[Qemu-devel] [RFC v2 PATCH 1/2] target/arm/kvm: Translate the MSI doorbell in kvm_arch_fixup_msi_route

[Bharat Bhushan <Bharat.Bhushan@nxp.com>]

Translate msi address if device is behind virtio-iommu.
This logic is similar to vSMMUv3/Intel iommu emulation.

This RFC patch does not handle the case where both vsmmuv3 and
virtio-iommu are available.

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
---
v1-v2:
  - Added trace events
  - removed vSMMU3 link in patch description

 target/arm/kvm.c        | 25 +++++++++++++++++++++++++
 target/arm/trace-events |  3 +++
 2 files changed, 28 insertions(+)

diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index 4555468..5a28956 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -21,7 +21,11 @@
 #include "kvm_arm.h"
 #include "cpu.h"
 #include "internals.h"
+#include "trace.h"
 #include "hw/arm/arm.h"
+#include "hw/pci/pci.h"
+#include "hw/pci/msi.h"
+#include "hw/virtio/virtio-iommu.h"
 #include "exec/memattrs.h"
 #include "exec/address-spaces.h"
 #include "hw/boards.h"
@@ -611,6 +615,27 @@ int kvm_arm_vgic_probe(void)
 int kvm_arch_fixup_msi_route(struct kvm_irq_routing_entry *route,
                              uint64_t address, uint32_t data, PCIDevice *dev)
 {
+    AddressSpace *as = pci_device_iommu_address_space(dev);
+    IOMMUTLBEntry entry;
+    IOMMUDevice *sdev;
+    VirtIOIOMMU *s;
+
+    if (as == &address_space_memory) {
+        return 0;
+    }
+
+    /* MSI doorbell address is translated by an IOMMU */
+    sdev = container_of(as, IOMMUDevice, as);
+    s = sdev->viommu;
+
+    entry = s->iommu_ops.translate(&sdev->iommu_mr, address, IOMMU_WO);
+
+    route->u.msi.address_lo = entry.translated_addr;
+    route->u.msi.address_hi = entry.translated_addr >> 32;
+
+    trace_kvm_arm_fixup_msi_route(address, sdev->devfn, sdev->iommu_mr.name,
+                                  entry.translated_addr);
+
     return 0;
 }
 
diff --git a/target/arm/trace-events b/target/arm/trace-events
index e21c84f..eff2822 100644
--- a/target/arm/trace-events
+++ b/target/arm/trace-events
@@ -8,3 +8,6 @@ arm_gt_tval_write(int timer, uint64_t value) "gt_tval_write: timer %d value %" P
 arm_gt_ctl_write(int timer, uint64_t value) "gt_ctl_write: timer %d value %" PRIx64
 arm_gt_imask_toggle(int timer, int irqstate) "gt_ctl_write: timer %d IMASK toggle, new irqstate %d"
 arm_gt_cntvoff_write(uint64_t value) "gt_cntvoff_write: value %" PRIx64
+
+# target/arm/kvm.c
+kvm_arm_fixup_msi_route(uint64_t iova, uint32_t devid, const char *name, uint64_t gpa) "MSI addr = 0x%"PRIx64" is translated for devfn=%d through %s into 0x%"PRIx64
-- 
1.9.3