[PATCH v6 0/7] virtio-pci: enable blk and scsi multi-queue by default

[PATCH v6 0/7] virtio-pci: enable blk and scsi multi-queue by default

[Stefan Hajnoczi]

v6:
 * Rebased onto QEMU 5.1 and added the now-necessary machine compat opts.

v4:
 * Sorry for the long delay. I considered replacing this series with a simpler
   approach. Real hardware ships with a fixed number of queues (e.g. 128). The
   equivalent can be done in QEMU too. That way we don't need to magically si=
ze
   num_queues. In the end I decided against this approach because the Linux
   virtio_blk.ko and virtio_scsi.ko guest drivers unconditionally initialized
   all available queues until recently (it was written with
   num_queues=3Dnum_vcpus in mind). It doesn't make sense for a 1 CPU guest to
   bring up 128 virtqueues (waste of resources and possibly weird performance
   effects with blk-mq).
 * Honor maximum number of MSI-X vectors and virtqueues [Daniel Berrange]
 * Update commit descriptions to mention maximum MSI-X vector and virtqueue
   caps [Raphael]
v3:
 * Introduce virtio_pci_optimal_num_queues() helper to enforce VIRTIO_QUEUE_M=
AX
   in one place
 * Use VIRTIO_SCSI_VQ_NUM_FIXED constant in all cases [Cornelia]
 * Update hw/core/machine.c compat properties for QEMU 5.0 [Michael]
v3:
 * Add new performance results that demonstrate the scalability
 * Mention that this is PCI-specific [Cornelia]
v2:
 * Let the virtio-DEVICE-pci device select num-queues because the optimal
   multi-queue configuration may differ between virtio-pci, virtio-mmio, and
   virtio-ccw [Cornelia]

Enabling multi-queue on virtio-pci storage devices improves performance on SMP
guests because the completion interrupt is handled on the vCPU that submitted
the I/O request.  This avoids IPIs inside the guest.

Note that performance is unchanged in these cases:
1. Uniprocessor guests.  They don't have IPIs.
2. Application threads might be scheduled on the sole vCPU that handles
   completion interrupts purely by chance.  (This is one reason why benchmark
   results can vary noticably between runs.)
3. Users may bind the application to the vCPU that handles completion
   interrupts.

Set the number of queues to the number of vCPUs by default on virtio-blk and
virtio-scsi PCI devices.  Older machine types continue to default to 1 queue
for live migration compatibility.

Random read performance:
      IOPS
q=3D1    78k
q=3D32  104k  +33%

Boot time:
      Duration
q=3D1        51s
q=3D32     1m41s  +98%

Guest configuration: 32 vCPUs, 101 virtio-blk-pci disks

Previously measured results on a 4 vCPU guest were also positive but showed a
smaller 1-4% performance improvement.  They are no longer valid because
significant event loop optimizations have been merged.

Peter Maydell (1):
  Open 5.2 development tree

Stefan Hajnoczi (6):
  hw: add 5.2 machine types and 5.1 compat options
  virtio-pci: add virtio_pci_optimal_num_queues() helper
  virtio-scsi: introduce a constant for fixed virtqueues
  virtio-scsi-pci: default num_queues to -smp N
  virtio-blk-pci: default num_queues to -smp N
  vhost-user-blk-pci: default num_queues to -smp N

 hw/virtio/virtio-pci.h             |  9 +++++++++
 include/hw/boards.h                |  3 +++
 include/hw/i386/pc.h               |  3 +++
 include/hw/virtio/vhost-user-blk.h |  2 ++
 include/hw/virtio/virtio-blk.h     |  2 ++
 include/hw/virtio/virtio-scsi.h    |  5 +++++
 hw/arm/virt.c                      |  9 ++++++++-
 hw/block/vhost-user-blk.c          |  6 +++++-
 hw/block/virtio-blk.c              |  6 +++++-
 hw/core/machine.c                  |  9 +++++++++
 hw/i386/pc.c                       |  4 ++++
 hw/i386/pc_piix.c                  | 14 ++++++++++++-
 hw/i386/pc_q35.c                   | 13 +++++++++++-
 hw/ppc/spapr.c                     | 15 ++++++++++++--
 hw/s390x/s390-virtio-ccw.c         | 14 ++++++++++++-
 hw/scsi/vhost-scsi.c               |  3 ++-
 hw/scsi/vhost-user-scsi.c          |  5 +++--
 hw/scsi/virtio-scsi.c              | 13 ++++++++----
 hw/virtio/vhost-scsi-pci.c         |  9 +++++++--
 hw/virtio/vhost-user-blk-pci.c     |  4 ++++
 hw/virtio/vhost-user-scsi-pci.c    |  9 +++++++--
 hw/virtio/virtio-blk-pci.c         |  7 ++++++-
 hw/virtio/virtio-pci.c             | 32 ++++++++++++++++++++++++++++++
 hw/virtio/virtio-scsi-pci.c        |  9 +++++++--
 VERSION                            |  2 +-
 25 files changed, 184 insertions(+), 23 deletions(-)

--=20
2.26.2

[PATCH v6 1/7] Open 5.2 development tree

[Stefan Hajnoczi]

From: Peter Maydell <peter.maydell@linaro.org>

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 VERSION | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/VERSION b/VERSION
index 831446cbd2..7d40cb9d36 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-5.1.0
+5.1.50
-- 
2.26.2

[PATCH v6 2/7] hw: add 5.2 machine types and 5.1 compat options

[Stefan Hajnoczi]

arm, i386, ppc, and s390x have versioned machine types and associated
compatibility options. Introduce new ones now that QEMU 5.1 has been
released.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/hw/boards.h        |  3 +++
 include/hw/i386/pc.h       |  3 +++
 hw/arm/virt.c              |  9 ++++++++-
 hw/core/machine.c          |  4 ++++
 hw/i386/pc.c               |  4 ++++
 hw/i386/pc_piix.c          | 14 +++++++++++++-
 hw/i386/pc_q35.c           | 13 ++++++++++++-
 hw/ppc/spapr.c             | 15 +++++++++++++--
 hw/s390x/s390-virtio-ccw.c | 14 +++++++++++++-
 9 files changed, 73 insertions(+), 6 deletions(-)

diff --git a/include/hw/boards.h b/include/hw/boards.h
index 426ce5f625..bc5b82ad20 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -319,6 +319,9 @@ struct MachineState {
     } \
     type_init(machine_initfn##_register_types)
 
+extern GlobalProperty hw_compat_5_1[];
+extern const size_t hw_compat_5_1_len;
+
 extern GlobalProperty hw_compat_5_0[];
 extern const size_t hw_compat_5_0_len;
 
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 3d7ed3a55e..fe52e165b2 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -193,6 +193,9 @@ void pc_system_firmware_init(PCMachineState *pcms, MemoryRegion *rom_memory);
 void pc_madt_cpu_entry(AcpiDeviceIf *adev, int uid,
                        const CPUArchIdList *apic_ids, GArray *entry);
 
+extern GlobalProperty pc_compat_5_1[];
+extern const size_t pc_compat_5_1_len;
+
 extern GlobalProperty pc_compat_5_0[];
 extern const size_t pc_compat_5_0_len;
 
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index ecfee362a1..acf9bfbece 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2546,10 +2546,17 @@ static void machvirt_machine_init(void)
 }
 type_init(machvirt_machine_init);
 
+static void virt_machine_5_2_options(MachineClass *mc)
+{
+}
+DEFINE_VIRT_MACHINE_AS_LATEST(5, 2)
+
 static void virt_machine_5_1_options(MachineClass *mc)
 {
+    virt_machine_5_2_options(mc);
+    compat_props_add(mc->compat_props, hw_compat_5_1, hw_compat_5_1_len);
 }
-DEFINE_VIRT_MACHINE_AS_LATEST(5, 1)
+DEFINE_VIRT_MACHINE(5, 1)
 
 static void virt_machine_5_0_options(MachineClass *mc)
 {
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 8d1a90c6cf..a6f7e4e8d7 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -28,6 +28,10 @@
 #include "hw/mem/nvdimm.h"
 #include "migration/vmstate.h"
 
+GlobalProperty hw_compat_5_1[] = {
+};
+const size_t hw_compat_5_1_len = G_N_ELEMENTS(hw_compat_5_1);
+
 GlobalProperty hw_compat_5_0[] = {
     { "pci-host-bridge", "x-config-reg-migration-enabled", "off" },
     { "virtio-balloon-device", "page-poison", "false" },
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 47c5ca3e34..4afcf17f99 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -97,6 +97,10 @@
 #include "fw_cfg.h"
 #include "trace.h"
 
+GlobalProperty pc_compat_5_1[] = {
+};
+const size_t pc_compat_5_1_len = G_N_ELEMENTS(pc_compat_5_1);
+
 GlobalProperty pc_compat_5_0[] = {
 };
 const size_t pc_compat_5_0_len = G_N_ELEMENTS(pc_compat_5_0);
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index b789e83f9a..9ce1f9c5d6 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -426,7 +426,7 @@ static void pc_i440fx_machine_options(MachineClass *m)
     machine_class_allow_dynamic_sysbus_dev(m, TYPE_VMBUS_BRIDGE);
 }
 
-static void pc_i440fx_5_1_machine_options(MachineClass *m)
+static void pc_i440fx_5_2_machine_options(MachineClass *m)
 {
     PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_i440fx_machine_options(m);
@@ -435,6 +435,18 @@ static void pc_i440fx_5_1_machine_options(MachineClass *m)
     pcmc->default_cpu_version = 1;
 }
 
+DEFINE_I440FX_MACHINE(v5_2, "pc-i440fx-5.2", NULL,
+                      pc_i440fx_5_2_machine_options);
+
+static void pc_i440fx_5_1_machine_options(MachineClass *m)
+{
+    pc_i440fx_machine_options(m);
+    m->alias = NULL;
+    m->is_default = false;
+    compat_props_add(m->compat_props, hw_compat_5_1, hw_compat_5_1_len);
+    compat_props_add(m->compat_props, pc_compat_5_1, pc_compat_5_1_len);
+}
+
 DEFINE_I440FX_MACHINE(v5_1, "pc-i440fx-5.1", NULL,
                       pc_i440fx_5_1_machine_options);
 
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index a3e607a544..4acaad557c 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -353,7 +353,7 @@ static void pc_q35_machine_options(MachineClass *m)
     m->max_cpus = 288;
 }
 
-static void pc_q35_5_1_machine_options(MachineClass *m)
+static void pc_q35_5_2_machine_options(MachineClass *m)
 {
     PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_q35_machine_options(m);
@@ -361,6 +361,17 @@ static void pc_q35_5_1_machine_options(MachineClass *m)
     pcmc->default_cpu_version = 1;
 }
 
+DEFINE_Q35_MACHINE(v5_2, "pc-q35-5.2", NULL,
+                   pc_q35_5_2_machine_options);
+
+static void pc_q35_5_1_machine_options(MachineClass *m)
+{
+    pc_q35_machine_options(m);
+    m->alias = NULL;
+    compat_props_add(m->compat_props, hw_compat_5_1, hw_compat_5_1_len);
+    compat_props_add(m->compat_props, pc_compat_5_1, pc_compat_5_1_len);
+}
+
 DEFINE_Q35_MACHINE(v5_1, "pc-q35-5.1", NULL,
                    pc_q35_5_1_machine_options);
 
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 0ae293ec94..1c8d0981b3 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -4579,15 +4579,26 @@ static void spapr_machine_latest_class_options(MachineClass *mc)
     }                                                                \
     type_init(spapr_machine_register_##suffix)
 
+/*
+ * pseries-5.2
+ */
+static void spapr_machine_5_2_class_options(MachineClass *mc)
+{
+    /* Defaults for the latest behaviour inherited from the base class */
+}
+
+DEFINE_SPAPR_MACHINE(5_2, "5.2", true);
+
 /*
  * pseries-5.1
  */
 static void spapr_machine_5_1_class_options(MachineClass *mc)
 {
-    /* Defaults for the latest behaviour inherited from the base class */
+    spapr_machine_5_2_class_options(mc);
+    compat_props_add(mc->compat_props, hw_compat_5_1, hw_compat_5_1_len);
 }
 
-DEFINE_SPAPR_MACHINE(5_1, "5.1", true);
+DEFINE_SPAPR_MACHINE(5_1, "5.1", false);
 
 /*
  * pseries-5.0
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index e72c61d2ea..f4ea6a9545 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -801,14 +801,26 @@ bool css_migration_enabled(void)
     }                                                                         \
     type_init(ccw_machine_register_##suffix)
 
+static void ccw_machine_5_2_instance_options(MachineState *machine)
+{
+}
+
+static void ccw_machine_5_2_class_options(MachineClass *mc)
+{
+}
+DEFINE_CCW_MACHINE(5_2, "5.2", true);
+
 static void ccw_machine_5_1_instance_options(MachineState *machine)
 {
+    ccw_machine_5_2_instance_options(machine);
 }
 
 static void ccw_machine_5_1_class_options(MachineClass *mc)
 {
+    ccw_machine_5_2_class_options(mc);
+    compat_props_add(mc->compat_props, hw_compat_5_1, hw_compat_5_1_len);
 }
-DEFINE_CCW_MACHINE(5_1, "5.1", true);
+DEFINE_CCW_MACHINE(5_1, "5.1", false);
 
 static void ccw_machine_5_0_instance_options(MachineState *machine)
 {
-- 
2.26.2

[PATCH v6 3/7] virtio-pci: add virtio_pci_optimal_num_queues() helper

[Stefan Hajnoczi]

Multi-queue devices achieve the best performance when each vCPU has a
dedicated queue. This ensures that virtqueue used notifications are
handled on the same vCPU that submitted virtqueue buffers.  When another
vCPU handles the the notification an IPI will be necessary to wake the
submission vCPU and this incurs a performance overhead.

