intel_iommu: check and sync host IOMMU cap/ecap in scalable modern mode

When vIOMMU is configured in scalable modern mode, stage-1 page table is
supported. We need to check and sync host side cap/ecap with vIOMMU
cap/ecap.

This happens when PCIe device (i.e., VFIO case) sets IOMMUFDDevice to vIOMMU.
Some of the bits in cap/ecap is user controllable, then user setting is
compared with host cap/ecap for compatibility, i.e., if intel_iommu is
configured in scalable modern but VTD_ECAP_NEST isn't set in host ecap,
that device will fail to attach. For other bits not controlled by user,
i.e. VTD_CAP/ECAP_MASK bits, host cap/ecap is picked.

Below is the sequence to initial and finalize vIOMMU cap/ecap:

vtd_cap_init() initializes iommu->cap/ecap. ---- vtd_cap_init()
iommu->host_cap/ecap is initialized as iommu->cap/ecap.  ---- vtd_init()
iommu->host_cap/ecap is updated some bits(VTD_CAP/ECAP_MASK) with host setting. ---- vtd_sync_hw_info()
iommu->cap/ecap is finalized as iommu->host_cap/ecap.  ---- vtd_machine_done_hook()

iommu->host_cap/ecap is a temporary storage to hold intermediate value
when synthesize host cap/ecap with vIOMMU's initial configured cap/ecap.

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>

hw/i386/intel_iommu.c

@@ -3819,19 +3819,82 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus,
     return vtd_dev_as;
 }
 
+static bool vtd_check_hw_info(IntelIOMMUState *s, struct iommu_hw_info_vtd *vtd,
+                              Error **errp)
+{
+    if (!(vtd->ecap_reg & VTD_ECAP_NEST)) {
+        error_setg(errp, "Need nested translation on host in modern mode");
+        return false;
+    }
+
+    return true;
+}
+
+/* cap/ecap are readonly after vIOMMU finalized */
+static bool vtd_check_hw_info_finalized(IntelIOMMUState *s,
+                                        struct iommu_hw_info_vtd *vtd,
+                                        Error **errp)
+{
+    if (s->cap & ~vtd->cap_reg & VTD_CAP_MASK) {
+        error_setg(errp, "vIOMMU cap %lx isn't compatible with host %llx",
+                   s->cap, vtd->cap_reg);
+        return false;
+    }
+
+    if (s->ecap & ~vtd->ecap_reg & VTD_ECAP_MASK) {
+        error_setg(errp, "vIOMMU ecap %lx isn't compatible with host %llx",
+                   s->ecap, vtd->ecap_reg);
+        return false;
+    }
+
+    if (s->ecap & vtd->ecap_reg & VTD_ECAP_PASID &&
+        VTD_GET_PSS(s->ecap) > VTD_GET_PSS(vtd->ecap_reg)) {
+        error_setg(errp, "vIOMMU pasid bits %lu > host pasid bits %llu",
+                   VTD_GET_PSS(s->ecap), VTD_GET_PSS(vtd->ecap_reg));
+        return false;
+    }
+
+    return true;
+}
+
 static bool vtd_sync_hw_info(IntelIOMMUState *s, struct iommu_hw_info_vtd *vtd,
                              Error **errp)
 {
-    uint64_t addr_width;
+    uint64_t cap, ecap, addr_width, pasid_bits;
 
-    addr_width = (vtd->cap_reg >> 16) & 0x3fULL;
-    if (s->aw_bits > addr_width) {
-        error_setg(errp, "User aw-bits: %u > host address width: %lu",
-                   s->aw_bits, addr_width);
+    if (!s->scalable_modern) {
+        addr_width = (vtd->cap_reg >> 16) & 0x3fULL;
+        if (s->aw_bits > addr_width) {
+            error_setg(errp, "User aw-bits: %u > host address width: %lu",
+                       s->aw_bits, addr_width);
+            return false;
+        }
+        return true;
+    }
+
+    if (!vtd_check_hw_info(s, vtd, errp)) {
         return false;
     }
 
