From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41582) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dzi2O-0000Gl-6n for qemu-devel@nongnu.org; Wed, 04 Oct 2017 07:40:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dzi2N-0005iB-3i for qemu-devel@nongnu.org; Wed, 04 Oct 2017 07:40:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33610) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dzi2M-0005fk-R5 for qemu-devel@nongnu.org; Wed, 04 Oct 2017 07:40:27 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E0AB5820F8 for ; Wed, 4 Oct 2017 11:40:25 +0000 (UTC) From: "Daniel P. Berrange" Date: Wed, 4 Oct 2017 12:40:07 +0100 Message-Id: <20171004114008.14849-2-berrange@redhat.com> In-Reply-To: <20171004114008.14849-1-berrange@redhat.com> References: <20171004114008.14849-1-berrange@redhat.com> Subject: [Qemu-devel] [PATCH v1 1/2] scsi-disk: support reporting of rotation rate List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Paolo Bonzini , John Snow , "Daniel P. Berrange" 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 --- 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 6e841fb5ff..a518080e7d 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(), }; -- 2.13.5