[PATCH v6 19/19] intel_iommu: Check compatibility with host IOMMU capabilities

[Zhenzhong Duan]

If check fails, host device (either VFIO or VDPA device) is not
compatible with current vIOMMU config and should not be passed to
guest.

Only aw_bits is checked for now, we don't care other capabilities
before scalable modern mode is introduced.

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
 hw/i386/intel_iommu.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 747c988bc4..d8202a77dd 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -3819,6 +3819,30 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, 
PCIBus *bus,
     return vtd_dev_as;
 }
 
+static bool vtd_check_hdev(IntelIOMMUState *s, HostIOMMUDevice *hiod,
+                           Error **errp)
+{
+    HostIOMMUDeviceClass *hiodc = HOST_IOMMU_DEVICE_GET_CLASS(hiod);
+    int ret;
+
+    if (!hiodc->get_cap) {
+        error_setg(errp, ".get_cap() not implemented");
+        return false;
+    }
+
+    /* Common checks */
+    ret = hiodc->get_cap(hiod, HOST_IOMMU_DEVICE_CAP_AW_BITS, errp);
+    if (ret < 0) {
+        return false;
+    }
+    if (s->aw_bits > ret) {
+        error_setg(errp, "aw-bits %d > host aw-bits %d", s->aw_bits, ret);
+        return false;
+    }
+
+    return true;
+}
+
 static bool vtd_dev_set_iommu_device(PCIBus *bus, void *opaque, int devfn,
                                      HostIOMMUDevice *hiod, Error **errp)
 {
@@ -3842,6 +3866,11 @@ static bool vtd_dev_set_iommu_device(PCIBus *bus, void 
*opaque, int devfn,
         return false;
     }
 
+    if (!vtd_check_hdev(s, hiod, errp)) {
+        vtd_iommu_unlock(s);
+        return false;
+    }
+
     vtd_hdev = g_malloc0(sizeof(VTDHostIOMMUDevice));
     vtd_hdev->bus = bus;
     vtd_hdev->devfn = (uint8_t)devfn;
-- 
2.34.1