[Xen-devel] [PATCH] Adding back guest MSI eoi support for unmaskable MSI interrupt

[Haitao Shan <maillists.shan@xxxxxxxxx>]

Hi, Keir,

Sorry, I made a mistake when removing the MSI IRQ storm logic by
wrongly removing the guest MSI EOI hook for unmaskable MSI interrupt.
Unmaskable MSI interrupt is of ACKTYPE_EOI and hook on guest MSI EOI
writes are needed. And IRQ ratelimit has no effect on this type of
interrupt (since the "disable" IRQ logic actually did nothing for
unmaskable MSI). So I add them back with this patch.
Could you please review what I missed in the attached patch? Thanks in advance!

Note: guest MSI EOI hook for ACKTYPE_NONE IRQ is *not* adding back.
The MSI IRQ storm (originally for maskable MSI) logic still keeps
removed.

Description:

This patch adds back proper guest MSI EOI hook for correctly handling
unmaskable MSI interrupt, which is wrongly removed by changset 23703.

Signed-off-by:           Shan Haitao <haitao.shan@xxxxxxxxx>

diff -r 31dd84463eec xen/arch/x86/hvm/vlapic.c
--- a/xen/arch/x86/hvm/vlapic.c Sat Jul 16 09:25:48 2011 +0100
+++ b/xen/arch/x86/hvm/vlapic.c Mon Jul 18 14:13:19 2011 +0800
@@ -400,6 +400,8 @@ void vlapic_EOI_set(struct vlapic *vlapi

     if ( vlapic_test_and_clear_vector(vector, &vlapic->regs->data[APIC_TMR]) )
         vioapic_update_EOI(vlapic_domain(vlapic), vector);
+
+    hvm_dpci_msi_eoi(current->domain, vector);
 }

 int vlapic_ipi(
diff -r 31dd84463eec xen/drivers/passthrough/io.c
--- a/xen/drivers/passthrough/io.c      Sat Jul 16 09:25:48 2011 +0100
+++ b/xen/drivers/passthrough/io.c      Mon Jul 18 14:13:19 2011 +0800
@@ -421,6 +421,56 @@ int hvm_do_IRQ_dpci(struct domain *d, st
 }

 #ifdef SUPPORT_MSI_REMAPPING
+/* called with d->event_lock held */
+static void __msi_pirq_eoi(struct hvm_pirq_dpci *pirq_dpci)
+{
+    irq_desc_t *desc;
+
+    if ( (pirq_dpci->flags & HVM_IRQ_DPCI_MAPPED) &&
+         (pirq_dpci->flags & HVM_IRQ_DPCI_MACH_MSI) )
+    {
+        struct pirq *pirq = dpci_pirq(pirq_dpci);
+
+        BUG_ON(!local_irq_is_enabled());
+        desc = pirq_spin_lock_irq_desc(pirq, NULL);
+        if ( !desc )
+            return;
+        desc_guest_eoi(desc, pirq);
+    }
+}
+
+static int _hvm_dpci_msi_eoi(struct domain *d,
+                             struct hvm_pirq_dpci *pirq_dpci, void *arg)
+{
+    int vector = (long)arg;
+
+    if ( (pirq_dpci->flags & HVM_IRQ_DPCI_MACH_MSI) &&
+         (pirq_dpci->gmsi.gvec == vector) )
+    {
+        int dest = pirq_dpci->gmsi.gflags & VMSI_DEST_ID_MASK;
+        int dest_mode = !!(pirq_dpci->gmsi.gflags & VMSI_DM_MASK);
+
+        if ( vlapic_match_dest(vcpu_vlapic(current), NULL, 0, dest,
+                               dest_mode) )
+        {
+            __msi_pirq_eoi(pirq_dpci);
+            return 1;
+        }
+    }
+
+    return 0;
+}
+
+void hvm_dpci_msi_eoi(struct domain *d, int vector)
+{
+    if ( !iommu_enabled || !d->arch.hvm_domain.irq.dpci )
+       return;
+
+    spin_lock(&d->event_lock);
+    pt_pirq_iterate(d, _hvm_dpci_msi_eoi, (void *)(long)vector);
+    spin_unlock(&d->event_lock);
+}
+
 static int hvm_pci_msi_assert(struct domain *d,
                               struct hvm_pirq_dpci *pirq_dpci)
 {
@@ -458,6 +508,14 @@ static int _hvm_dirq_assist(struct domai
             else
                 hvm_pci_intx_assert(d, device, intx);
             pirq_dpci->pending++;
+
+#ifdef SUPPORT_MSI_REMAPPING
+            if ( pirq_dpci->flags & HVM_IRQ_DPCI_TRANSLATE )
+            {
+                /* for translated MSI to INTx interrupt, eoi as early
as possible */
+                __msi_pirq_eoi(pirq_dpci);
+            }
+#endif
         }

         /*
diff -r 31dd84463eec xen/include/asm-x86/hvm/io.h
--- a/xen/include/asm-x86/hvm/io.h      Sat Jul 16 09:25:48 2011 +0100
+++ b/xen/include/asm-x86/hvm/io.h      Mon Jul 18 14:13:19 2011 +0800
@@ -139,5 +139,6 @@ struct hvm_hw_stdvga {
 void stdvga_init(struct domain *d);
 void stdvga_deinit(struct domain *d);

+extern void hvm_dpci_msi_eoi(struct domain *d, int vector);
 #endif /* __ASM_X86_HVM_IO_H__ */

Attachment: add_msi_eoi_logic_for_unmaskable_msi.patch
Description: Binary data

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel