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From f4030862f7ac7e6217415e3ca6be6a4151fa8208 Mon Sep 17 00:00:00 2001
From: John Snow <jsnow@redhat.com>
Date: Thu, 2 Aug 2018 15:53:35 +0200
Subject: [PATCH 2/4] ide: support reporting of rotation rate

RH-Author: John Snow <jsnow@redhat.com>
Message-id: <20180802155336.10347-3-jsnow@redhat.com>
Patchwork-id: 81614
O-Subject: [RHEL-7.6 qemu-kvm PATCH 2/3] ide: support reporting of rotation rate
Bugzilla: 1583807
RH-Acked-by: Daniel P. Berrange <berrange@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>

From: "Daniel P. Berrange" <berrange@redhat.com>

The Linux kernel will query the ATA IDENTITY DEVICE data, word 217
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 'ide-hd' device
types.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <20171004114008.14849-3-berrange@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 3b19f4506901ecce25ff36cf62353a2b4bfe4f2b)
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/ide/core.c     | 1 +
 hw/ide/internal.h | 8 ++++++++
 hw/ide/qdev.c     | 1 +
 3 files changed, 10 insertions(+)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index 5c33735..aea2ff9 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -179,6 +179,7 @@ static void ide_identify(IDEState *s)
     if (dev && dev->conf.discard_granularity) {
         put_le16(p + 169, 1); /* TRIM support */
     }
+    put_le16(p + 217, dev->rotation_rate); /* Nominal media rotation rate */
 
     memcpy(s->identify_data, p, sizeof(s->identify_data));
     s->identify_set = 1;
diff --git a/hw/ide/internal.h b/hw/ide/internal.h
index f8fb564..1062f85 100644
--- a/hw/ide/internal.h
+++ b/hw/ide/internal.h
@@ -484,6 +484,14 @@ struct IDEDevice {
     char *serial;
     char *model;
     uint64_t wwn;
+    /*
+     * 0x0000        - rotation rate not reported
+     * 0x0001        - non-rotating medium (SSD)
+     * 0x0002-0x0400 - reserved
+     * 0x0401-0xffe  - rotations per minute
+     * 0xffff        - reserved
+     */
+    uint16_t rotation_rate;
 };
 
 #define BM_STATUS_DMAING 0x01
diff --git a/hw/ide/qdev.c b/hw/ide/qdev.c
index 44f36c3..4ba2c63 100644
--- a/hw/ide/qdev.c
+++ b/hw/ide/qdev.c
@@ -219,6 +219,7 @@ static Property ide_hd_properties[] = {
     DEFINE_BLOCK_CHS_PROPERTIES(IDEDrive, dev.conf),
     DEFINE_PROP_BIOS_CHS_TRANS("bios-chs-trans",
                 IDEDrive, dev.chs_trans, BIOS_ATA_TRANSLATION_AUTO),
+    DEFINE_PROP_UINT16("rotation_rate", IDEDrive, dev.rotation_rate, 0),
     DEFINE_PROP_END_OF_LIST(),
 };
 
-- 
1.8.3.1