Provide a helper function that virtio-pci devices will use in later
patches to automatically select the optimal number of queues.

The function handles guests with large numbers of CPUs by limiting the
number of queues to fit within the following constraints:
1. The maximum number of MSI-X vectors.
2. The maximum number of virtqueues.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
---
 hw/virtio/virtio-pci.h |  9 +++++++++
 hw/virtio/virtio-pci.c | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
index e2eaaa9182..91096f0291 100644
--- a/hw/virtio/virtio-pci.h
+++ b/hw/virtio/virtio-pci.h
@@ -243,4 +243,13 @@ typedef struct VirtioPCIDeviceTypeInfo {
 /* Register virtio-pci type(s).  @t must be static. */
 void virtio_pci_types_register(const VirtioPCIDeviceTypeInfo *t);
 
+/**
+ * virtio_pci_optimal_num_queues:
+ * @fixed_queues: number of queues that are always present
+ *
+ * Returns: The optimal number of queues for a multi-queue device, excluding
+ * @fixed_queues.
+ */
+unsigned virtio_pci_optimal_num_queues(unsigned fixed_queues);
+
 #endif
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index ccdf54e81c..fc69570dcc 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -19,6 +19,7 @@
 
 #include "exec/memop.h"
 #include "standard-headers/linux/virtio_pci.h"
+#include "hw/boards.h"
 #include "hw/virtio/virtio.h"
 #include "migration/qemu-file-types.h"
 #include "hw/pci/pci.h"
@@ -2058,6 +2059,37 @@ void virtio_pci_types_register(const VirtioPCIDeviceTypeInfo *t)
     g_free(base_name);
 }
 
+unsigned virtio_pci_optimal_num_queues(unsigned fixed_queues)
+{
+    /*
+     * 1:1 vq to vCPU mapping is ideal because the same vCPU that submitted
+     * virtqueue buffers can handle their completion. When a different vCPU
+     * handles completion it may need to IPI the vCPU that submitted the
+     * request and this adds overhead.
+     *
+     * Virtqueues consume guest RAM and MSI-X vectors. This is wasteful in
+     * guests with very many vCPUs and a device that is only used by a few
+     * vCPUs. Unfortunately optimizing that case requires manual pinning inside
+     * the guest, so those users might as well manually set the number of
+     * queues. There is no upper limit that can be applied automatically and
+     * doing so arbitrarily would result in a sudden performance drop once the
+     * threshold number of vCPUs is exceeded.
+     */
+    unsigned num_queues = current_machine->smp.cpus;
+
+    /*
+     * The maximum number of MSI-X vectors is PCI_MSIX_FLAGS_QSIZE + 1, but the
+     * config change interrupt and the fixed virtqueues must be taken into
+     * account too.
+     */
+    num_queues = MIN(num_queues, PCI_MSIX_FLAGS_QSIZE - fixed_queues);
+
+    /*
+     * There is a limit to how many virtqueues a device can have.
+     */
+    return MIN(num_queues, VIRTIO_QUEUE_MAX - fixed_queues);
+}
+
 /* virtio-pci-bus */
 
 static void virtio_pci_bus_new(VirtioBusState *bus, size_t bus_size,
-- 
2.26.2

[PATCH v6 4/7] virtio-scsi: introduce a constant for fixed virtqueues

[Stefan Hajnoczi]

The event and control virtqueues are always present, regardless of the
multi-queue configuration.  Define a constant so that virtqueue number
calculations are easier to read.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
---
 include/hw/virtio/virtio-scsi.h | 3 +++
 hw/scsi/vhost-user-scsi.c       | 2 +-
 hw/scsi/virtio-scsi.c           | 7 ++++---
 hw/virtio/vhost-scsi-pci.c      | 3 ++-
 hw/virtio/vhost-user-scsi-pci.c | 3 ++-
 hw/virtio/virtio-scsi-pci.c     | 3 ++-
 6 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
index 24e768909d..9f293bcb80 100644
--- a/include/hw/virtio/virtio-scsi.h
+++ b/include/hw/virtio/virtio-scsi.h
@@ -36,6 +36,9 @@
 #define VIRTIO_SCSI_MAX_TARGET  255
 #define VIRTIO_SCSI_MAX_LUN     16383
 
+/* Number of virtqueues that are always present */
+#define VIRTIO_SCSI_VQ_NUM_FIXED    2
+
 typedef struct virtio_scsi_cmd_req VirtIOSCSICmdReq;
 typedef struct virtio_scsi_cmd_resp VirtIOSCSICmdResp;
 typedef struct virtio_scsi_ctrl_tmf_req VirtIOSCSICtrlTMFReq;
diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c
index f2e524438a..a8b821466f 100644
--- a/hw/scsi/vhost-user-scsi.c
+++ b/hw/scsi/vhost-user-scsi.c
@@ -114,7 +114,7 @@ static void vhost_user_scsi_realize(DeviceState *dev, Error **errp)
         goto free_virtio;
     }
 
-    vsc->dev.nvqs = 2 + vs->conf.num_queues;
+    vsc->dev.nvqs = VIRTIO_SCSI_VQ_NUM_FIXED + vs->conf.num_queues;
     vsc->dev.vqs = g_new0(struct vhost_virtqueue, vsc->dev.nvqs);
     vsc->dev.vq_index = 0;
     vsc->dev.backend_features = 0;
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index b49775269e..eecdd05af5 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -191,7 +191,7 @@ static void virtio_scsi_save_request(QEMUFile *f, SCSIRequest *sreq)
     VirtIOSCSIReq *req = sreq->hba_private;
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(req->dev);
     VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
-    uint32_t n = virtio_get_queue_index(req->vq) - 2;
+    uint32_t n = virtio_get_queue_index(req->vq) - VIRTIO_SCSI_VQ_NUM_FIXED;
 
     assert(n < vs->conf.num_queues);
     qemu_put_be32s(f, &n);
@@ -892,10 +892,11 @@ void virtio_scsi_common_realize(DeviceState *dev,
                 sizeof(VirtIOSCSIConfig));
 
     if (s->conf.num_queues == 0 ||
-            s->conf.num_queues > VIRTIO_QUEUE_MAX - 2) {
+            s->conf.num_queues > VIRTIO_QUEUE_MAX - VIRTIO_SCSI_VQ_NUM_FIXED) {
         error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
                          "must be a positive integer less than %d.",
-                   s->conf.num_queues, VIRTIO_QUEUE_MAX - 2);
+                   s->conf.num_queues,
+                   VIRTIO_QUEUE_MAX - VIRTIO_SCSI_VQ_NUM_FIXED);
         virtio_cleanup(vdev);
         return;
     }
diff --git a/hw/virtio/vhost-scsi-pci.c b/hw/virtio/vhost-scsi-pci.c
index 095af23f3f..06e814d30e 100644
--- a/hw/virtio/vhost-scsi-pci.c
+++ b/hw/virtio/vhost-scsi-pci.c
@@ -50,7 +50,8 @@ static void vhost_scsi_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
 
