include, block: add krun_add_disk3 API

include/libkrun.h

@@ -217,6 +217,22 @@ int32_t krun_add_disk2(uint32_t ctx_id,
                        uint32_t disk_format,
                        bool read_only);
 
+
+ #define KRUN_SYNC_NONE 0;
+ #define KRUN_SYNC_RELAXED 1;
+ #define KRUN_SYNC_FULL 2;
+
+ #define KRUN_UNCACHED 0;
+ #define KRUN_CACHED 1;
+
+ int32_t krun_add_disk3(uint32_t ctx_id,
+                       const char *block_id,
+                       const char *disk_path,
+                       uint32_t disk_format,
+                       bool read_only,
+                       uint32_t cache_mode,
+                       uint32_t sync_mode);
+
 /**
  * NO LONGER SUPPORTED. DO NOT USE.
  *

src/devices/src/virtio/block/device.rs

@@ -35,7 +35,10 @@ use super::{
     Error, QUEUE_SIZES, SECTOR_SHIFT, SECTOR_SIZE,
 };
 
-use crate::virtio::{block::ImageType, ActivateError, InterruptTransport};
+use crate::virtio::{
+    block::{CacheMode, ImageType, SyncMode},
+    ActivateError, InterruptTransport,
+};
 
 /// Configuration options for disk caching.
 #[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
@@ -208,6 +211,9 @@ impl Block {
         disk_image_path: String,
         disk_image_format: ImageType,
         is_disk_read_only: bool,
+        // TODO(jakecorrenti): should this even be here? Am i just re-writing essentially what's represented by `CacheType`?
+        cache_mode: CacheMode,
+        sync_mode: SyncMode,
     ) -> io::Result<Block> {
         let disk_image = OpenOptions::new()
             .read(true)
@@ -218,7 +224,10 @@ impl Block {
 
         let file_opts = StorageOpenOptions::new()
             .write(!is_disk_read_only)
-            .filename(disk_image_path);
+            .filename(disk_image_path)
+            .direct(cache_mode == CacheMode::Uncached);
+
+        // TODO(jakecorrenti): how do I do a partial fsync on linux to handle that OS?
         #[cfg(target_os = "macos")]
         let file_opts = file_opts.relaxed_sync(true);
         let file = ImagoFile::open_sync(file_opts)?;
@@ -248,10 +257,14 @@ impl Block {
             DiskProperties::new(Arc::clone(&disk_image), disk_image_id.clone(), cache_type)?;
 
         let mut avail_features = (1u64 << VIRTIO_F_VERSION_1)
-            | (1u64 << VIRTIO_BLK_F_FLUSH)
+            // | (1u64 << VIRTIO_BLK_F_FLUSH)
             | (1u64 << VIRTIO_BLK_F_SEG_MAX)
             | (1u64 << VIRTIO_RING_F_EVENT_IDX);
 
+        if sync_mode != SyncMode::None {
+            avail_features |= 1u64 << VIRTIO_BLK_F_FLUSH;
+        }
+
         if is_disk_read_only {
             avail_features |= 1u64 << VIRTIO_BLK_F_RO;
         };

src/devices/src/virtio/block/mod.rs

@@ -39,3 +39,18 @@ pub enum ImageType {
     Raw,
     Qcow2,
 }
+
+#[derive(Clone, Debug, Default, PartialEq, Eq)]
+pub enum CacheMode {
+    Uncached,
+    #[default]
+    Cached,
+}
+
+#[derive(Clone, Debug, Default, PartialEq, Eq)]
+pub enum SyncMode {
+    None,
+    Relaxed,
+    #[default]
+    Full,
+}

src/libkrun/src/lib.rs

@@ -3,7 +3,7 @@ extern crate log;
 
