diff --git a/graphics/composer/2.4/IComposerClient.hal b/graphics/composer/2.4/IComposerClient.hal
index 7e0c33c..9e3cf0e 100644
--- a/graphics/composer/2.4/IComposerClient.hal
+++ b/graphics/composer/2.4/IComposerClient.hal
@@ -71,6 +71,51 @@
          *   setClientTargetProperty(ClientTargetProperty clientTargetProperty);
          */
          SET_CLIENT_TARGET_PROPERTY = 0x105 << @2.1::IComposerClient.Command:OPCODE_SHIFT,
+
+        /**
+         * SET_LAYER_GENERIC_METADATA has this pseudo prototype
+         *
+         *   setLayerGenericMetadata(string key, bool mandatory, vec<uint8_t> value);
+         *
+         * Sets a piece of generic metadata for the given layer. If this
+         * function is called twice with the same key but different values, the
+         * newer value must override the older one. Calling this function with a
+         * 0-length value must reset that key's metadata as if it had not been
+         * set.
+         *
+         * A given piece of metadata may either be mandatory or a hint
+         * (non-mandatory) as indicated by the second parameter. Mandatory
+         * metadata may affect the composition result, which is to say that it
+         * may cause a visible change in the final image. By contrast, hints may
+         * only affect the composition strategy, such as which layers are
+         * composited by the client, but must not cause a visible change in the
+         * final image. The value of the mandatory flag shall match the value
+         * returned from getLayerGenericMetadataKeys for the given key.
+         *
+         * Only keys which have been returned from getLayerGenericMetadataKeys()
+         * shall be accepted. Any other keys must result in an UNSUPPORTED error.
+         *
+         * The value passed into this function shall be the binary
+         * representation of a HIDL type corresponding to the given key. For
+         * example, a key of 'com.example.V1_3.Foo' shall be paired with a
+         * value of type com.example@1.3::Foo, which would be defined in a
+         * vendor HAL extension.
+         *
+         * This function will be encoded in the command buffer in this order:
+         *   1) The key length, stored as a uint32_t
+         *   2) The key itself, padded to a uint32_t boundary if necessary
+         *   3) The mandatory flag, stored as a uint32_t
+         *   4) The value length in bytes, stored as a uint32_t
+         *   5) The value itself, padded to a uint32_t boundary if necessary
+         *
+         * @param key indicates which metadata value should be set on this layer
+         * @param mandatory indicates whether this particular key represents
+         *        mandatory metadata or a hint (non-mandatory metadata), as
+         *        described above
+         * @param value is a binary representation of a HIDL struct
+         *        corresponding to the key as described above
+         */
+        SET_LAYER_GENERIC_METADATA = 0x40e << @2.1::IComposerClient.Command:OPCODE_SHIFT,
     };
 
     /**
@@ -271,4 +316,33 @@
      */
     setContentType(Display display, ContentType type)
         generates (Error error);
+
+    struct LayerGenericMetadataKey {
+        /**
+         * Key names must comply with the requirements specified for
+         * getLayerGenericMetadataKeys below
+         */
+        string name;
+
+        /**
+         * The mandatory flag is defined in the description of
+         * setLayerGenericMetadata above
+         */
+        bool mandatory;
+    };
+
+    /**
+     * Retrieves the set of keys that may be passed into setLayerGenericMetadata
+     *
+     * Key names must meet the following requirements:
+     * - Must be specified in reverse domain name notation
+     * - Must not start with 'com.android' or 'android'
+     * - Must be unique within the returned vector
+     * - Must correspond to a matching HIDL struct type, which defines the
+     *   structure of its values. For example, the key 'com.example.V1-3.Foo'
+     *   should correspond to a value of type com.example@1.3::Foo, which is
+     *   defined in a vendor HAL extension
+     */
+    getLayerGenericMetadataKeys()
+        generates(Error error, vec<LayerGenericMetadataKey> keys);
 };
diff --git a/graphics/composer/2.4/utils/command-buffer/include/composer-command-buffer/2.4/ComposerCommandBuffer.h b/graphics/composer/2.4/utils/command-buffer/include/composer-command-buffer/2.4/ComposerCommandBuffer.h
index e84779e..eb35e5c 100644
--- a/graphics/composer/2.4/utils/command-buffer/include/composer-command-buffer/2.4/ComposerCommandBuffer.h
+++ b/graphics/composer/2.4/utils/command-buffer/include/composer-command-buffer/2.4/ComposerCommandBuffer.h
@@ -53,6 +53,27 @@
         writeSigned(static_cast<int32_t>(clientTargetProperty.dataspace));
         endCommand();
     }
+
+    void setLayerGenericMetadata(const hidl_string& key, const bool mandatory,
+                                 const hidl_vec<uint8_t>& value) {
+        const size_t commandSize = 3 + sizeToElements(key.size()) + sizeToElements(value.size());
+        if (commandSize > std::numeric_limits<uint16_t>::max()) {
+            LOG_FATAL("Too much generic metadata (%zu elements)", commandSize);
+            return;
+        }
+
+        beginCommand(IComposerClient::Command::SET_LAYER_GENERIC_METADATA,
+                     static_cast<uint16_t>(commandSize));
+        write(key.size());
+        writeBlob(key.size(), reinterpret_cast<const unsigned char*>(key.c_str()));
+        write(mandatory);
+        write(value.size());
+        writeBlob(value.size(), value.data());
+        endCommand();
+    }
+
+  protected:
+    uint32_t sizeToElements(uint32_t size) { return (size + 3) / 4; }
 };
 