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
-        vpci_dev->nvectors = vs->conf.num_queues + 3;
+        vpci_dev->nvectors = vs->conf.num_queues +
+                             VIRTIO_SCSI_VQ_NUM_FIXED + 1;
     }
 
     qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
diff --git a/hw/virtio/vhost-user-scsi-pci.c b/hw/virtio/vhost-user-scsi-pci.c
index 4705cd54e8..ab6dfb71a9 100644
--- a/hw/virtio/vhost-user-scsi-pci.c
+++ b/hw/virtio/vhost-user-scsi-pci.c
@@ -56,7 +56,8 @@ static void vhost_user_scsi_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
 
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
-        vpci_dev->nvectors = vs->conf.num_queues + 3;
+        vpci_dev->nvectors = vs->conf.num_queues +
+                             VIRTIO_SCSI_VQ_NUM_FIXED + 1;
     }
 
     qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
diff --git a/hw/virtio/virtio-scsi-pci.c b/hw/virtio/virtio-scsi-pci.c
index c23a134202..3ff9eb7ef6 100644
--- a/hw/virtio/virtio-scsi-pci.c
+++ b/hw/virtio/virtio-scsi-pci.c
@@ -51,7 +51,8 @@ static void virtio_scsi_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     char *bus_name;
 
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
-        vpci_dev->nvectors = vs->conf.num_queues + 3;
+        vpci_dev->nvectors = vs->conf.num_queues +
+                             VIRTIO_SCSI_VQ_NUM_FIXED + 1;
     }
 
     /*
-- 
2.26.2

[PATCH v6 5/7] virtio-scsi-pci: default num_queues to -smp N

[Stefan Hajnoczi]

Automatically size the number of virtio-scsi-pci, vhost-scsi-pci, and
vhost-user-scsi-pci request virtqueues to match the number of vCPUs.
Other transports continue to default to 1 request virtqueue.

A 1:1 virtqueue:vCPU mapping ensures that completion interrupts are
handled on the same vCPU that submitted the request.  No IPI is
necessary to complete an I/O request and performance is improved.  The
maximum number of MSI-X vectors and virtqueues limit are respected.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/hw/virtio/virtio-scsi.h |  2 ++
 hw/core/machine.c               |  3 +++
 hw/scsi/vhost-scsi.c            |  3 ++-
 hw/scsi/vhost-user-scsi.c       |  3 ++-
 hw/scsi/virtio-scsi.c           |  6 +++++-
 hw/virtio/vhost-scsi-pci.c      | 10 +++++++---
 hw/virtio/vhost-user-scsi-pci.c | 10 +++++++---
 hw/virtio/virtio-scsi-pci.c     | 10 +++++++---
 8 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
index 9f293bcb80..c0b8e4dd7e 100644
--- a/include/hw/virtio/virtio-scsi.h
+++ b/include/hw/virtio/virtio-scsi.h
@@ -39,6 +39,8 @@
 /* Number of virtqueues that are always present */
 #define VIRTIO_SCSI_VQ_NUM_FIXED    2
 
+#define VIRTIO_SCSI_AUTO_NUM_QUEUES UINT32_MAX
+
 typedef struct virtio_scsi_cmd_req VirtIOSCSICmdReq;
 typedef struct virtio_scsi_cmd_resp VirtIOSCSICmdResp;
 typedef struct virtio_scsi_ctrl_tmf_req VirtIOSCSICtrlTMFReq;
diff --git a/hw/core/machine.c b/hw/core/machine.c
index a6f7e4e8d7..9ee2aa0f7b 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -29,6 +29,9 @@
 #include "migration/vmstate.h"
 
 GlobalProperty hw_compat_5_1[] = {
+    { "vhost-scsi", "num_queues", "1"},
+    { "vhost-user-scsi", "num_queues", "1"},
+    { "virtio-scsi-device", "num_queues", "1"},
 };
 const size_t hw_compat_5_1_len = G_N_ELEMENTS(hw_compat_5_1);
 
diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
index 13b05af29b..a83ffeefc8 100644
--- a/hw/scsi/vhost-scsi.c
+++ b/hw/scsi/vhost-scsi.c
@@ -270,7 +270,8 @@ static Property vhost_scsi_properties[] = {
     DEFINE_PROP_STRING("vhostfd", VirtIOSCSICommon, conf.vhostfd),
     DEFINE_PROP_STRING("wwpn", VirtIOSCSICommon, conf.wwpn),
     DEFINE_PROP_UINT32("boot_tpgt", VirtIOSCSICommon, conf.boot_tpgt, 0),
-    DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues, 1),
+    DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues,
+                       VIRTIO_SCSI_AUTO_NUM_QUEUES),
     DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSICommon, conf.virtqueue_size,
                        128),
     DEFINE_PROP_BOOL("seg_max_adjust", VirtIOSCSICommon, conf.seg_max_adjust,
diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c
index a8b821466f..7c0631656c 100644
--- a/hw/scsi/vhost-user-scsi.c
+++ b/hw/scsi/vhost-user-scsi.c
@@ -162,7 +162,8 @@ static void vhost_user_scsi_unrealize(DeviceState *dev)
 static Property vhost_user_scsi_properties[] = {
     DEFINE_PROP_CHR("chardev", VirtIOSCSICommon, conf.chardev),
     DEFINE_PROP_UINT32("boot_tpgt", VirtIOSCSICommon, conf.boot_tpgt, 0),
-    DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues, 1),
+    DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues,
+                       VIRTIO_SCSI_AUTO_NUM_QUEUES),
     DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSICommon, conf.virtqueue_size,
                        128),
     DEFINE_PROP_UINT32("max_sectors", VirtIOSCSICommon, conf.max_sectors,
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index eecdd05af5..3a71ea7097 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -891,6 +891,9 @@ void virtio_scsi_common_realize(DeviceState *dev,
     virtio_init(vdev, "virtio-scsi", VIRTIO_ID_SCSI,
                 sizeof(VirtIOSCSIConfig));
 
