Add experimental Computational Storage Drive mode

README.md

@@ -31,6 +31,7 @@
   - [WhiteBox SSD Mode (OCSSD)](#whitebox-ssd-mode-ocssd)
   - [Zoned Namespace SSD Mode (ZNSSD)](#zoned-namespace-ssd-mode-znssd)
   - [NoSSD Mode](#nossd-mode)
+  - [Computational Storage Mode (CSD)](#computational-storage-mode-csd)
 - [Configuration](#configuration)
 - [Development](#development)
 - [Troubleshooting](#troubleshooting)
@@ -62,12 +63,12 @@ FEMU bridges the gap between SSD hardware platforms and SSD simulators by provid
 
 ## Features
 
-| Feature | BlackBox | WhiteBox | ZNS | NoSSD |
-|---------|----------|----------|-----|--------|
-| **FTL Management** | Device-side | Host-side | Zone-based | None |
-| **Use Cases** | Commercial SSD simulation | OpenChannel SSD research | ZNS research | SCM emulation |
-| **Latency Model** | Realistic NAND | Realistic NAND | Zone-optimized | Ultra-low (sub-10μs) |
-| **Guest Support** | Full NVMe | OpenChannel 1.2/2.0 | NVMe ZNS | NVMe basic |
+| Feature | BlackBox | WhiteBox | ZNS | NoSSD | CSD |
+|---------|----------|----------|-----|--------|-----|
+| **FTL Management** | Device-side | Host-side | Zone-based | None | Device-side |
+| **Use Cases** | Commercial SSD simulation | OpenChannel SSD research | ZNS research | SCM emulation | Computational storage research |
+| **Latency Model** | Realistic NAND | Realistic NAND | Zone-optimized | Ultra-low (sub-10μs) | Realistic NAND + compute runtime |
+| **Guest Support** | Full NVMe | OpenChannel 1.2/2.0 | NVMe ZNS | NVMe basic | Full NVMe + CSD commands |
 
 ---
 
@@ -367,6 +368,42 @@ Ultra-fast NVMe emulation without storage logic.
 - Performance upper-bound testing
 - Fast storage prototyping
 
+### Computational Storage Mode (CSD)
+
+Experimental computational storage support derived from CEMU. CSD is selected
+with `femu_mode=4` and keeps CSD-specific code under `hw/femu/csd/`.
+
+```bash
+./run-csd.sh
+```
+
+**Key Parameters:**
+```bash
+fdm_size=64            # Functional data memory size (MB), required
+nr_cu=4                # Number of compute units
+nr_thread=4            # Number of functional simulation threads
+time_slice=200000      # Scheduler time slice (ns)
+context_switch_time=200 # Context switch time (ns)
+csf_runtime_scale=3    # Runtime scaling factor
+```
+
+**Current Scope:**
+- Normal NVMe read/write through the device-side BBSSD FTL path in CSD mode
+- Vendor commands for AFDM allocation, read/write, NVM-to-AFDM copy
+- Phantom and shared-library CSF load/execute path using the original CEMU
+  lifecycle, `path\0symbol\0` program descriptor format, and program execute
+  fields (`pind`, `numr`, `dlen`, `cparam1`, `cparam2`, `group`, `runtime`)
+- CEMU-style admin commands for CSF load/unload and activate/deactivate
+- Optional uBPF CSF support via `./femu-compile.sh --enable-csd-ubpf`
+  or `./femu-compile.sh --enable-csd-ubpf=/path/to/ubpf-cemu`
+- Group/QoS command metadata
+- Guest-side passthrough tests in `tests/femu-csd/`
+
+The initial CSD path does not require a CEMU-specific Linux kernel, FDMFS, or a
+fixed VM image. Advanced CEMU features such as VM freezing, virtual clock
+changes, and FDMFS are intentionally kept out of the default path while the base
+mode is upstreamed.
+
 ---
 
 ## Configuration
@@ -451,6 +488,9 @@ hw/femu/                    # Main FEMU implementation
 │   └── zftl.c              # Zone-based FTL
 ├── nossd/                  # NoSSD mode
 │   └── nop.c               # Minimal processing
+├── csd/                    # Computational Storage mode
+│   ├── csd.c               # CSD command handling
+│   └── csd.h               # CSD private command definitions
 ├── timing-model/           # Performance modeling
 ├── backend/                # Storage backends
 └── lib/                    # Utility libraries

femu-scripts/femu-compile.sh

@@ -1,10 +1,28 @@
 #!/bin/bash
 
 NRCPUS="$(cat /proc/cpuinfo | grep "vendor_id" | wc -l)"
+FEMU_CONFIGURE_OPTS=""
+
+for arg in "$@"; do
+    case "$arg" in
+        --enable-csd-ubpf)
+            FEMU_CONFIGURE_OPTS="${FEMU_CONFIGURE_OPTS} --enable-femu-csd-ubpf"
+            ;;
+        --enable-csd-ubpf=*)
+            UBPF_PATH="${arg#*=}"
+            FEMU_CONFIGURE_OPTS="${FEMU_CONFIGURE_OPTS} --enable-femu-csd-ubpf -Dfemu_csd_ubpf_path=${UBPF_PATH}"
+            ;;
+        *)
+            echo "Unknown option: $arg"
+            echo "Usage: $0 [--enable-csd-ubpf[=/path/to/ubpf-cemu]]"
+            exit 1
+            ;;
+    esac
+done
 
 make clean
 # --disable-werror --extra-cflags=-w --disable-git-update
-../configure --enable-kvm --target-list=x86_64-softmmu --enable-slirp
+../configure --enable-kvm --target-list=x86_64-softmmu --enable-slirp ${FEMU_CONFIGURE_OPTS}
 make -j $NRCPUS
 
 echo ""

femu-scripts/femu-copy-scripts.sh

@@ -4,7 +4,7 @@
 
 FSD="../femu-scripts"
 
