/kernel/apic/msi.c b/arch/x86/kernel/apic/msi.c
index d6ba2d660dc5..4f71737c34eb 100644
--- a/arch/x86/kernel/apic/msi.c
+++ b/arch/x86/kernel/apic/msi.c
@@ -46,7 +46,7 @@ void native_compose_msi_msg(struct pci_dev *pdev,
 		MSI_DATA_LEVEL_ASSERT |
 		((apic->irq_delivery_mode != dest_LowestPrio) ?
 			MSI_DATA_DELIVERY_FIXED :
-			MSI_DATA_DELIVERY_LOWPRI) |
+			MSI_DATA_DELIVERY_NMI) |
 		MSI_DATA_VECTOR(cfg->vector);
 }