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[Qemu-devel] [PULL 02/29] scsi-disk: support reporting of rotation rate
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PULL 02/29] scsi-disk: support reporting of rotation rate |
Date: |
Wed, 18 Oct 2017 18:11:54 +0200 |
From: "Daniel P. Berrange" <address@hidden>
The Linux kernel will query the SCSI "Block device characteristics"
VPD to determine the rotations per minute of the disk. If this has
the value 1, it is taken to be an SSD and so Linux sets the
'rotational' flag to 0 for the I/O queue and will stop using that
disk as a source of random entropy. Other operating systems may
also take into account rotation rate when setting up default
behaviour.
Mgmt apps should be able to set the rotation rate for virtualized
block devices, based on characteristics of the host storage in use,
so that the guest OS gets sensible behaviour out of the box. This
patch thus adds a 'rotation-rate' parameter for 'scsi-hd' and
'scsi-block' device types. For the latter, this parameter will be
ignored unless the host device has TYPE_DISK.
Signed-off-by: Daniel P. Berrange <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
hw/scsi/scsi-disk.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index 6e841fb..a518080 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -104,6 +104,14 @@ typedef struct SCSIDiskState
char *product;
bool tray_open;
bool tray_locked;
+ /*
+ * 0x0000 - rotation rate not reported
+ * 0x0001 - non-rotating medium (SSD)
+ * 0x0002-0x0400 - reserved
+ * 0x0401-0xffe - rotations per minute
+ * 0xffff - reserved
+ */
+ uint16_t rotation_rate;
} SCSIDiskState;
static bool scsi_handle_rw_error(SCSIDiskReq *r, int error, bool acct_failed);
@@ -605,6 +613,7 @@ static int scsi_disk_emulate_inquiry(SCSIRequest *req,
uint8_t *outbuf)
outbuf[buflen++] = 0x83; // device identification
if (s->qdev.type == TYPE_DISK) {
outbuf[buflen++] = 0xb0; // block limits
+ outbuf[buflen++] = 0xb1; /* block device characteristics */
outbuf[buflen++] = 0xb2; // thin provisioning
}
break;
@@ -747,6 +756,15 @@ static int scsi_disk_emulate_inquiry(SCSIRequest *req,
uint8_t *outbuf)
outbuf[43] = max_io_sectors & 0xff;
break;
}
+ case 0xb1: /* block device characteristics */
+ {
+ buflen = 8;
+ outbuf[4] = (s->rotation_rate >> 8) & 0xff;
+ outbuf[5] = s->rotation_rate & 0xff;
+ outbuf[6] = 0;
+ outbuf[7] = 0;
+ break;
+ }
case 0xb2: /* thin provisioning */
{
buflen = 8;
@@ -2911,6 +2929,7 @@ static Property scsi_hd_properties[] = {
DEFAULT_MAX_UNMAP_SIZE),
DEFINE_PROP_UINT64("max_io_size", SCSIDiskState, max_io_size,
DEFAULT_MAX_IO_SIZE),
+ DEFINE_PROP_UINT16("rotation_rate", SCSIDiskState, rotation_rate, 0),
DEFINE_BLOCK_CHS_PROPERTIES(SCSIDiskState, qdev.conf),
DEFINE_PROP_END_OF_LIST(),
};
@@ -2982,6 +3001,7 @@ static const TypeInfo scsi_cd_info = {
static Property scsi_block_properties[] = {
DEFINE_BLOCK_ERROR_PROPERTIES(SCSIDiskState, qdev.conf), \
DEFINE_PROP_DRIVE("drive", SCSIDiskState, qdev.conf.blk),
+ DEFINE_PROP_UINT16("rotation_rate", SCSIDiskState, rotation_rate, 0),
DEFINE_PROP_END_OF_LIST(),
};
--
1.8.3.1
- [Qemu-devel] [PULL 00/29] Misc patches for 2017-10-18, Paolo Bonzini, 2017/10/18
- [Qemu-devel] [PULL 02/29] scsi-disk: support reporting of rotation rate,
Paolo Bonzini <=
- [Qemu-devel] [PULL 04/29] char: don't skip client cleanup if 'connected' flag is unset, Paolo Bonzini, 2017/10/18
- [Qemu-devel] [PULL 01/29] checkpatch: refine mode selection, Paolo Bonzini, 2017/10/18
- [Qemu-devel] [PULL 07/29] memory: fix off-by-one error in memory_region_notify_one(), Paolo Bonzini, 2017/10/18
- [Qemu-devel] [PULL 05/29] exec: add page_mask for flatview_do_translate, Paolo Bonzini, 2017/10/18
- [Qemu-devel] [PULL 03/29] ide: support reporting of rotation rate, Paolo Bonzini, 2017/10/18
- [Qemu-devel] [PULL 06/29] exec: simplify address_space_get_iotlb_entry, Paolo Bonzini, 2017/10/18
- [Qemu-devel] [PULL 08/29] pc: make sure that plugged CPUs are of the same type, Paolo Bonzini, 2017/10/18
- [Qemu-devel] [PULL 09/29] disas: Always initialize read_memory_inner_func properly, Paolo Bonzini, 2017/10/18
- [Qemu-devel] [PULL 10/29] build: remove CONFIG_LIBDECNUMBER, Paolo Bonzini, 2017/10/18
- [Qemu-devel] [PULL 13/29] tco: add trace events, Paolo Bonzini, 2017/10/18