[Xen-devel] [PATCH] xen: implement vector callback for evtchn delivery

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

Hi all,
this patch implements the vector callback mechanism in Xen and it is based
on Sheng's work so he should be considered the original author.

I realize now that the tsc_mode patch I sent before only applies on top
of this one.

Signed-off-by: Sheng Yang <sheng@xxxxxxxxxxxxxxx>
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

---

diff --git a/xen/arch/x86/hvm/irq.c b/xen/arch/x86/hvm/irq.c
--- a/xen/arch/x86/hvm/irq.c
+++ b/xen/arch/x86/hvm/irq.c
@@ -185,16 +185,16 @@
 
 void hvm_assert_evtchn_irq(struct vcpu *v)
 {
-    if ( v->vcpu_id != 0 )
-        return;
-
     if ( unlikely(in_irq() || !local_irq_is_enabled()) )
     {
         tasklet_schedule(&v->arch.hvm_vcpu.assert_evtchn_irq_tasklet);
         return;
     }
 
-    hvm_set_callback_irq_level(v);
+    if (is_hvm_pv_evtchn_vcpu(v))
+        vcpu_kick(v);
+    else
+        hvm_set_callback_irq_level(v);
 }
 
 void hvm_set_pci_link_route(struct domain *d, u8 link, u8 isa_irq)
@@ -251,7 +251,7 @@
 
     via_type = (uint8_t)(via >> 56) + 1;
     if ( ((via_type == HVMIRQ_callback_gsi) && (via == 0)) ||
-         (via_type > HVMIRQ_callback_pci_intx) )
+         (via_type > HVMIRQ_callback_vector) )
         via_type = HVMIRQ_callback_none;
 
     spin_lock(&d->arch.hvm_domain.irq_lock);
@@ -297,6 +297,9 @@
         if ( hvm_irq->callback_via_asserted )
              __hvm_pci_intx_assert(d, pdev, pintx);
         break;
+    case HVMIRQ_callback_vector:
+        hvm_irq->callback_via.vector = (uint8_t)via;
+        break;
     default:
         break;
     }
@@ -312,6 +315,10 @@
     case HVMIRQ_callback_pci_intx:
         printk("PCI INTx Dev 0x%02x Int%c\n", pdev, 'A' + pintx);
         break;
+    case HVMIRQ_callback_vector:
+        printk("Set HVMIRQ_callback_vector to %u\n",
+               hvm_irq->callback_via.vector);
+        break;
     default:
         printk("None\n");
         break;
@@ -323,6 +330,10 @@
     struct hvm_domain *plat = &v->domain->arch.hvm_domain;
     int vector;
 
+    if (plat->irq.callback_via_type == HVMIRQ_callback_vector &&
+            vcpu_info(v, evtchn_upcall_pending))
+        return hvm_intack_vector(plat->irq.callback_via.vector);
+ 
     if ( unlikely(v->nmi_pending) )
         return hvm_intack_nmi;
 
@@ -363,6 +374,8 @@
     case hvm_intsrc_lapic:
         if ( !vlapic_ack_pending_irq(v, intack.vector) )
             intack = hvm_intack_none;
+        break;
+    case hvm_intsrc_vector:
         break;
     default:
         intack = hvm_intack_none;
diff --git a/xen/arch/x86/hvm/vmx/intr.c b/xen/arch/x86/hvm/vmx/intr.c
--- a/xen/arch/x86/hvm/vmx/intr.c
+++ b/xen/arch/x86/hvm/vmx/intr.c
@@ -164,7 +164,8 @@
     {
         HVMTRACE_2D(INJ_VIRQ, intack.vector, /*fake=*/ 0);
         vmx_inject_extint(intack.vector);
-        pt_intr_post(v, intack);
+        if (intack.source != hvm_intsrc_vector)
+             pt_intr_post(v, intack);
     }
 
     /* Is there another IRQ to queue up behind this one? */
diff --git a/xen/common/kernel.c b/xen/common/kernel.c
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -243,6 +243,8 @@
                 fi.submap |= (1U << XENFEAT_mmu_pt_update_preserve_ad) |
                              (1U << XENFEAT_highmem_assist) |
                              (1U << XENFEAT_gnttab_map_avail_bits);
+            else
+                fi.submap |= (1U << XENFEAT_hvm_callback_vector);
 #endif
             break;
         default:
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -33,7 +33,8 @@
     hvm_intsrc_pic,
     hvm_intsrc_lapic,
     hvm_intsrc_nmi,
-    hvm_intsrc_mce
+    hvm_intsrc_mce,
+    hvm_intsrc_vector
 };
 struct hvm_intack {
     uint8_t source; /* enum hvm_intsrc */
@@ -44,6 +45,7 @@
 #define hvm_intack_lapic(vec) ( (struct hvm_intack) { hvm_intsrc_lapic, vec } )
 #define hvm_intack_nmi        ( (struct hvm_intack) { hvm_intsrc_nmi,   2 } )
 #define hvm_intack_mce        ( (struct hvm_intack) { hvm_intsrc_mce,   18 } )
+#define hvm_intack_vector(vec)( (struct hvm_intack) { hvm_intsrc_vector, vec } 
)
 enum hvm_intblk {
     hvm_intblk_none,      /* not blocked (deliverable) */
     hvm_intblk_shadow,    /* MOV-SS or STI shadow */
diff --git a/xen/include/asm-x86/hvm/irq.h b/xen/include/asm-x86/hvm/irq.h
--- a/xen/include/asm-x86/hvm/irq.h
+++ b/xen/include/asm-x86/hvm/irq.h
@@ -54,12 +54,14 @@
         enum {
             HVMIRQ_callback_none,
             HVMIRQ_callback_gsi,
-            HVMIRQ_callback_pci_intx
+            HVMIRQ_callback_pci_intx,
+            HVMIRQ_callback_vector
         } callback_via_type;
     };
     union {
         uint32_t gsi;
         struct { uint8_t dev, intx; } pci;
+        uint32_t vector;
     } callback_via;
 
     /* Number of INTx wires asserting each PCI-ISA link. */
diff --git a/xen/include/public/features.h b/xen/include/public/features.h
--- a/xen/include/public/features.h
+++ b/xen/include/public/features.h
@@ -68,6 +68,9 @@
  */
 #define XENFEAT_gnttab_map_avail_bits      7
 
+/* x86: Does this Xen host support the HVM callback vector type? */
+#define XENFEAT_hvm_callback_vector        8
+
 #define XENFEAT_NR_SUBMAPS 1
 
 #endif /* __XEN_PUBLIC_FEATURES_H__ */
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -592,6 +592,9 @@
 #define VM_ASSIST(_d,_t) (test_bit((_t), &(_d)->vm_assist))
 
 #define is_hvm_domain(d) ((d)->is_hvm)
+#define is_hvm_pv_evtchn_domain(d) (is_hvm_domain(d) && \
+           d->arch.hvm_domain.irq.callback_via_type == HVMIRQ_callback_vector)
+#define is_hvm_pv_evtchn_vcpu(v) (is_hvm_pv_evtchn_domain(v->domain))
 #define is_hvm_vcpu(v)   (is_hvm_domain(v->domain))
 #define need_iommu(d)    ((d)->need_iommu)
 

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