[PATCH 1/7] VT-d: parse ACPI "SoC Integrated Address Translation Cache Reporting Structure"s

[Jan Beulich <jbeulich@xxxxxxxx>]

This is a prereq to us, in particular, respecting the "ATC required"
flag.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
Should we check scope entries for appropriate types? (If so, then also
for e.g. ATSR.)

--- a/xen/drivers/passthrough/vtd/dmar.c
+++ b/xen/drivers/passthrough/vtd/dmar.c
@@ -47,6 +47,7 @@ LIST_HEAD_READ_MOSTLY(acpi_drhd_units);
 LIST_HEAD_READ_MOSTLY(acpi_rmrr_units);
 static LIST_HEAD_READ_MOSTLY(acpi_atsr_units);
 static LIST_HEAD_READ_MOSTLY(acpi_rhsa_units);
+static LIST_HEAD_READ_MOSTLY(acpi_satc_units);
 
 static struct acpi_table_header *__read_mostly dmar_table;
 static int __read_mostly dmar_flags;
@@ -764,6 +765,95 @@ acpi_parse_one_rhsa(struct acpi_dmar_hea
     return ret;
 }
 
+static int __init register_one_satc(struct acpi_satc_unit *satcu)
+{
+    bool ignore = false;
+    unsigned int i = 0;
+    int ret = 0;
+
+    /* Skip checking if segment is not accessible yet. */
+    if ( !pci_known_segment(satcu->segment) )
+        i = UINT_MAX;
+
+    for ( ; i < satcu->scope.devices_cnt; i++ )
+    {
+        uint8_t b = PCI_BUS(satcu->scope.devices[i]);
+        uint8_t d = PCI_SLOT(satcu->scope.devices[i]);
+        uint8_t f = PCI_FUNC(satcu->scope.devices[i]);
+
+        if ( pci_device_detect(satcu->segment, b, d, f) == 0 )
+        {
+            dprintk(XENLOG_WARNING VTDPREFIX,
+                    " Non-existent device (%pp) is reported in SATC scope!\n",
+                    &PCI_SBDF(satcu->segment, b, d, f));
+            ignore = true;
+        }
+        else
+        {
+            ignore = false;
+            break;
+        }
+    }
+
+    if ( ignore )
+    {
+        dprintk(XENLOG_WARNING VTDPREFIX,
+                " Ignore SATC for seg %04x as no device under its scope is PCI 
discoverable!\n",
+                satcu->segment);
+        scope_devices_free(&satcu->scope);
+        xfree(satcu);
+        return 1;
+    }
+
+    if ( iommu_verbose )
+        printk(VTDPREFIX " ATC required: %d\n", satcu->atc_required);
+
+    list_add(&satcu->list, &acpi_satc_units);
+
+    return ret;
+}
+
+static int __init
+acpi_parse_one_satc(const struct acpi_dmar_header *header)
+{
+    const struct acpi_dmar_satc *satc =
+        container_of(header, const struct acpi_dmar_satc, header);
+    struct acpi_satc_unit *satcu;
+    const void *dev_scope_start, *dev_scope_end;
+    int ret;
+
+    if ( (ret = acpi_dmar_check_length(header, sizeof(*satc))) != 0 )
+        return ret;
+
+    satcu = xzalloc(struct acpi_satc_unit);
+    if ( !satcu )
+        return -ENOMEM;
+
+    satcu->segment = satc->segment;
+    satcu->atc_required = satc->flags & 1;
+
+    dev_scope_start = (const void *)(satc + 1);
+    dev_scope_end   = (const void *)satc + header->length;
+    ret = acpi_parse_dev_scope(dev_scope_start, dev_scope_end,
+                               &satcu->scope, SATC_TYPE, satc->segment);
+
+    if ( !ret && satcu->scope.devices_cnt )
+    {
+        ret = register_one_satc(satcu);
+        /*
+         * register_one_satc() returns greater than 0 when a specified
+         * PCIe device cannot be detected. To prevent VT-d from being
+         * disabled in such cases, reset the return value to 0 here.
+         */
+        if ( ret > 0 )
+            ret = 0;
+    }
+    else
+        xfree(satcu);
+
+    return ret;
+}
+
 static int __init cf_check acpi_parse_dmar(struct acpi_table_header *table)
 {
     struct acpi_table_dmar *dmar;
@@ -817,6 +907,11 @@ static int __init cf_check acpi_parse_dm
                 printk(VTDPREFIX "found ACPI_DMAR_RHSA:\n");
             ret = acpi_parse_one_rhsa(entry_header);
             break;
+        case ACPI_DMAR_TYPE_SATC:
+            if ( iommu_verbose )
+                printk(VTDPREFIX "found ACPI_DMAR_SATC:\n");
+            ret = acpi_parse_one_satc(entry_header);
+            break;
         default:
             dprintk(XENLOG_WARNING VTDPREFIX,
                     "Ignore unknown DMAR structure type (%#x)\n",
--- a/xen/drivers/passthrough/vtd/dmar.h
+++ b/xen/drivers/passthrough/vtd/dmar.h
@@ -91,6 +91,13 @@ struct acpi_rhsa_unit {
     u32    proximity_domain;
 };
 
+struct acpi_satc_unit {
+    struct dmar_scope scope;
+    struct list_head list;
+    uint16_t segment;
+    bool atc_required:1;
+};
+
 #define for_each_drhd_unit(drhd) \
     list_for_each_entry(drhd, &acpi_drhd_units, list)
 
@@ -106,6 +113,7 @@ struct acpi_atsr_unit *acpi_find_matched
 #define DMAR_TYPE 1
 #define RMRR_TYPE 2
 #define ATSR_TYPE 3
+#define SATC_TYPE 4
 
 #define DMAR_OPERATION_TIMEOUT MILLISECS(1000)
 
--- a/xen/include/acpi/actbl2.h
+++ b/xen/include/acpi/actbl2.h
@@ -345,7 +345,8 @@ enum acpi_dmar_type {
        ACPI_DMAR_TYPE_RESERVED_MEMORY = 1,
        ACPI_DMAR_TYPE_ATSR = 2,
        ACPI_DMAR_HARDWARE_AFFINITY = 3,
-       ACPI_DMAR_TYPE_RESERVED = 4     /* 4 and greater are reserved */
+       ACPI_DMAR_TYPE_SATC = 5,
+       ACPI_DMAR_TYPE_RESERVED = 7     /* 7 and greater are reserved */
 };
 
 /* DMAR Device Scope structure */
@@ -427,6 +428,15 @@ struct acpi_dmar_rhsa {
        u32 proximity_domain;
 };
 
+/* 5: SOC Integrated Address Translation Cache Reporting Structure */
+
+struct acpi_dmar_satc {
+       struct acpi_dmar_header header;
+       uint8_t flags;
+       uint8_t reserved;
+       uint16_t segment;
+};
+
 
/*******************************************************************************
  *
  * HPET - High Precision Event Timer table