 // This class helps parse a command queue.  Note that all sizes/lengths are in
diff --git a/graphics/composer/2.4/utils/hal/include/composer-hal/2.4/ComposerClient.h b/graphics/composer/2.4/utils/hal/include/composer-hal/2.4/ComposerClient.h
index c864ce6..c889069 100644
--- a/graphics/composer/2.4/utils/hal/include/composer-hal/2.4/ComposerClient.h
+++ b/graphics/composer/2.4/utils/hal/include/composer-hal/2.4/ComposerClient.h
@@ -164,6 +164,14 @@
         return mHal->setContentType(display, contentType);
     }
 
+    Return<void> getLayerGenericMetadataKeys(
+            IComposerClient::getLayerGenericMetadataKeys_cb hidl_cb) override {
+        std::vector<IComposerClient::LayerGenericMetadataKey> keys;
+        Error error = mHal->getLayerGenericMetadataKeys(&keys);
+        hidl_cb(error, keys);
+        return Void();
+    }
+
     static std::unique_ptr<ComposerClientImpl> create(Hal* hal) {
         auto client = std::make_unique<ComposerClientImpl>(hal);
         return client->init() ? std::move(client) : nullptr;
diff --git a/graphics/composer/2.4/utils/hal/include/composer-hal/2.4/ComposerCommandEngine.h b/graphics/composer/2.4/utils/hal/include/composer-hal/2.4/ComposerCommandEngine.h
index e0153ce..697d6b8 100644
--- a/graphics/composer/2.4/utils/hal/include/composer-hal/2.4/ComposerCommandEngine.h
+++ b/graphics/composer/2.4/utils/hal/include/composer-hal/2.4/ComposerCommandEngine.h
@@ -74,6 +74,43 @@
 
     CommandWriterBase* getWriter() { return static_cast<CommandWriterBase*>(mWriter.get()); }
 
+    bool executeCommand(V2_1::IComposerClient::Command command, uint16_t length) override {
+        switch (static_cast<IComposerClient::Command>(command)) {
+            case IComposerClient::Command::SET_LAYER_GENERIC_METADATA:
+                return executeSetLayerGenericMetadata(length);
+            default:
+                return BaseType2_3::executeCommand(command, length);
+        }
+    }
+
+    bool executeSetLayerGenericMetadata(uint16_t length) {
+        // We expect at least two buffer lengths and a mandatory flag
+        if (length < 3) {
+            return false;
+        }
+
+        const uint32_t keySize = read();
+        std::string key;
+        key.resize(keySize);
+        readBlob(keySize, key.data());
+
+        const bool mandatory = read();
+
+        const uint32_t valueSize = read();
+        std::vector<uint8_t> value(valueSize);
+        readBlob(valueSize, value.data());
+
+        auto error = mHal->setLayerGenericMetadata(mCurrentDisplay, mCurrentLayer, key, mandatory,
+                                                   value);
+        if (error != Error::NONE) {
+            // The error cast is safe because setLayerGenericMetadata doesn't
+            // return any of the new values added in V2_4::Error
+            mWriter->setError(getCommandLoc(), static_cast<V2_1::Error>(error));
+        }
+
+        return true;
+    }
+
     ComposerHal* mHal;
 };
 