+    if (s->conf.num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+        s->conf.num_queues = 1;
+    }
     if (s->conf.num_queues == 0 ||
             s->conf.num_queues > VIRTIO_QUEUE_MAX - VIRTIO_SCSI_VQ_NUM_FIXED) {
         error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
@@ -964,7 +967,8 @@ static void virtio_scsi_device_unrealize(DeviceState *dev)
 }
 
 static Property virtio_scsi_properties[] = {
-    DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues, 1),
+    DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues,
+                       VIRTIO_SCSI_AUTO_NUM_QUEUES),
     DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSI,
                                          parent_obj.conf.virtqueue_size, 256),
     DEFINE_PROP_BOOL("seg_max_adjust", VirtIOSCSI,
diff --git a/hw/virtio/vhost-scsi-pci.c b/hw/virtio/vhost-scsi-pci.c
index 06e814d30e..a6bb0dc60d 100644
--- a/hw/virtio/vhost-scsi-pci.c
+++ b/hw/virtio/vhost-scsi-pci.c
@@ -47,11 +47,15 @@ static void vhost_scsi_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
 {
     VHostSCSIPCI *dev = VHOST_SCSI_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
-    VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
+    VirtIOSCSIConf *conf = &dev->vdev.parent_obj.parent_obj.conf;
+
+    if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+        conf->num_queues =
+            virtio_pci_optimal_num_queues(VIRTIO_SCSI_VQ_NUM_FIXED);
+    }
 
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
-        vpci_dev->nvectors = vs->conf.num_queues +
-                             VIRTIO_SCSI_VQ_NUM_FIXED + 1;
+        vpci_dev->nvectors = conf->num_queues + VIRTIO_SCSI_VQ_NUM_FIXED + 1;
     }
 
     qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
diff --git a/hw/virtio/vhost-user-scsi-pci.c b/hw/virtio/vhost-user-scsi-pci.c
index ab6dfb71a9..25e97ca54e 100644
--- a/hw/virtio/vhost-user-scsi-pci.c
+++ b/hw/virtio/vhost-user-scsi-pci.c
@@ -53,11 +53,15 @@ static void vhost_user_scsi_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
 {
     VHostUserSCSIPCI *dev = VHOST_USER_SCSI_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
-    VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
+    VirtIOSCSIConf *conf = &dev->vdev.parent_obj.parent_obj.conf;
+
+    if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+        conf->num_queues =
+            virtio_pci_optimal_num_queues(VIRTIO_SCSI_VQ_NUM_FIXED);
+    }
 
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
-        vpci_dev->nvectors = vs->conf.num_queues +
-                             VIRTIO_SCSI_VQ_NUM_FIXED + 1;
+        vpci_dev->nvectors = conf->num_queues + VIRTIO_SCSI_VQ_NUM_FIXED + 1;
     }
 
     qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
diff --git a/hw/virtio/virtio-scsi-pci.c b/hw/virtio/virtio-scsi-pci.c
index 3ff9eb7ef6..fa4b3bfb50 100644
--- a/hw/virtio/virtio-scsi-pci.c
+++ b/hw/virtio/virtio-scsi-pci.c
@@ -46,13 +46,17 @@ static void virtio_scsi_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
 {
     VirtIOSCSIPCI *dev = VIRTIO_SCSI_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
-    VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
     DeviceState *proxy = DEVICE(vpci_dev);
+    VirtIOSCSIConf *conf = &dev->vdev.parent_obj.conf;
     char *bus_name;
 
+    if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
+        conf->num_queues =
+            virtio_pci_optimal_num_queues(VIRTIO_SCSI_VQ_NUM_FIXED);
+    }
+
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
-        vpci_dev->nvectors = vs->conf.num_queues +
-                             VIRTIO_SCSI_VQ_NUM_FIXED + 1;
+        vpci_dev->nvectors = conf->num_queues + VIRTIO_SCSI_VQ_NUM_FIXED + 1;
     }
 
     /*
-- 
2.26.2

[PATCH v6 6/7] virtio-blk-pci: default num_queues to -smp N

[Stefan Hajnoczi]

Automatically size the number of virtio-blk-pci request virtqueues to
match the number of vCPUs.  Other transports continue to default to 1
request virtqueue.

A 1:1 virtqueue:vCPU mapping ensures that completion interrupts are
handled on the same vCPU that submitted the request.  No IPI is
necessary to complete an I/O request and performance is improved.  The
maximum number of MSI-X vectors and virtqueues limit are respected.

Performance improves from 78k to 104k IOPS on a 32 vCPU guest with 101
virtio-blk-pci devices (ioengine=libaio, iodepth=1, bs=4k, rw=randread
with NVMe storage).

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
---
 include/hw/virtio/virtio-blk.h | 2 ++
 hw/block/virtio-blk.c          | 6 +++++-
 hw/core/machine.c              | 1 +
 hw/virtio/virtio-blk-pci.c     | 7 ++++++-
 4 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index b1334c3904..7539c2b848 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -30,6 +30,8 @@ struct virtio_blk_inhdr
     unsigned char status;
 };
 
+#define VIRTIO_BLK_AUTO_NUM_QUEUES UINT16_MAX
+
 struct VirtIOBlkConf
 {
     BlockConf conf;
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 413783693c..2204ba149e 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -1147,6 +1147,9 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp)
         error_setg(errp, "Device needs media, but drive is empty");
         return;
     }
+    if (conf->num_queues == VIRTIO_BLK_AUTO_NUM_QUEUES) {
+        conf->num_queues = 1;
+    }
     if (!conf->num_queues) {
         error_setg(errp, "num-queues property must be larger than 0");
         return;
@@ -1281,7 +1284,8 @@ static Property virtio_blk_properties[] = {
 #endif
     DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0,
                     true),
-    DEFINE_PROP_UINT16("num-queues", VirtIOBlock, conf.num_queues, 1),
+    DEFINE_PROP_UINT16("num-queues", VirtIOBlock, conf.num_queues,
+                       VIRTIO_BLK_AUTO_NUM_QUEUES),
     DEFINE_PROP_UINT16("queue-size", VirtIOBlock, conf.queue_size, 256),
     DEFINE_PROP_BOOL("seg-max-adjust", VirtIOBlock, conf.seg_max_adjust, true),
     DEFINE_PROP_LINK("iothread", VirtIOBlock, conf.iothread, TYPE_IOTHREAD,
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 9ee2aa0f7b..7f65fa8743 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -31,6 +31,7 @@
 GlobalProperty hw_compat_5_1[] = {
     { "vhost-scsi", "num_queues", "1"},
     { "vhost-user-scsi", "num_queues", "1"},
+    { "virtio-blk-device", "num-queues", "1"},
     { "virtio-scsi-device", "num_queues", "1"},
 };
 const size_t hw_compat_5_1_len = G_N_ELEMENTS(hw_compat_5_1);
diff --git a/hw/virtio/virtio-blk-pci.c b/hw/virtio/virtio-blk-pci.c
index 849cc7dfd8..37c6e0aeb4 100644
--- a/hw/virtio/virtio-blk-pci.c
+++ b/hw/virtio/virtio-blk-pci.c
@@ -50,9 +50,14 @@ static void virtio_blk_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
 {
     VirtIOBlkPCI *dev = VIRTIO_BLK_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
+    VirtIOBlkConf *conf = &dev->vdev.conf;
+
+    if (conf->num_queues == VIRTIO_BLK_AUTO_NUM_QUEUES) {
+        conf->num_queues = virtio_pci_optimal_num_queues(0);
+    }
 