-CPL=(pkgdep.sh femu-compile.sh run-whitebox.sh run-blackbox.sh run-blackbox-fdp.sh run-nossd.sh run-zns.sh pin.sh ftk)
+CPL=(pkgdep.sh femu-compile.sh run-whitebox.sh run-blackbox.sh run-blackbox-fdp.sh run-nossd.sh run-zns.sh run-csd.sh pin.sh ftk)
 
 echo ""
 echo "==> Copying following FEMU script to current directory:"
@@ -18,4 +18,3 @@ do
 done
 echo "Done!"
 echo ""
-

femu-scripts/run-csd.sh

@@ -0,0 +1,88 @@
+#!/bin/bash
+# Run FEMU as a Computational Storage Drive (CSD)
+
+# Image directory
+IMGDIR=$HOME/images
+# Virtual machine disk image
+OSIMGF=$IMGDIR/u20s.qcow2
+
+# Configurable SSD Controller layout parameters (must be power of 2)
+secsz=512 # sector size in bytes
+secs_per_pg=8 # number of sectors in a flash page
+pgs_per_blk=256 # number of pages per flash block
+blks_per_pl=256 # number of blocks per plane
+pls_per_lun=1 # keep it at one, no multiplanes support
+luns_per_ch=8 # number of chips per channel
+nchs=8 # number of channels
+ssd_size=4096 # in megabytes
+
+# Latency in nanoseconds
+pg_rd_lat=40000 # page read latency
+pg_wr_lat=200000 # page write latency
+blk_er_lat=2000000 # block erase latency
+ch_xfer_lat=0 # channel transfer time, ignored for now
+
+# GC Threshold (1-100)
+gc_thres_pcent=75
+gc_thres_pcent_high=95
+
+# FEMU CSD parameters
+fdm_size=64
+nr_cu=4
+nr_thread=4
+time_slice=200000
+context_switch_time=200
+csf_runtime_scale=3
+
+#-----------------------------------------------------------------------
+
+# Compose the entire FEMU CSD command line options
+FEMU_OPTIONS="-device femu"
+FEMU_OPTIONS=${FEMU_OPTIONS}",devsz_mb=${ssd_size}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",namespaces=1"
+FEMU_OPTIONS=${FEMU_OPTIONS}",femu_mode=4"
+FEMU_OPTIONS=${FEMU_OPTIONS}",secsz=${secsz}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",secs_per_pg=${secs_per_pg}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",pgs_per_blk=${pgs_per_blk}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",blks_per_pl=${blks_per_pl}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",pls_per_lun=${pls_per_lun}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",luns_per_ch=${luns_per_ch}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",nchs=${nchs}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",pg_rd_lat=${pg_rd_lat}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",pg_wr_lat=${pg_wr_lat}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",blk_er_lat=${blk_er_lat}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",ch_xfer_lat=${ch_xfer_lat}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",gc_thres_pcent=${gc_thres_pcent}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",gc_thres_pcent_high=${gc_thres_pcent_high}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",fdm_size=${fdm_size}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",nr_cu=${nr_cu}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",nr_thread=${nr_thread}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",time_slice=${time_slice}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",context_switch_time=${context_switch_time}"
+FEMU_OPTIONS=${FEMU_OPTIONS}",csf_runtime_scale=${csf_runtime_scale}"
+
+echo ${FEMU_OPTIONS}
+
+if [[ ! -e "$OSIMGF" ]]; then
+	echo ""
+	echo "VM disk image couldn't be found ..."
+	echo "Please prepare a usable VM image and place it as $OSIMGF"
+	echo "Once VM disk image is ready, please rerun this script again"
+	echo ""
+	exit
+fi
+
+sudo ./qemu-system-x86_64 \
+    -name "FEMU-CSD-VM" \
+    -enable-kvm \
+    -cpu host \
+    -smp 4 \
+    -m 4G \
+    -device virtio-scsi-pci,id=scsi0 \
+    -device scsi-hd,drive=hd0 \
+    -drive file=$OSIMGF,if=none,aio=native,cache=none,format=qcow2,id=hd0 \
+    ${FEMU_OPTIONS} \
+    -net user,hostfwd=tcp::8080-:22 \
+    -net nic,model=virtio \
+    -nographic \
+    -qmp unix:./qmp-sock,server,nowait 2>&1 | tee log

hw/femu/backend/dram.c

@@ -57,7 +57,8 @@ int backend_rw(SsdDramBackend *b, QEMUSGList *qsg, uint64_t *lbal, bool is_write
             mb_oft = lbal[sg_cur_index];
         } else if (b->femu_mode == FEMU_BBSSD_MODE ||
                    b->femu_mode == FEMU_NOSSD_MODE ||
-                   b->femu_mode == FEMU_ZNSSD_MODE) {
+                   b->femu_mode == FEMU_ZNSSD_MODE ||
+                   b->femu_mode == FEMU_CSD_MODE) {
             mb_oft += cur_len;
         } else {
             assert(0);