diff --git a/graphics/composer/2.4/utils/hal/include/composer-hal/2.4/ComposerHal.h b/graphics/composer/2.4/utils/hal/include/composer-hal/2.4/ComposerHal.h
index 277055c..58991c1 100644
--- a/graphics/composer/2.4/utils/hal/include/composer-hal/2.4/ComposerHal.h
+++ b/graphics/composer/2.4/utils/hal/include/composer-hal/2.4/ComposerHal.h
@@ -79,6 +79,10 @@
             uint32_t* outDisplayRequestMask, std::vector<Layer>* outRequestedLayers,
             std::vector<uint32_t>* outRequestMasks,
             IComposerClient::ClientTargetProperty* outClientTargetProperty) = 0;
+    virtual Error setLayerGenericMetadata(Display display, Layer layer, const std::string& key,
+                                          bool mandatory, const std::vector<uint8_t>& value) = 0;
+    virtual Error getLayerGenericMetadataKeys(
+            std::vector<IComposerClient::LayerGenericMetadataKey>* outKeys) = 0;
 };
 
 }  // namespace hal
diff --git a/graphics/composer/2.4/utils/passthrough/include/composer-passthrough/2.4/HwcHal.h b/graphics/composer/2.4/utils/passthrough/include/composer-passthrough/2.4/HwcHal.h
index 616852a..d28e006 100644
--- a/graphics/composer/2.4/utils/passthrough/include/composer-passthrough/2.4/HwcHal.h
+++ b/graphics/composer/2.4/utils/passthrough/include/composer-passthrough/2.4/HwcHal.h
@@ -245,6 +245,61 @@
         return err;
     }
 
+    Error setLayerGenericMetadata(Display display, Layer layer, const std::string& key,
+                                  bool mandatory, const std::vector<uint8_t>& value) override {
+        if (!mDispatch.setLayerGenericMetadata) {
+            return Error::UNSUPPORTED;
+        }
+
+        if (key.size() > std::numeric_limits<uint32_t>::max()) {
+            return Error::BAD_PARAMETER;
+        }
+
+        if (value.size() > std::numeric_limits<uint32_t>::max()) {
+            return Error::BAD_PARAMETER;
+        }
+
+        int32_t error = mDispatch.setLayerGenericMetadata(
+                mDevice, display, layer, static_cast<uint32_t>(key.size()), key.c_str(), mandatory,
+                static_cast<uint32_t>(value.size()), value.data());
+        return static_cast<Error>(error);
+    }
+
+    Error getLayerGenericMetadataKeys(
+            std::vector<IComposerClient::LayerGenericMetadataKey>* outKeys) override {
+        if (!mDispatch.getLayerGenericMetadataKey) {
+            return Error::UNSUPPORTED;
+        }
+
+        std::vector<IComposerClient::LayerGenericMetadataKey> keys;
+
+        uint32_t index = 0;
+        uint32_t keyLength = 0;
+        while (true) {
+            mDispatch.getLayerGenericMetadataKey(mDevice, index, &keyLength, nullptr, nullptr);
+            if (keyLength == 0) {
+                break;
+            }
+
+            IComposerClient::LayerGenericMetadataKey key;
+            std::string keyName;
+            keyName.resize(keyLength);
+            mDispatch.getLayerGenericMetadataKey(mDevice, index, &keyLength, keyName.data(),
+                                                 &key.mandatory);
+            key.name = keyName;
+            keys.emplace_back(std::move(key));
+
+            // Only attempt to load the first 100 keys to avoid an infinite loop
+            // if something goes wrong
+            if (++index > 100) {
+                break;
+            }
+        }
+
+        *outKeys = std::move(keys);
+        return Error::NONE;
+    }
+
   protected:
     bool initDispatch() override {
         if (!BaseType2_3::initDispatch()) {
@@ -267,6 +322,11 @@
         this->initOptionalDispatch(HWC2_FUNCTION_SET_CONTENT_TYPE, &mDispatch.setContentType);
         this->initOptionalDispatch(HWC2_FUNCTION_GET_CLIENT_TARGET_PROPERTY,
                                    &mDispatch.getClientTargetProperty);
+        this->initOptionalDispatch(HWC2_FUNCTION_SET_LAYER_GENERIC_METADATA,
+                                   &mDispatch.setLayerGenericMetadata);
+        this->initOptionalDispatch(HWC2_FUNCTION_GET_LAYER_GENERIC_METADATA_KEY,
+                                   &mDispatch.getLayerGenericMetadataKey);
+
         return true;
     }
 
