[Qemu-devel] [PATCH 6/7] ide: add TRIM support

[Christoph Hellwig <hch@lst.de>]

Add support for the data set management command, and the TRIM sub function
in it.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: qemu/hw/ide/core.c
===================================================================
--- qemu.orig/hw/ide/core.c	2010-12-10 11:35:30.471253949 +0100
+++ qemu/hw/ide/core.c	2010-12-10 11:35:33.430253739 +0100
@@ -146,6 +146,9 @@ static void ide_identify(IDEState *s)
     put_le16(p + 66, 120);
     put_le16(p + 67, 120);
     put_le16(p + 68, 120);
+    if (dev && dev->conf.discard_granularity) {
+        put_le16(p + 69, (1 << 14)); /* determinate TRIM behavior */
+    }
     put_le16(p + 80, 0xf0); /* ata3 -> ata6 supported */
     put_le16(p + 81, 0x16); /* conforms to ata5 */
     /* 14=NOP supported, 5=WCACHE supported, 0=SMART supported */
@@ -172,6 +175,9 @@ static void ide_identify(IDEState *s)
     dev = s->unit ? s->bus->slave : s->bus->master;
     if (dev && dev->conf.physical_block_size)
         put_le16(p + 106, 0x6000 | get_physical_block_exp(&dev->conf));
+    if (dev && dev->conf.discard_granularity) {
+        put_le16(p + 169, 1); /* TRIM support */
+    }
 
     memcpy(s->identify_data, p, sizeof(s->identify_data));
     s->identify_set = 1;
@@ -1746,6 +1752,72 @@ static void ide_clear_hob(IDEBus *bus)
     bus->ifs[1].select &= ~(1 << 7);
 }
 
+typedef struct TrimAIOCB {
+    BlockDriverAIOCB common;
+    QEMUBH *bh;
+    int ret;
+} TrimAIOCB;
+
+static void trim_aio_cancel(BlockDriverAIOCB *acb)
+{
+    TrimAIOCB *iocb = container_of(acb, TrimAIOCB, common);
+
+    qemu_bh_delete(iocb->bh);
+    iocb->bh = NULL;
+    qemu_aio_release(iocb);
+}
+
+static AIOPool trim_aio_pool = {
+    .aiocb_size         = sizeof(TrimAIOCB),
+    .cancel             = trim_aio_cancel,
+};
+
+static void ide_trim_bh_cb(void *opaque)
+{
+    TrimAIOCB *iocb = opaque;
+
+    iocb->common.cb(iocb->common.opaque, iocb->ret);
+
+    qemu_bh_delete(iocb->bh);
+    iocb->bh = NULL;
+
+    qemu_aio_release(iocb);
+}
+
+static BlockDriverAIOCB *ide_issue_trim(BlockDriverState *bs,
+        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
+        BlockDriverCompletionFunc *cb, void *opaque)
+{
+    TrimAIOCB *iocb;
+    int i, j, ret;
+
+    iocb = qemu_aio_get(&trim_aio_pool, bs, cb, opaque);
+    iocb->bh = qemu_bh_new(ide_trim_bh_cb, iocb);
+    iocb->ret = 0;
+
+    for (j = 0; j < qiov->niov; j++) {
+        uint64_t *buffer = qiov->iov[j].iov_base;
+
+        for (i = 0; i < qiov->iov[j].iov_len / 8; i++) {
+            /* 6-byte LBA + 2-byte range per entry */
+            uint64_t entry = le64_to_cpu(buffer[i]);
+            uint64_t sector = entry & 0x0000ffffffffffffULL;
+            uint16_t count = entry >> 48;
+
+            if (count == 0)
+                break;
+
+            ret = bdrv_discard(bs, sector * 512, count * 512);
+            if (!iocb->ret)
+                iocb->ret = ret;
+        }
+    }
+
+    qemu_bh_schedule(iocb->bh);
+
+    return &iocb->common;
+}
+
 void ide_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 {
     IDEBus *bus = opaque;
@@ -1825,6 +1897,17 @@ void ide_ioport_write(void *opaque, uint
             break;
 
         switch(val) {
+        case WIN_DSM:
+            switch (s->feature) {
+            case DSM_TRIM:
+                if (!s->bs)
+                   goto abort_cmd;
+                ide_sector_dma(s, ide_issue_trim, 0);
+                break;
+            default:
+                goto abort_cmd;
+            }
+            break;
         case WIN_IDENTIFY:
             if (s->bs && s->drive_kind != IDE_CD) {
                 if (s->drive_kind != IDE_CFATA)
Index: qemu/hw/ide/internal.h
===================================================================
--- qemu.orig/hw/ide/internal.h	2010-12-10 11:33:41.444006150 +0100
+++ qemu/hw/ide/internal.h	2010-12-10 11:35:33.446003914 +0100
@@ -60,7 +60,11 @@ typedef struct BMDMAState BMDMAState;
  */
 #define CFA_REQ_EXT_ERROR_CODE		0x03 /* CFA Request Extended Error Code */
 /*
- *	0x04->0x07 Reserved
+ *      0x04->0x05 Reserved
+ */
+#define WIN_DSM                         0x06
+/*
+ *      0x07 Reserved
  */
 #define WIN_SRST			0x08 /* ATAPI soft reset command */
 #define WIN_DEVICE_RESET		0x08
@@ -188,6 +192,9 @@ typedef struct BMDMAState BMDMAState;
 
 #define IDE_DMA_BUF_SECTORS 256
 
+/* feature values for Data Set Management */
+#define DSM_TRIM                        0x01
+
 #if (IDE_DMA_BUF_SECTORS < MAX_MULT_SECTORS)
 #error "IDE_DMA_BUF_SECTORS must be bigger or equal to MAX_MULT_SECTORS"
 #endif
Index: qemu/hw/ide/qdev.c
===================================================================
--- qemu.orig/hw/ide/qdev.c	2010-12-10 11:24:19.324253880 +0100
+++ qemu/hw/ide/qdev.c	2010-12-10 11:35:33.450257860 +0100
@@ -110,6 +110,11 @@ static int ide_drive_initfn(IDEDevice *d
     const char *serial;
     DriveInfo *dinfo;
 
+    if (dev->conf.discard_granularity && dev->conf.discard_granularity != 512) {
+        error_report("discard_granularity must be 512 for ide");
+        return -1;
+    }
+
     serial = dev->serial;
     if (!serial) {
         /* try to fall back to value set with legacy -drive serial=... */