The following changes since commit b0ca999a43a22b38158a222233d3f5881648bb4f:

Update version for v4.2.0 release (2019-12-12 16:45:57 +0000)

are available in the Git repository at:

https://github.com/stefanha/qemu.git tags/block-pull-request

for you to fetch changes up to 86d2a49b41832355ab50cf60cec0cd50680fc0e5:

iothread: document -object iothread on man page (2019-12-13 11:24:07 +0000)

Pull request

Evgeny Yakovlev (1):

virtio-blk: advertise F_WCE (F_FLUSH) if F_CONFIG_WCE is advertised

Stefan Hajnoczi (1):

iothread: document -object iothread on man page

hw/arm/virt.c | 1 +

hw/block/virtio-blk.c | 6 +++++-

hw/core/machine.c | 5 +++++

hw/i386/pc_piix.c | 1 +

hw/i386/pc_q35.c | 1 +

hw/ppc/spapr.c | 2 +-

hw/s390x/s390-virtio-ccw.c | 1 +

include/hw/boards.h | 3 +++

include/hw/virtio/virtio-blk.h | 1 +

qemu-options.hx | 38 ++++++++++++++++++++++++++++++++++

10 files changed, 57 insertions(+), 2 deletions(-)

2.23.0

From: Evgeny Yakovlev <wrfsh@yandex-team.ru>

Virtio spec 1.1 (and earlier), 5.2.5.2 Driver Requirements: Device

Initialization:

"Devices SHOULD always offer VIRTIO_BLK_F_FLUSH, and MUST offer it if

they offer VIRTIO_BLK_F_CONFIG_WCE"

Currently F_CONFIG_WCE and F_WCE are not connected to each other.

Qemu will advertise F_CONFIG_WCE if config-wce argument is

set for virtio-blk device. And F_WCE is advertised only if

underlying block backend actually has it's caching enabled.

Fix this by advertising F_WCE if F_CONFIG_WCE is also advertised.

To preserve backwards compatibility with newer machine types make this

behaviour governed by "x-enable-wce-if-config-wce" virtio-blk-device

property and introduce hw_compat_4_2 with new property being off by

default for all machine types <= 4.2 (but don't introduce 4.3

machine type itself yet).

Signed-off-by: Evgeny Yakovlev <wrfsh@yandex-team.ru>

Message-Id: <1572978137-189218-1-git-send-email-wrfsh@yandex-team.ru>

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

hw/arm/virt.c | 1 +

hw/block/virtio-blk.c | 6 +++++-

hw/core/machine.c | 5 +++++

hw/i386/pc_piix.c | 1 +

hw/i386/pc_q35.c | 1 +

hw/ppc/spapr.c | 2 +-

hw/s390x/s390-virtio-ccw.c | 1 +

include/hw/boards.h | 3 +++

include/hw/virtio/virtio-blk.h | 1 +

9 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c

--- a/hw/arm/virt.c

+++ b/hw/arm/virt.c

@@ -XXX,XX +XXX,XX @@ type_init(machvirt_machine_init);

static void virt_machine_4_2_options(MachineClass *mc)

{

+ compat_props_add(mc->compat_props, hw_compat_4_2, hw_compat_4_2_len);

}

DEFINE_VIRT_MACHINE_AS_LATEST(4, 2)

diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c

index XXXXXXX..XXXXXXX 100644

--- a/hw/block/virtio-blk.c

+++ b/hw/block/virtio-blk.c

@@ -XXX,XX +XXX,XX @@ static uint64_t virtio_blk_get_features(VirtIODevice *vdev, uint64_t features,

virtio_add_feature(&features, VIRTIO_BLK_F_SCSI);

}

- if (blk_enable_write_cache(s->blk)) {

+ if (blk_enable_write_cache(s->blk) ||

+ (s->conf.x_enable_wce_if_config_wce &&

+ virtio_has_feature(features, VIRTIO_BLK_F_CONFIG_WCE))) {

virtio_add_feature(&features, VIRTIO_BLK_F_WCE);

}

if (blk_is_read_only(s->blk)) {

@@ -XXX,XX +XXX,XX @@ static Property virtio_blk_properties[] = {

conf.max_discard_sectors, BDRV_REQUEST_MAX_SECTORS),

DEFINE_PROP_UINT32("max-write-zeroes-sectors", VirtIOBlock,

conf.max_write_zeroes_sectors, BDRV_REQUEST_MAX_SECTORS),

+ DEFINE_PROP_BOOL("x-enable-wce-if-config-wce", VirtIOBlock,

+ conf.x_enable_wce_if_config_wce, true),

DEFINE_PROP_END_OF_LIST(),

};

diff --git a/hw/core/machine.c b/hw/core/machine.c

index XXXXXXX..XXXXXXX 100644

--- a/hw/core/machine.c

+++ b/hw/core/machine.c

#include "hw/pci/pci.h"

#include "hw/mem/nvdimm.h"

+GlobalProperty hw_compat_4_2[] = {

+ { "virtio-blk-device", "x-enable-wce-if-config-wce", "off" },

+};

+const size_t hw_compat_4_2_len = G_N_ELEMENTS(hw_compat_4_2);

+

GlobalProperty hw_compat_4_1[] = {

{ "virtio-pci", "x-pcie-flr-init", "off" },

};

diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c

index XXXXXXX..XXXXXXX 100644

--- a/hw/i386/pc_piix.c

+++ b/hw/i386/pc_piix.c

@@ -XXX,XX +XXX,XX @@ static void pc_i440fx_4_2_machine_options(MachineClass *m)

m->alias = "pc";

m->is_default = 1;

pcmc->default_cpu_version = 1;