@@ -319,6 +379,8 @@
         HWC2_PFN_GET_SUPPORTED_CONTENT_TYPES getSupportedContentTypes;
         HWC2_PFN_SET_CONTENT_TYPE setContentType;
         HWC2_PFN_GET_CLIENT_TARGET_PROPERTY getClientTargetProperty;
+        HWC2_PFN_SET_LAYER_GENERIC_METADATA setLayerGenericMetadata;
+        HWC2_PFN_GET_LAYER_GENERIC_METADATA_KEY getLayerGenericMetadataKey;
     } mDispatch = {};
 
     hal::ComposerHal::EventCallback_2_4* mEventCallback_2_4 = nullptr;
diff --git a/graphics/composer/2.4/utils/vts/ComposerVts.cpp b/graphics/composer/2.4/utils/vts/ComposerVts.cpp
index 8a9c006..8cdc452 100644
--- a/graphics/composer/2.4/utils/vts/ComposerVts.cpp
+++ b/graphics/composer/2.4/utils/vts/ComposerVts.cpp
@@ -129,6 +129,16 @@
     return mClient->setContentType(display, contentType);
 }
 
+Error ComposerClient::getLayerGenericMetadataKeys(
+        std::vector<IComposerClient::LayerGenericMetadataKey>* outKeys) {
+    Error error = Error::NONE;
+    mClient->getLayerGenericMetadataKeys([&](const auto tmpError, const auto& tmpKeys) {
+        error = tmpError;
+        *outKeys = tmpKeys;
+    });
+    return error;
+}
+
 }  // namespace vts
 }  // namespace V2_4
 }  // namespace composer
diff --git a/graphics/composer/2.4/utils/vts/include/composer-vts/2.4/ComposerVts.h b/graphics/composer/2.4/utils/vts/include/composer-vts/2.4/ComposerVts.h
index df75a48..3dd8e50 100644
--- a/graphics/composer/2.4/utils/vts/include/composer-vts/2.4/ComposerVts.h
+++ b/graphics/composer/2.4/utils/vts/include/composer-vts/2.4/ComposerVts.h
@@ -93,6 +93,9 @@
 
     Error setContentType(Display display, IComposerClient::ContentType contentType);
 
+    Error getLayerGenericMetadataKeys(
+            std::vector<IComposerClient::LayerGenericMetadataKey>* outKeys);
+
   private:
     const sp<IComposerClient> mClient;
 };
diff --git a/graphics/composer/2.4/vts/functional/VtsHalGraphicsComposerV2_4TargetTest.cpp b/graphics/composer/2.4/vts/functional/VtsHalGraphicsComposerV2_4TargetTest.cpp
index 800ff08..f6b46ff 100644
--- a/graphics/composer/2.4/vts/functional/VtsHalGraphicsComposerV2_4TargetTest.cpp
+++ b/graphics/composer/2.4/vts/functional/VtsHalGraphicsComposerV2_4TargetTest.cpp
@@ -17,6 +17,7 @@
 #define LOG_TAG "graphics_composer_hidl_hal_test@2.4"
 
 #include <algorithm>
+#include <regex>
 #include <thread>
 
 #include <android-base/logging.h>
@@ -625,6 +626,28 @@
         testing::ValuesIn(android::hardware::getAllHalInstanceNames(IComposer::descriptor)),
         android::hardware::PrintInstanceNameToString);
 
+TEST_F(GraphicsComposerHidlCommandTest, getLayerGenericMetadataKeys) {
+    std::vector<IComposerClient::LayerGenericMetadataKey> keys;
+    mComposerClient->getLayerGenericMetadataKeys(&keys);
+
+    std::regex reverseDomainName("^[a-zA-Z-]{2,}(\\.[a-zA-Z0-9-]+)+$");
+    std::unordered_set<std::string> uniqueNames;
+    for (const auto& key : keys) {
+        std::string name(key.name.c_str());
+
+        // Keys must not start with 'android' or 'com.android'
+        ASSERT_FALSE(name.find("android") == 0);
+        ASSERT_FALSE(name.find("com.android") == 0);
+
+        // Keys must be in reverse domain name format
+        ASSERT_TRUE(std::regex_match(name, reverseDomainName));
+
+        // Keys must be unique within this list
+        const auto& [iter, inserted] = uniqueNames.insert(name);
+        ASSERT_TRUE(inserted);
+    }
+}
+
 }  // namespace
 }  // namespace vts
 }  // namespace V2_4