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
-        vpci_dev->nvectors = dev->vdev.conf.num_queues + 1;
+        vpci_dev->nvectors = conf->num_queues + 1;
     }
 
     qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
-- 
2.26.2

[PATCH v6 7/7] vhost-user-blk-pci: default num_queues to -smp N

[Stefan Hajnoczi]

Automatically size the number of request virtqueues to match the number
of vCPUs.  This ensures that completion interrupts are handled on the
same vCPU that submitted the request.  No IPI is necessary to complete
an I/O request and performance is improved.  The maximum number of MSI-X
vectors and virtqueues limit are respected.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
---
 include/hw/virtio/vhost-user-blk.h | 2 ++
 hw/block/vhost-user-blk.c          | 6 +++++-
 hw/core/machine.c                  | 1 +
 hw/virtio/vhost-user-blk-pci.c     | 4 ++++
 4 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/include/hw/virtio/vhost-user-blk.h b/include/hw/virtio/vhost-user-blk.h
index 34ad6f0c0e..292d17147c 100644
--- a/include/hw/virtio/vhost-user-blk.h
+++ b/include/hw/virtio/vhost-user-blk.h
@@ -25,6 +25,8 @@
 #define VHOST_USER_BLK(obj) \
         OBJECT_CHECK(VHostUserBlk, (obj), TYPE_VHOST_USER_BLK)
 
+#define VHOST_USER_BLK_AUTO_NUM_QUEUES UINT16_MAX
+
 typedef struct VHostUserBlk {
     VirtIODevice parent_obj;
     CharBackend chardev;
diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index a00b854736..39aec42dae 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -420,6 +420,9 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
         return;
     }
 
+    if (s->num_queues == VHOST_USER_BLK_AUTO_NUM_QUEUES) {
+        s->num_queues = 1;
+    }
     if (!s->num_queues || s->num_queues > VIRTIO_QUEUE_MAX) {
         error_setg(errp, "vhost-user-blk: invalid number of IO queues");
         return;
@@ -531,7 +534,8 @@ static const VMStateDescription vmstate_vhost_user_blk = {
 
 static Property vhost_user_blk_properties[] = {
     DEFINE_PROP_CHR("chardev", VHostUserBlk, chardev),
-    DEFINE_PROP_UINT16("num-queues", VHostUserBlk, num_queues, 1),
+    DEFINE_PROP_UINT16("num-queues", VHostUserBlk, num_queues,
+                       VHOST_USER_BLK_AUTO_NUM_QUEUES),
     DEFINE_PROP_UINT32("queue-size", VHostUserBlk, queue_size, 128),
     DEFINE_PROP_BIT("config-wce", VHostUserBlk, config_wce, 0, true),
     DEFINE_PROP_END_OF_LIST(),
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 7f65fa8743..ea26d61237 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -30,6 +30,7 @@
 
 GlobalProperty hw_compat_5_1[] = {
     { "vhost-scsi", "num_queues", "1"},
+    { "vhost-user-blk", "num-queues", "1"},
     { "vhost-user-scsi", "num_queues", "1"},
     { "virtio-blk-device", "num-queues", "1"},
     { "virtio-scsi-device", "num_queues", "1"},
diff --git a/hw/virtio/vhost-user-blk-pci.c b/hw/virtio/vhost-user-blk-pci.c
index 4f5d5cbf44..a62a71e067 100644
--- a/hw/virtio/vhost-user-blk-pci.c
+++ b/hw/virtio/vhost-user-blk-pci.c
@@ -54,6 +54,10 @@ static void vhost_user_blk_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     VHostUserBlkPCI *dev = VHOST_USER_BLK_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
 
+    if (dev->vdev.num_queues == VHOST_USER_BLK_AUTO_NUM_QUEUES) {
+        dev->vdev.num_queues = virtio_pci_optimal_num_queues(0);
+    }
+
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
         vpci_dev->nvectors = dev->vdev.num_queues + 1;
     }
-- 
2.26.2

Re: [PATCH v6 2/7] hw: add 5.2 machine types and 5.1 compat options

[Cornelia Huck]

On Tue, 18 Aug 2020 15:33:43 +0100
Stefan Hajnoczi <stefanha@redhat.com> wrote:

> arm, i386, ppc, and s390x have versioned machine types and associated
> compatibility options. Introduce new ones now that QEMU 5.1 has been
> released.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  include/hw/boards.h        |  3 +++
>  include/hw/i386/pc.h       |  3 +++
>  hw/arm/virt.c              |  9 ++++++++-
>  hw/core/machine.c          |  4 ++++
>  hw/i386/pc.c               |  4 ++++
>  hw/i386/pc_piix.c          | 14 +++++++++++++-
>  hw/i386/pc_q35.c           | 13 ++++++++++++-
>  hw/ppc/spapr.c             | 15 +++++++++++++--
>  hw/s390x/s390-virtio-ccw.c | 14 +++++++++++++-
>  9 files changed, 73 insertions(+), 6 deletions(-)

https://lore.kernel.org/qemu-devel/20200728094645.272149-1-cohuck@redhat.com/
is already out there :)

Re: [PATCH v6 5/7] virtio-scsi-pci: default num_queues to -smp N

[Cornelia Huck]

On Tue, 18 Aug 2020 15:33:46 +0100
Stefan Hajnoczi <stefanha@redhat.com> wrote:

> Automatically size the number of virtio-scsi-pci, vhost-scsi-pci, and
> vhost-user-scsi-pci request virtqueues to match the number of vCPUs.
> Other transports continue to default to 1 request virtqueue.
> 
> A 1:1 virtqueue:vCPU mapping ensures that completion interrupts are
> handled on the same vCPU that submitted the request.  No IPI is
> necessary to complete an I/O request and performance is improved.  The
> maximum number of MSI-X vectors and virtqueues limit are respected.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  include/hw/virtio/virtio-scsi.h |  2 ++
>  hw/core/machine.c               |  3 +++
>  hw/scsi/vhost-scsi.c            |  3 ++-
>  hw/scsi/vhost-user-scsi.c       |  3 ++-
>  hw/scsi/virtio-scsi.c           |  6 +++++-
>  hw/virtio/vhost-scsi-pci.c      | 10 +++++++---
>  hw/virtio/vhost-user-scsi-pci.c | 10 +++++++---
>  hw/virtio/virtio-scsi-pci.c     | 10 +++++++---
>  8 files changed, 35 insertions(+), 12 deletions(-)

Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Re: [PATCH v6 2/7] hw: add 5.2 machine types and 5.1 compat options

[Igor Mammedov]

On Tue, 18 Aug 2020 17:11:32 +0200
Cornelia Huck <cohuck@redhat.com> wrote:

> On Tue, 18 Aug 2020 15:33:43 +0100
> Stefan Hajnoczi <stefanha@redhat.com> wrote:
> 
> > arm, i386, ppc, and s390x have versioned machine types and associated
> > compatibility options. Introduce new ones now that QEMU 5.1 has been
> > released.
> > 
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > ---
> >  include/hw/boards.h        |  3 +++
> >  include/hw/i386/pc.h       |  3 +++
> >  hw/arm/virt.c              |  9 ++++++++-
> >  hw/core/machine.c          |  4 ++++
> >  hw/i386/pc.c               |  4 ++++
> >  hw/i386/pc_piix.c          | 14 +++++++++++++-
> >  hw/i386/pc_q35.c           | 13 ++++++++++++-
> >  hw/ppc/spapr.c             | 15 +++++++++++++--
> >  hw/s390x/s390-virtio-ccw.c | 14 +++++++++++++-
> >  9 files changed, 73 insertions(+), 6 deletions(-)  
> 
> https://lore.kernel.org/qemu-devel/20200728094645.272149-1-cohuck@redhat.com/
> is already out there :)

That one doesn't apply anymore (or I did something wrong when applying it),

but Stefan's version applies cleanly

> 
> 

Re: [PATCH v6 2/7] hw: add 5.2 machine types and 5.1 compat options

[Igor Mammedov]

On Tue, 18 Aug 2020 15:33:43 +0100
Stefan Hajnoczi <stefanha@redhat.com> wrote:

> arm, i386, ppc, and s390x have versioned machine types and associated
> compatibility options. Introduce new ones now that QEMU 5.1 has been
> released.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Reviewed-by: Igor Mammedov <imammedo@redhat.com>

> ---
>  include/hw/boards.h        |  3 +++
>  include/hw/i386/pc.h       |  3 +++
>  hw/arm/virt.c              |  9 ++++++++-
>  hw/core/machine.c          |  4 ++++
>  hw/i386/pc.c               |  4 ++++
>  hw/i386/pc_piix.c          | 14 +++++++++++++-
>  hw/i386/pc_q35.c           | 13 ++++++++++++-
>  hw/ppc/spapr.c             | 15 +++++++++++++--
>  hw/s390x/s390-virtio-ccw.c | 14 +++++++++++++-
>  9 files changed, 73 insertions(+), 6 deletions(-)
> 
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 426ce5f625..bc5b82ad20 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -319,6 +319,9 @@ struct MachineState {
>      } \
>      type_init(machine_initfn##_register_types)
>  
> +extern GlobalProperty hw_compat_5_1[];
> +extern const size_t hw_compat_5_1_len;
> +
>  extern GlobalProperty hw_compat_5_0[];
>  extern const size_t hw_compat_5_0_len;
>  
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index 3d7ed3a55e..fe52e165b2 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -193,6 +193,9 @@ void pc_system_firmware_init(PCMachineState *pcms, MemoryRegion *rom_memory);
>  void pc_madt_cpu_entry(AcpiDeviceIf *adev, int uid,
>                         const CPUArchIdList *apic_ids, GArray *entry);
>  
> +extern GlobalProperty pc_compat_5_1[];
> +extern const size_t pc_compat_5_1_len;
> +
>  extern GlobalProperty pc_compat_5_0[];
>  extern const size_t pc_compat_5_0_len;
>  
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index ecfee362a1..acf9bfbece 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2546,10 +2546,17 @@ static void machvirt_machine_init(void)
>  }
>  type_init(machvirt_machine_init);
>  
> +static void virt_machine_5_2_options(MachineClass *mc)
> +{
> +}
> +DEFINE_VIRT_MACHINE_AS_LATEST(5, 2)
> +
>  static void virt_machine_5_1_options(MachineClass *mc)
>  {
> +    virt_machine_5_2_options(mc);
> +    compat_props_add(mc->compat_props, hw_compat_5_1, hw_compat_5_1_len);
>  }
> -DEFINE_VIRT_MACHINE_AS_LATEST(5, 1)
> +DEFINE_VIRT_MACHINE(5, 1)
>  
>  static void virt_machine_5_0_options(MachineClass *mc)
>  {
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index 8d1a90c6cf..a6f7e4e8d7 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -28,6 +28,10 @@
>  #include "hw/mem/nvdimm.h"
>  #include "migration/vmstate.h"
>  
> +GlobalProperty hw_compat_5_1[] = {
> +};
> +const size_t hw_compat_5_1_len = G_N_ELEMENTS(hw_compat_5_1);
> +
>  GlobalProperty hw_compat_5_0[] = {
>      { "pci-host-bridge", "x-config-reg-migration-enabled", "off" },
>      { "virtio-balloon-device", "page-poison", "false" },
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 47c5ca3e34..4afcf17f99 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -97,6 +97,10 @@
>  #include "fw_cfg.h"
>  #include "trace.h"
>  
> +GlobalProperty pc_compat_5_1[] = {
> +};
> +const size_t pc_compat_5_1_len = G_N_ELEMENTS(pc_compat_5_1);
> +
>  GlobalProperty pc_compat_5_0[] = {
>  };
>  const size_t pc_compat_5_0_len = G_N_ELEMENTS(pc_compat_5_0);
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index b789e83f9a..9ce1f9c5d6 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -426,7 +426,7 @@ static void pc_i440fx_machine_options(MachineClass *m)
>      machine_class_allow_dynamic_sysbus_dev(m, TYPE_VMBUS_BRIDGE);
>  }
>  
> -static void pc_i440fx_5_1_machine_options(MachineClass *m)
> +static void pc_i440fx_5_2_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
>      pc_i440fx_machine_options(m);
> @@ -435,6 +435,18 @@ static void pc_i440fx_5_1_machine_options(MachineClass *m)
>      pcmc->default_cpu_version = 1;
>  }
>  
> +DEFINE_I440FX_MACHINE(v5_2, "pc-i440fx-5.2", NULL,
> +                      pc_i440fx_5_2_machine_options);
> +
> +static void pc_i440fx_5_1_machine_options(MachineClass *m)
> +{
> +    pc_i440fx_machine_options(m);
> +    m->alias = NULL;
> +    m->is_default = false;
> +    compat_props_add(m->compat_props, hw_compat_5_1, hw_compat_5_1_len);
> +    compat_props_add(m->compat_props, pc_compat_5_1, pc_compat_5_1_len);
> +}
> +
>  DEFINE_I440FX_MACHINE(v5_1, "pc-i440fx-5.1", NULL,
>                        pc_i440fx_5_1_machine_options);
>  
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index a3e607a544..4acaad557c 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -353,7 +353,7 @@ static void pc_q35_machine_options(MachineClass *m)
>      m->max_cpus = 288;
>  }
>  
> -static void pc_q35_5_1_machine_options(MachineClass *m)
> +static void pc_q35_5_2_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
>      pc_q35_machine_options(m);
> @@ -361,6 +361,17 @@ static void pc_q35_5_1_machine_options(MachineClass *m)
>      pcmc->default_cpu_version = 1;
>  }
>  
> +DEFINE_Q35_MACHINE(v5_2, "pc-q35-5.2", NULL,
> +                   pc_q35_5_2_machine_options);
> +
> +static void pc_q35_5_1_machine_options(MachineClass *m)
> +{
> +    pc_q35_machine_options(m);
> +    m->alias = NULL;
> +    compat_props_add(m->compat_props, hw_compat_5_1, hw_compat_5_1_len);
> +    compat_props_add(m->compat_props, pc_compat_5_1, pc_compat_5_1_len);
> +}
> +
>  DEFINE_Q35_MACHINE(v5_1, "pc-q35-5.1", NULL,
>                     pc_q35_5_1_machine_options);
>  
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 0ae293ec94..1c8d0981b3 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -4579,15 +4579,26 @@ static void spapr_machine_latest_class_options(MachineClass *mc)
>      }                                                                \
>      type_init(spapr_machine_register_##suffix)
>  
> +/*
> + * pseries-5.2
> + */
> +static void spapr_machine_5_2_class_options(MachineClass *mc)
> +{
> +    /* Defaults for the latest behaviour inherited from the base class */
> +}
> +
> +DEFINE_SPAPR_MACHINE(5_2, "5.2", true);
> +
>  /*
>   * pseries-5.1
>   */
>  static void spapr_machine_5_1_class_options(MachineClass *mc)
>  {
> -    /* Defaults for the latest behaviour inherited from the base class */
> +    spapr_machine_5_2_class_options(mc);
> +    compat_props_add(mc->compat_props, hw_compat_5_1, hw_compat_5_1_len);
>  }
>  
> -DEFINE_SPAPR_MACHINE(5_1, "5.1", true);
> +DEFINE_SPAPR_MACHINE(5_1, "5.1", false);
>  
>  /*
>   * pseries-5.0
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index e72c61d2ea..f4ea6a9545 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -801,14 +801,26 @@ bool css_migration_enabled(void)
>      }                                                                         \
>      type_init(ccw_machine_register_##suffix)
>  
> +static void ccw_machine_5_2_instance_options(MachineState *machine)
> +{
> +}
> +
> +static void ccw_machine_5_2_class_options(MachineClass *mc)
> +{
> +}
> +DEFINE_CCW_MACHINE(5_2, "5.2", true);
> +
>  static void ccw_machine_5_1_instance_options(MachineState *machine)
>  {
> +    ccw_machine_5_2_instance_options(machine);
>  }
>  
>  static void ccw_machine_5_1_class_options(MachineClass *mc)
>  {
> +    ccw_machine_5_2_class_options(mc);
> +    compat_props_add(mc->compat_props, hw_compat_5_1, hw_compat_5_1_len);
>  }
> -DEFINE_CCW_MACHINE(5_1, "5.1", true);
> +DEFINE_CCW_MACHINE(5_1, "5.1", false);
>  
>  static void ccw_machine_5_0_instance_options(MachineState *machine)
>  {

