From 23c1feb875805a4c324c51c3916b249da0edbe02 Mon Sep 17 00:00:00 2001
From: "Daniel P. Berrange" <berrange@redhat.com>
Date: Wed, 29 Nov 2017 14:26:04 +0100
Subject: [PATCH 18/21] scsi-disk: support reporting of rotation rate
RH-Author: Daniel P. Berrange <berrange@redhat.com>
Message-id: <20171129142606.15965-2-berrange@redhat.com>
Patchwork-id: 77961
O-Subject: [PATCH RHV-7.5 qemu-kvm-rhev 1/3] scsi-disk: support reporting of rotation rate
Bugzilla: 1498042
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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 <berrange@redhat.com>
Message-Id: <20171004114008.14849-2-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 070f80095ad5b1143b50d2faffd2b1a84292e00d)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
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 5f1e5e8..21d6b4e 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 int scsi_handle_rw_error(SCSIDiskReq *r, int error, bool acct_failed);
@@ -597,6 +605,7 @@ 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;
@@ -739,6 +748,15 @@ 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;
@@ -2903,6 +2921,7 @@ 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(),
};
@@ -2973,6 +2992,7 @@ static const TypeInfo scsi_cd_info = {
#ifdef __linux__
static Property scsi_block_properties[] = {
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