 use crossbeam_channel::unbounded;
 #[cfg(feature = "blk")]
-use devices::virtio::block::ImageType;
+use devices::virtio::block::{CacheMode, ImageType, SyncMode};
 #[cfg(feature = "gpu")]
 use devices::virtio::gpu::display::DisplayInfo;
 #[cfg(feature = "net")]
@@ -671,6 +671,8 @@ pub unsafe extern "C" fn krun_add_disk(
                 disk_image_path: disk_path.to_string(),
                 disk_image_format: ImageType::Raw,
                 is_disk_read_only: read_only,
+                cache_mode: CacheMode::Cached,
+                sync_mode: SyncMode::Full,
             };
             cfg.add_block_cfg(block_device_config);
         }
@@ -718,6 +720,78 @@ pub unsafe extern "C" fn krun_add_disk2(
                 disk_image_path: disk_path.to_string(),
                 disk_image_format: format,
                 is_disk_read_only: read_only,
+                cache_mode: CacheMode::Cached,
+                sync_mode: SyncMode::Full,
+            };
+            cfg.add_block_cfg(block_device_config);
+        }
+        Entry::Vacant(_) => return -libc::ENOENT,
+    }
+
+    KRUN_SUCCESS
+}
+
+#[allow(clippy::missing_safety_doc)]
+#[no_mangle]
+#[cfg(feature = "blk")]
+pub unsafe extern "C" fn krun_add_disk3(
+    ctx_id: u32,
+    c_block_id: *const c_char,
+    c_disk_path: *const c_char,
+    disk_format: u32,
+    read_only: bool,
+    cache_mode: u32,
+    sync_mode: u32,
+) -> i32 {
+    let disk_path = match CStr::from_ptr(c_disk_path).to_str() {
+        Ok(disk) => disk,
+        Err(_) => return -libc::EINVAL,
+    };
+
+    let block_id = match CStr::from_ptr(c_block_id).to_str() {
+        Ok(block_id) => block_id,
+        Err(_) => return -libc::EINVAL,
+    };
+
+    let format = match disk_format {
+        0 => ImageType::Raw,
+        1 => ImageType::Qcow2,
+        _ => {
+            // Do not continue if the user cannot specify a valid disk format
+            return -libc::EINVAL;
+        }
+    };
+
+    let cache_mode = match cache_mode {
+        0 => CacheMode::Uncached,
+        1 => CacheMode::Cached,
+        _ => {
+            // Do not continue if the user cannot specify a valid cache mode
+            return -libc::EINVAL;
+        }
+    };
+
+    let sync_mode = match sync_mode {
+        0 => SyncMode::None,
+        1 => SyncMode::Relaxed,
+        2 => SyncMode::Full,
+        _ => {
+            // Do not continue if the user cannot specify a valid sync mode
+            return -libc::EINVAL;
+        }
+    };
+
+    match CTX_MAP.lock().unwrap().entry(ctx_id) {
+        Entry::Occupied(mut ctx_cfg) => {
+            let cfg = ctx_cfg.get_mut();
+            let block_device_config = BlockDeviceConfig {
+                block_id: block_id.to_string(),
+                cache_type: CacheType::auto(disk_path),
+                disk_image_path: disk_path.to_string(),
+                disk_image_format: format,
+                is_disk_read_only: read_only,
+                cache_mode,
+                sync_mode,
             };
             cfg.add_block_cfg(block_device_config);
         }
@@ -745,6 +819,8 @@ pub unsafe extern "C" fn krun_set_root_disk(ctx_id: u32, c_disk_path: *const c_c
                 disk_image_path: disk_path.to_string(),
                 disk_image_format: ImageType::Raw,
                 is_disk_read_only: false,
+                cache_mode: CacheMode::Cached,
+                sync_mode: SyncMode::Full,
             };
             cfg.set_root_block_cfg(block_device_config);
         }
@@ -772,6 +848,8 @@ pub unsafe extern "C" fn krun_set_data_disk(ctx_id: u32, c_disk_path: *const c_c
                 disk_image_path: disk_path.to_string(),
                 disk_image_format: ImageType::Raw,
                 is_disk_read_only: false,
+                cache_mode: CacheMode::Cached,
+                sync_mode: SyncMode::Full,
             };
             cfg.set_data_block_cfg(block_device_config);
         }

src/vmm/src/vmm_config/block.rs

@@ -2,7 +2,10 @@ use std::collections::VecDeque;
 use std::fmt;
 use std::sync::{Arc, Mutex};
 
-use devices::virtio::{block::ImageType, Block, CacheType};
+use devices::virtio::{
+    block::{CacheMode, ImageType, SyncMode},
+    Block, CacheType,
+};
 
 #[derive(Debug)]
 pub enum BlockConfigError {
@@ -28,6 +31,8 @@ pub struct BlockDeviceConfig {
     pub disk_image_path: String,
     pub disk_image_format: ImageType,
     pub is_disk_read_only: bool,
+    pub cache_mode: CacheMode,
+    pub sync_mode: SyncMode,
 }
 
 #[derive(Clone, Debug, Eq, PartialEq)]
@@ -63,6 +68,8 @@ impl BlockBuilder {
             config.disk_image_path,
             config.disk_image_format,
             config.is_disk_read_only,
+            config.cache_mode,
+            config.sync_mode,
         )
         .map_err(BlockConfigError::CreateBlockDevice)
     }