Check KMD version prior to querying device info

device/pcie/pci_device.cpp

@@ -37,6 +37,38 @@ static const uint32_t BH_BAR0_WC_MAPPING_SIZE = 188<<21;
 static const uint32_t BH_NOC_NODE_ID_OFFSET = 0x1FD04044;
 static const uint32_t GS_WH_ARC_SCRATCH_6_OFFSET = 0x1FF30078;
 
+static constexpr semver_t MINIMUM_SUPPORTED_KMD_VERSION{1, 27, 1};
+
+static semver_t read_kmd_version() {
+    static const std::string path = "/sys/module/tenstorrent/version";
+    std::ifstream file(path);
+
+    if (!file.is_open()) {
+       TT_THROW("Failed to open: {}; could not determine tenstorrent driver version", path);
+    }
+
+    std::string version_str;
+    std::getline(file, version_str);
+
+    std::istringstream iss(version_str);
+    std::string token;
+    semver_t semver{};
+
+    if (std::getline(iss, token, '.')) {
+        semver.major = std::stoul(token);
+
+        if (std::getline(iss, token, '.')) {
+            semver.minor = std::stoul(token);
+
+            if (std::getline(iss, token, '.')) {
+                semver.patch = std::stoul(token);
+            }
+        }
+    }
+
+    return semver;
+}
+
 template <typename T>
 static T read_sysfs(const PciDeviceInfo &device_info, const std::string &attribute_name) {
     const auto sysfs_path = fmt::format("/sys/bus/pci/devices/{:04x}:{:02x}:{:02x}.{:x}/{}",
@@ -68,6 +100,12 @@ static T read_sysfs(const PciDeviceInfo &device_info, const std::string &attribu
 
 static PciDeviceInfo read_device_info(int fd)
 {
+    const semver_t kmd_version = read_kmd_version();
+    if (kmd_version < MINIMUM_SUPPORTED_KMD_VERSION) {
+        TT_THROW("Unsupported tenstorrent driver version: {}.  Please upgrade to at least {}.",
+                 kmd_version.to_string(), MINIMUM_SUPPORTED_KMD_VERSION.to_string());
+    }
+
     tenstorrent_get_device_info info{};
     info.in.output_size_bytes = sizeof(info.out);
 

device/pcie/pci_device.hpp

@@ -43,11 +43,51 @@ struct PciDeviceInfo
     uint16_t pci_function;
 };
 
+// TODO: probably belongs in common.hpp
+struct semver_t {
+    uint32_t major;
+    uint32_t minor;
+    uint32_t patch;
+
+    // TODO: there's a neater, C++20 way to do these comparisons.
+    // Start using it once we move off of Ubuntu 20.04 to a distro that ships a
+    // modern compiler.
+
+    bool operator<(const semver_t& other) const {
+        return std::tie(major, minor, patch) < std::tie(other.major, other.minor, other.patch);
+    }
+
+    bool operator>(const semver_t& other) const {
+        return other < *this;
+    }
+
+    bool operator==(const semver_t& other) const {
+        return std::tie(major, minor, patch) == std::tie(other.major, other.minor, other.patch);
+    }
+
+    bool operator!=(const semver_t& other) const {
+        return !(*this == other);
+    }
+
+    bool operator<=(const semver_t& other) const {
+        return !(other < *this);
+    }
+
+    bool operator>=(const semver_t& other) const {
+        return !(*this < other);
+    }
+
+    std::string to_string() const {
+        return std::to_string(major) + "." + std::to_string(minor) + "." + std::to_string(patch);
+    }
+};
+
+
 class PCIDevice {
     const std::string device_path;  // Path to character device: /dev/tenstorrent/N
-    const int pci_device_num;           // N in /dev/tenstorrent/N
+    const int pci_device_num;       // N in /dev/tenstorrent/N
     const int logical_id;           // Unique identifier for each device in entire network topology
-    const int pci_device_file_desc;                   // Character device file descriptor
+    const int pci_device_file_desc; // Character device file descriptor
     const PciDeviceInfo info;       // PCI device info
     const int numa_node;            // -1 if non-NUMA
     const int revision;             // PCI revision value from sysfs