From a886f99a000aa470b4aa874be7842bcfcbe81216 Mon Sep 17 00:00:00 2001
From: Alex Lyn <alex.lyn@antgroup.com>
Date: Mon, 13 Jul 2026 11:36:45 +0800
Subject: [PATCH] runtime-rs: Map and propagate block discard to CH sparse
 disks

Add the Cloud Hypervisor disk sparse option to the local DiskConfig
model and keep its default aligned with upstream. Map
BlockConfigModern.discard_unmap to DiskConfig.sparse so block devices
that request discard/unmap explicitly expose sparse discard support
through the CH API.

Signed-off-by: Alex Lyn <alex.lyn@antgroup.com>
---
 .../crates/hypervisor/ch-config/src/lib.rs    | 29 ++++++++++++++++++-
 .../crates/hypervisor/src/ch/inner_device.rs  |  1 +
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/src/runtime-rs/crates/hypervisor/ch-config/src/lib.rs b/src/runtime-rs/crates/hypervisor/ch-config/src/lib.rs
index 2fb2fcceb6..75cf0ba0d9 100644
--- a/src/runtime-rs/crates/hypervisor/ch-config/src/lib.rs
+++ b/src/runtime-rs/crates/hypervisor/ch-config/src/lib.rs
@@ -123,7 +123,7 @@ pub enum ImageType {
     Unknown,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Deserialize, Serialize, Default)]
+#[derive(Clone, Debug, PartialEq, Eq, Deserialize, Serialize)]
 pub struct DiskConfig {
     pub path: Option<PathBuf>,
     #[serde(default)]
@@ -148,10 +148,37 @@ pub struct DiskConfig {
     pub disable_io_uring: bool,
     #[serde(default)]
     pub pci_segment: u16,
+    #[serde(default = "default_diskconfig_sparse")]
+    pub sparse: bool,
     #[serde(default)]
     pub image_type: ImageType,
 }
 
+pub fn default_diskconfig_sparse() -> bool {
+    true
+}
+
+impl Default for DiskConfig {
+    fn default() -> Self {
+        Self {
+            path: None,
+            readonly: false,
+            direct: false,
+            iommu: false,
+            num_queues: 0,
+            queue_size: 0,
+            vhost_user: false,
+            vhost_socket: None,
+            rate_limiter_config: None,
+            id: None,
+            disable_io_uring: false,
+            pci_segment: 0,
+            sparse: default_diskconfig_sparse(),
+            image_type: ImageType::default(),
+        }
+    }
+}
+
 #[derive(Clone, Debug, PartialEq, Eq, Deserialize, Serialize, Default)]
 pub struct FsConfig {
     pub tag: String,
diff --git a/src/runtime-rs/crates/hypervisor/src/ch/inner_device.rs b/src/runtime-rs/crates/hypervisor/src/ch/inner_device.rs
index f988a64e0d..399981ed85 100644
--- a/src/runtime-rs/crates/hypervisor/src/ch/inner_device.rs
+++ b/src/runtime-rs/crates/hypervisor/src/ch/inner_device.rs
@@ -522,6 +522,7 @@ impl TryFrom<BlockConfigModern> for DiskConfig {
             readonly: blkcfg.is_readonly,
             num_queues: blkcfg.num_queues,
             queue_size: blkcfg.queue_size as u16,
+            sparse: blkcfg.discard_unmap,
             image_type: ImageType::Raw,
             ..Default::default()
         };