+ compat_props_add(m->compat_props, hw_compat_4_2, hw_compat_4_2_len);

}

DEFINE_I440FX_MACHINE(v4_2, "pc-i440fx-4.2", NULL,

diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c

index XXXXXXX..XXXXXXX 100644

--- a/hw/i386/pc_q35.c

+++ b/hw/i386/pc_q35.c

@@ -XXX,XX +XXX,XX @@ static void pc_q35_4_2_machine_options(MachineClass *m)

pc_q35_machine_options(m);

m->alias = "q35";

pcmc->default_cpu_version = 1;

+ compat_props_add(m->compat_props, hw_compat_4_2, hw_compat_4_2_len);

}

DEFINE_Q35_MACHINE(v4_2, "pc-q35-4.2", NULL,

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c

index XXXXXXX..XXXXXXX 100644

--- a/hw/ppc/spapr.c

+++ b/hw/ppc/spapr.c

@@ -XXX,XX +XXX,XX @@ static const TypeInfo spapr_machine_info = {

*/

static void spapr_machine_4_2_class_options(MachineClass *mc)

{

- /* Defaults for the latest behaviour inherited from the base class */

+ compat_props_add(mc->compat_props, hw_compat_4_2, hw_compat_4_2_len);

}

DEFINE_SPAPR_MACHINE(4_2, "4.2", true);

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c

index XXXXXXX..XXXXXXX 100644

--- a/hw/s390x/s390-virtio-ccw.c

+++ b/hw/s390x/s390-virtio-ccw.c

@@ -XXX,XX +XXX,XX @@ static void ccw_machine_4_2_instance_options(MachineState *machine)

static void ccw_machine_4_2_class_options(MachineClass *mc)

{

+ compat_props_add(mc->compat_props, hw_compat_4_2, hw_compat_4_2_len);

}

DEFINE_CCW_MACHINE(4_2, "4.2", true);

diff --git a/include/hw/boards.h b/include/hw/boards.h

index XXXXXXX..XXXXXXX 100644

--- a/include/hw/boards.h

+++ b/include/hw/boards.h

@@ -XXX,XX +XXX,XX @@ struct MachineState {

} \

type_init(machine_initfn##_register_types)

+extern GlobalProperty hw_compat_4_2[];

+extern const size_t hw_compat_4_2_len;

+

extern GlobalProperty hw_compat_4_1[];

extern const size_t hw_compat_4_1_len;

diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h

index XXXXXXX..XXXXXXX 100644

--- a/include/hw/virtio/virtio-blk.h

+++ b/include/hw/virtio/virtio-blk.h

@@ -XXX,XX +XXX,XX @@ struct VirtIOBlkConf

uint16_t queue_size;

uint32_t max_discard_sectors;

uint32_t max_write_zeroes_sectors;

+ bool x_enable_wce_if_config_wce;

};

struct VirtIOBlockDataPlane;

2.23.0

Add -object iothread documentation to the man page, including references

to the query-iothread QMP command and qom-set syntax for adjusting

adaptive polling parameters at run-time.

Reported-by: Zhenyu Ye <yezhenyu2@huawei.com>

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Message-id: 20191025122236.29815-1-stefanha@redhat.com

Message-Id: <20191025122236.29815-1-stefanha@redhat.com>

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

---

qemu-options.hx | 38 ++++++++++++++++++++++++++++++++++++++

1 file changed, 38 insertions(+)

diff --git a/qemu-options.hx b/qemu-options.hx

--- a/qemu-options.hx

+++ b/qemu-options.hx

@@ -XXX,XX +XXX,XX @@ access

CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB

@end example

+@item -object iothread,id=@var{id},poll-max-ns=@var{poll-max-ns},poll-grow=@var{poll-grow},poll-shrink=@var{poll-shrink}

+

+Creates a dedicated event loop thread that devices can be assigned to. This is

+known as an IOThread. By default device emulation happens in vCPU threads or

+the main event loop thread. This can become a scalability bottleneck.

+IOThreads allow device emulation and I/O to run on other host CPUs.

+

+The @option{id} parameter is a unique ID that will be used to reference this

+IOThread from @option{-device ...,iothread=@var{id}}. Multiple devices can be

+assigned to an IOThread. Note that not all devices support an

+@option{iothread} parameter.

+

+The @code{query-iothreads} QMP command lists IOThreads and reports their thread

+IDs so that the user can configure host CPU pinning/affinity.

+

+IOThreads use an adaptive polling algorithm to reduce event loop latency.

+Instead of entering a blocking system call to monitor file descriptors and then

+pay the cost of being woken up when an event occurs, the polling algorithm

+spins waiting for events for a short time. The algorithm's default parameters

+are suitable for many cases but can be adjusted based on knowledge of the

+workload and/or host device latency.

+

+The @option{poll-max-ns} parameter is the maximum number of nanoseconds to busy

+wait for events. Polling can be disabled by setting this value to 0.

+

+The @option{poll-grow} parameter is the multiplier used to increase the polling

+time when the algorithm detects it is missing events due to not polling long

+enough.

+

+The @option{poll-shrink} parameter is the divisor used to decrease the polling

+time when the algorithm detects it is spending too long polling without

+encountering events.

+

+The polling parameters can be modified at run-time using the @code{qom-set} command (where @code{iothread1} is the IOThread's @code{id}):

+

+@example

+(qemu) qom-set /objects/iothread1 poll-max-ns 100000

+@end example

@end table

2.23.0