intel_iommu: add support for split irqchip

In split irqchip mode, IOAPIC is working in user space, only update
kernel irq routes when entry changed. When IR is enabled, we directly
update the kernel with translated messages. It works just like a kernel
cache for the remapping entries.

Since KVM irqfd is using kernel gsi routes to deliver interrupts, as
long as we can support split irqchip, we will support irqfd as
well. Also, since kernel gsi routes will cache translated interrupts,
irqfd delivery will not suffer from any performance impact due to IR.

And, since we supported irqfd, vhost devices will be able to work
seamlessly with IR now. Logically this should contain both vhost-net and
vhost-user case.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[move trace-events lines into target-i386/trace-events]
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

6 files changed, 45 insertions, 0 deletions

diff --git a/Makefile.objs b/Makefile.objs
index 7f1f0a3ffd..6d5ddcfd3e 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -153,6 +153,7 @@ trace-events-y += hw/alpha/trace-events
 trace-events-y += ui/trace-events
 trace-events-y += audio/trace-events
 trace-events-y += net/trace-events
+trace-events-y += target-i386/trace-events
 trace-events-y += target-sparc/trace-events
 trace-events-y += target-s390x/trace-events
 trace-events-y += target-ppc/trace-events
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 6ba5520283..c7ded0fc81 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -2165,6 +2165,12 @@ do_not_translate:
     return 0;
 }
 
+static int vtd_int_remap(X86IOMMUState *iommu, MSIMessage *src,
+                         MSIMessage *dst, uint16_t sid)
+{
+    return vtd_interrupt_remap_msi(INTEL_IOMMU_DEVICE(iommu), src, dst);
+}
+
 static MemTxResult vtd_mem_ir_read(void *opaque, hwaddr addr,
                                    uint64_t *data, unsigned size,
                                    MemTxAttrs attrs)
@@ -2399,6 +2405,7 @@ static void vtd_class_init(ObjectClass *klass, void *data)
     dc->props = vtd_properties;
     dc->hotpluggable = false;
     x86_class->realize = vtd_realize;
+    x86_class->int_remap = vtd_int_remap;
 }
 
 static const TypeInfo vtd_info = {
diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index cdbbddd79e..e048ced5d5 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -26,6 +26,7 @@
 #include "hw/i386/x86-iommu.h"
 #include "hw/i386/ioapic.h"
 #include "hw/pci/msi.h"
+#include "hw/sysbus.h"
 
 #define TYPE_INTEL_IOMMU_DEVICE "intel-iommu"
 #define INTEL_IOMMU_DEVICE(obj) \
diff --git a/include/hw/i386/x86-iommu.h b/include/hw/i386/x86-iommu.h
index 699dd0615c..fa6ce31b74 100644
--- a/include/hw/i386/x86-iommu.h
+++ b/include/hw/i386/x86-iommu.h
@@ -21,6 +21,7 @@
 #define IOMMU_COMMON_H
 
 #include "hw/sysbus.h"
+#include "hw/pci/pci.h"
 
 #define  TYPE_X86_IOMMU_DEVICE  ("x86-iommu")
 #define  X86_IOMMU_DEVICE(obj) \
@@ -31,6 +32,7 @@
     OBJECT_GET_CLASS(X86IOMMUClass, obj, TYPE_X86_IOMMU_DEVICE)
 
 #define X86_IOMMU_PCI_DEVFN_MAX           256
+#define X86_IOMMU_SID_INVALID             (0xffff)
 
 typedef struct X86IOMMUState X86IOMMUState;
 typedef struct X86IOMMUClass X86IOMMUClass;
@@ -39,6 +41,9 @@ struct X86IOMMUClass {
     SysBusDeviceClass parent;
     /* Intel/AMD specific realize() hook */
     DeviceRealize realize;
+    /* MSI-based interrupt remapping */
+    int (*int_remap)(X86IOMMUState *iommu, MSIMessage *src,
+                     MSIMessage *dst, uint16_t sid);
 };
 
 struct X86IOMMUState {
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 93275231ec..9c00e48952 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -35,6 +35,7 @@
 #include "hw/i386/apic.h"
 #include "hw/i386/apic_internal.h"
 #include "hw/i386/apic-msidef.h"
+#include "hw/i386/intel_iommu.h"
 
 #include "exec/ioport.h"
 #include "standard-headers/asm-x86/hyperv.h"
@@ -42,6 +43,7 @@
 #include "hw/pci/msi.h"
 #include "migration/migration.h"
 #include "exec/memattrs.h"
+#include "trace.h"
 
 //#define DEBUG_KVM
 
@@ -3371,6 +3373,31 @@ int kvm_device_msix_deassign(KVMState *s, uint32_t dev_id)
 int kvm_arch_fixup_msi_route(struct kvm_irq_routing_entry *route,
                              uint64_t address, uint32_t data, PCIDevice *dev)
 {
+    X86IOMMUState *iommu = x86_iommu_get_default();
+
+    if (iommu) {
+        int ret;
+        MSIMessage src, dst;
+        X86IOMMUClass *class = X86_IOMMU_GET_CLASS(iommu);
+
+        src.address = route->u.msi.address_hi;
+        src.address <<= VTD_MSI_ADDR_HI_SHIFT;
+        src.address |= route->u.msi.address_lo;
+        src.data = route->u.msi.data;
+
+        ret = class->int_remap(iommu, &src, &dst, dev ? \
+                               pci_requester_id(dev) : \
+                               X86_IOMMU_SID_INVALID);
+        if (ret) {
+            trace_kvm_x86_fixup_msi_error(route->gsi);
+            return 1;
+        }
+
+        route->u.msi.address_hi = dst.address >> VTD_MSI_ADDR_HI_SHIFT;
+        route->u.msi.address_lo = dst.address & VTD_MSI_ADDR_LO_MASK;
+        route->u.msi.data = dst.data;
+    }
+
     return 0;
 }
 
diff --git a/target-i386/trace-events b/target-i386/trace-events
new file mode 100644
index 0000000000..2113075cd1
--- /dev/null
+++ b/target-i386/trace-events
@@ -0,0 +1,4 @@
+# See docs/trace-events.txt for syntax documentation.
+
+# target-i386/kvm.c
+kvm_x86_fixup_msi_error(uint32_t gsi) "VT-d failed to remap interrupt for GSI %" PRIu32