-    /* TODO: check and sync host cap/ecap into vIOMMU cap/ecap */
+    if (s->cap_finalized) {
+        return vtd_check_hw_info_finalized(s, vtd, errp);
+    }
+
+    /* sync host cap/ecap to vIOMMU */
+
+    cap = s->host_cap & vtd->cap_reg & VTD_CAP_MASK;
+    s->host_cap &= ~VTD_CAP_MASK;
+    s->host_cap |= cap;
+    ecap = s->host_ecap & vtd->ecap_reg & VTD_ECAP_MASK;
+    s->host_ecap &= ~VTD_ECAP_MASK;
+    s->host_ecap |= ecap;
+
+    pasid_bits = VTD_GET_PSS(vtd->ecap_reg);
+    if (s->host_ecap & VTD_ECAP_PASID &&
+        VTD_GET_PSS(s->host_ecap) > pasid_bits) {
+        s->host_ecap &= ~VTD_ECAP_PSS_MASK;
+        s->host_ecap |= VTD_ECAP_PSS(pasid_bits);
+    }
 
     return true;
 }
@@ -3873,9 +3936,13 @@ static int vtd_dev_set_iommu_device(PCIBus *bus, void *opaque, int32_t devfn,
 
     assert(0 <= devfn && devfn < PCI_DEVFN_MAX);
 
-    /* None IOMMUFD case */
-    if (!idev) {
+    if (!s->scalable_modern && !idev) {
+        /* Legacy vIOMMU and non-IOMMUFD backend */
         return 0;
+    } else if (!idev) {
+        /* Modern vIOMMU and non-IOMMUFD backend */
+        error_setg(errp, "Need IOMMUFD backend to setup nested page table");
+        return -1;
     }
 
     if (!vtd_check_idev(s, idev, errp)) {

hw/i386/intel_iommu_internal.h

@@ -191,13 +191,19 @@
 #define VTD_ECAP_PT                 (1ULL << 6)
 #define VTD_ECAP_SC                 (1ULL << 7)
 #define VTD_ECAP_MHMV               (15ULL << 20)
+#define VTD_ECAP_NEST               (1ULL << 26)
 #define VTD_ECAP_SRS                (1ULL << 31)
 #define VTD_ECAP_EAFS               (1ULL << 34)
+#define VTD_ECAP_PSS(val)           (((val) & 0x1fULL) << 35)
 #define VTD_ECAP_PASID              (1ULL << 40)
 #define VTD_ECAP_SMTS               (1ULL << 43)
 #define VTD_ECAP_SLTS               (1ULL << 46)
 #define VTD_ECAP_FLTS               (1ULL << 47)
 
+#define VTD_ECAP_MASK               (VTD_ECAP_SRS | VTD_ECAP_EAFS)
+#define VTD_GET_PSS(val)            (((val) >> 35) & 0x1f)
+#define VTD_ECAP_PSS_MASK           (0x1fULL << 35)
+
 /* CAP_REG */
 /* (offset >> 4) << 24 */
 #define VTD_CAP_FRO                 (DMAR_FRCD_REG_OFFSET << 20)
@@ -214,11 +220,15 @@
 #define VTD_CAP_DRAIN_WRITE         (1ULL << 54)
 #define VTD_CAP_DRAIN_READ          (1ULL << 55)
 #define VTD_CAP_FL1GP               (1ULL << 56)
+#define VTD_CAP_FL5LP               (1ULL << 60)
 #define VTD_CAP_DRAIN               (VTD_CAP_DRAIN_READ | VTD_CAP_DRAIN_WRITE)
 #define VTD_CAP_CM                  (1ULL << 7)
 #define VTD_PASID_ID_SHIFT          20
 #define VTD_PASID_ID_MASK           ((1ULL << VTD_PASID_ID_SHIFT) - 1)
 
+
+#define VTD_CAP_MASK                (VTD_CAP_FL1GP | VTD_CAP_FL5LP)
+
 /* Supported Adjusted Guest Address Widths */
 #define VTD_CAP_SAGAW_SHIFT         8
 #define VTD_CAP_SAGAW_MASK          (0x1fULL << VTD_CAP_SAGAW_SHIFT)