util: Introduce virAcpi module

The aim of this new module is to contain code that's parsing ACPI
tables. For now, only parsing of IORT table is implemented (it's
ARM specific table). And since we only need to check whether the
table contains SMMU record, the code is very simplified.
I've followed the specification published here:

  https://developer.arm.com/documentation/den0049/latest/

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>

po/POTFILES

@@ -244,6 +244,7 @@ src/storage_file/storage_source.c
 src/storage_file/storage_source_backingstore.c
 src/test/test_driver.c
 src/util/iohelper.c
+src/util/viracpi.c
 src/util/viralloc.c
 src/util/virarptable.c
 src/util/viraudit.c

src/libvirt_private.syms

@@ -1829,6 +1829,13 @@ vir_g_strdup_printf;
 vir_g_strdup_vprintf;
 
 
+# util/viracpi.c
+virAcpiHasSMMU;
+virAcpiParseIORT;
+virIORTNodeTypeTypeFromString;
+virIORTNodeTypeTypeToString;
+
+
 # util/viralloc.h
 virAppendElement;
 virDeleteElementsN;

src/util/meson.build

@@ -1,5 +1,6 @@
 util_sources = [
   'glibcompat.c',
+  'viracpi.c',
   'viralloc.c',
   'virarch.c',
   'virarptable.c',

src/util/viracpi.c

@@ -0,0 +1,225 @@
+/*
+ * viracpi.c: ACPI table(s) parser
+ *
+ * Copyright (C) 2023 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library;  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+
+#include <inttypes.h>
+#include <fcntl.h>
+
+#define LIBVIRT_VIRACPIPRIV_H_ALLOW
+#include "internal.h"
+#include "viracpi.h"
+#include "viracpipriv.h"
+#include "viralloc.h"
+#include "virerror.h"
+#include "virfile.h"
+#include "virlog.h"
+
+#define VIR_FROM_THIS VIR_FROM_NONE
+
+VIR_LOG_INIT("util.acpi");
+
+typedef struct virIORTHeader virIORTHeader;
+struct virIORTHeader {
+    uint32_t signature;
+    uint32_t length;
+    uint8_t revision;
+    uint8_t checksum;
+    char oem_id[6];
+    char oem_table_id[8];
+    char oem_revision[4];
+    char creator_id[4];
+    char creator_revision[4];
+    /* Technically, the following are not part of header, but
+     * they immediately follow the header and are in the table
+     * exactly once. */
+    uint32_t nnodes;
+    uint32_t nodes_offset;
+    /* Here follows reserved and padding fields. Ain't nobody's
+     * interested in that. */
+} ATTRIBUTE_PACKED;
+
+VIR_ENUM_IMPL(virIORTNodeType,
+              VIR_IORT_NODE_TYPE_LAST,
+              "ITS Group",
+              "Named Component",
+              "Root Complex",
+              "SMMUv1 or SMMUv2",
+              "SMMUv3",
+              "PMCG",
+              "Memory range");
+
+
+static int
+virAcpiParseIORTNodeHeader(int fd,
+                           const char *filename,
+                           virIORTNodeHeader *nodeHeader)
+{
+    g_autofree char *nodeHeaderBuf = NULL;
+    const char *typeStr = NULL;
+    int nodeHeaderLen;
+
+    nodeHeaderLen = virFileReadHeaderFD(fd, sizeof(*nodeHeader), &nodeHeaderBuf);
+    if (nodeHeaderLen < 0) {
+        virReportSystemError(errno,
+                             _("cannot read node header '%1$s'"),
+                             filename);
+        return -1;
+    }
+
+    if (nodeHeaderLen != sizeof(*nodeHeader)) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("IORT table node header ended early"));
+        return -1;
+    }
+
+    memcpy(nodeHeader, nodeHeaderBuf, nodeHeaderLen);
+
+    typeStr = virIORTNodeTypeTypeToString(nodeHeader->type);
+
+    VIR_DEBUG("IORT node header: type = %" PRIu8 " (%s) len = %" PRIu16,
+              nodeHeader->type, NULLSTR(typeStr), nodeHeader->len);
+
+    /* Basic sanity check. While there's a type specific data
+     * that follows the node header, the node length should be at
+     * least size of header itself. */
+    if (nodeHeader->len < sizeof(*nodeHeader)) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("IORT table node type %1$s has invalid length: got %2$u, expected at least %3$lu"),
+                       NULLSTR(typeStr), (unsigned int)nodeHeader->len, sizeof(*nodeHeader));
+        return -1;
+    }
+    return 0;
+}
+
+
+static ssize_t
+virAcpiParseIORTNodes(int fd,
+                      const char *filename,
+                      const virIORTHeader *header,
+                      virIORTNodeHeader **nodesRet)
+{
+    g_autofree virIORTNodeHeader *nodes = NULL;
+    size_t nnodes = 0;
+    off_t pos;
+
+    /* Firstly, reset position to the start of nodes. */
+    if ((pos = lseek(fd, header->nodes_offset, SEEK_SET)) < 0) {
+        virReportSystemError(errno,
+                             _("cannot seek in '%1$s'"),
+                             filename);
+        return -1;
+    }
+
+    for (; pos < header->length;) {
+        virIORTNodeHeader node;
+
+        if (virAcpiParseIORTNodeHeader(fd, filename, &node) < 0)
+            return -1;
+
+        if ((pos = lseek(fd, pos + node.len, SEEK_SET)) < 0) {
+            virReportSystemError(errno,
+                                 _("cannot seek in '%1$s'"),
+                                 filename);
+            return -1;
+        }
+
+        VIR_APPEND_ELEMENT(nodes, nnodes, node);
+    }
+
+    *nodesRet = g_steal_pointer(&nodes);
+    return nnodes;
+}
+
+
+ssize_t
+virAcpiParseIORT(virIORTNodeHeader **nodesRet,
+                 const char *filename)
+{
+    VIR_AUTOCLOSE fd = -1;
+    g_autofree char *headerBuf = NULL;
+    int headerLen;
+    virIORTHeader header;
+
+    if ((fd = open(filename, O_RDONLY)) < 0) {
+        virReportSystemError(errno,
+                             _("cannot open '%1$s'"),
+                             filename);
+        return -1;
+    }
+
+    headerLen = virFileReadHeaderFD(fd, sizeof(header), &headerBuf);
+    if (headerLen < 0) {
+        virReportSystemError(errno,
+                             _("cannot read header '%1$s'"),
+                             filename);
+        return -1;
+    }
+
+    if (headerLen != sizeof(header)) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("IORT table header ended early"));
+        return -1;
+    }
+
+    memcpy(&header, headerBuf, headerLen);
+
+    VIR_DEBUG("IORT header: len = %" PRIu32 " revision = %" PRIu8
+              " nnodes = %" PRIu32 " OEM = %s",
+              header.length, header.revision,
+              header.nnodes, header.oem_id);
+
+    return virAcpiParseIORTNodes(fd, filename, &header, nodesRet);
+}
+
+
+#define IORT_PATH "/sys/firmware/acpi/tables/IORT"
+
+/**
+ * virAcpiHasSMMU:
+ *
+ * Parse IORT table trying to find SMMU node entry.
+ * Since IORT is ARM specific ACPI table, it doesn't make much
+ * sense to call this function on other platforms and expect
+ * sensible result.
+ *
+ * Returns: 0 if no SMMU node was found,
+ *          1 if a SMMU node was found (i.e. host supports SMMU),
+ *         -1 otherwise (with error reported).
+ */
+int
+virAcpiHasSMMU(void)
+{
+    g_autofree virIORTNodeHeader *nodes = NULL;
+    ssize_t nnodes = -1;
+    size_t i;
+
+    if ((nnodes = virAcpiParseIORT(&nodes, IORT_PATH)) < 0)
+        return -1;
+
+    for (i = 0; i < nnodes; i++) {
+        if (nodes[i].type == VIR_IORT_NODE_TYPE_SMMUV1_OR_SMMUV2 ||
+            nodes[i].type == VIR_IORT_NODE_TYPE_SMMUV3) {
+            return 1;
+        }
+    }
+
+    return 0;
+}

src/util/viracpi.h

@@ -0,0 +1,23 @@
+/*
+ * viracpi.h: ACPI table(s) parser
+ *
+ * Copyright (C) 2023 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library;  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+int virAcpiHasSMMU(void);

src/util/viracpipriv.h

@@ -0,0 +1,58 @@
+/*
+ * viracpipriv.h: Functions for testing virAcpi APIs
+ *
+ * Copyright (C) 2023 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef LIBVIRT_VIRACPIPRIV_H_ALLOW
+# error "viracpipriv.h may only be included by viracpi.c or test suites"
+#endif /* LIBVIRT_VIRACPIPRIV_H_ALLOW */
+
+#pragma once
+
+#include <inttypes.h>
+
+#include "internal.h"
+#include "virenum.h"
+
+typedef enum {
+    VIR_IORT_NODE_TYPE_ITS_GROUP = 0,
+    VIR_IORT_NODE_TYPE_NAMED_COMPONENT,
+    VIR_IORT_NODE_TYPE_ROOT_COMPLEX,
+    VIR_IORT_NODE_TYPE_SMMUV1_OR_SMMUV2,
+    VIR_IORT_NODE_TYPE_SMMUV3,
+    VIR_IORT_NODE_TYPE_PMCG,
+    VIR_IORT_NODE_TYPE_MEMORY_RANGE,
+    VIR_IORT_NODE_TYPE_LAST,
+} virIORTNodeType;
+
+VIR_ENUM_DECL(virIORTNodeType);
+
+typedef struct virIORTNodeHeader virIORTNodeHeader;
+struct virIORTNodeHeader {
+    uint8_t type; /* One of virIORTNodeType */
+    uint16_t len;
+    uint8_t revision;
+    uint32_t identifier;
+    uint32_t nmappings;
+    uint32_t reference_id;
+} ATTRIBUTE_PACKED;
+
+ssize_t
+virAcpiParseIORT(virIORTNodeHeader **nodesRet,
+                 const char *filename);