i

Re: [PATCH v6 2/7] hw: add 5.2 machine types and 5.1 compat options

[Cornelia Huck]

On Wed, 19 Aug 2020 14:54:25 +0200
Igor Mammedov <imammedo@redhat.com> wrote:

> On Tue, 18 Aug 2020 17:11:32 +0200
> Cornelia Huck <cohuck@redhat.com> wrote:
> 
> > On Tue, 18 Aug 2020 15:33:43 +0100
> > Stefan Hajnoczi <stefanha@redhat.com> wrote:
> >   
> > > arm, i386, ppc, and s390x have versioned machine types and associated
> > > compatibility options. Introduce new ones now that QEMU 5.1 has been
> > > released.
> > > 
> > > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > > ---
> > >  include/hw/boards.h        |  3 +++
> > >  include/hw/i386/pc.h       |  3 +++
> > >  hw/arm/virt.c              |  9 ++++++++-
> > >  hw/core/machine.c          |  4 ++++
> > >  hw/i386/pc.c               |  4 ++++
> > >  hw/i386/pc_piix.c          | 14 +++++++++++++-
> > >  hw/i386/pc_q35.c           | 13 ++++++++++++-
> > >  hw/ppc/spapr.c             | 15 +++++++++++++--
> > >  hw/s390x/s390-virtio-ccw.c | 14 +++++++++++++-
> > >  9 files changed, 73 insertions(+), 6 deletions(-)    
> > 
> > https://lore.kernel.org/qemu-devel/20200728094645.272149-1-cohuck@redhat.com/
> > is already out there :)  
> 
> That one doesn't apply anymore (or I did something wrong when applying it),
> 
> but Stefan's version applies cleanly

Seems that there were some changes afterwards. I'd prefer to just
respin mine, though.

Re: [PATCH v6 2/7] hw: add 5.2 machine types and 5.1 compat options

[Stefan Hajnoczi]

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On Tue, Aug 18, 2020 at 05:11:32PM +0200, Cornelia Huck wrote:
> On Tue, 18 Aug 2020 15:33:43 +0100
> Stefan Hajnoczi <stefanha@redhat.com> wrote:
> 
> > arm, i386, ppc, and s390x have versioned machine types and associated
> > compatibility options. Introduce new ones now that QEMU 5.1 has been
> > released.
> > 
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > ---
> >  include/hw/boards.h        |  3 +++
> >  include/hw/i386/pc.h       |  3 +++
> >  hw/arm/virt.c              |  9 ++++++++-
> >  hw/core/machine.c          |  4 ++++
> >  hw/i386/pc.c               |  4 ++++
> >  hw/i386/pc_piix.c          | 14 +++++++++++++-
> >  hw/i386/pc_q35.c           | 13 ++++++++++++-
> >  hw/ppc/spapr.c             | 15 +++++++++++++--
> >  hw/s390x/s390-virtio-ccw.c | 14 +++++++++++++-
> >  9 files changed, 73 insertions(+), 6 deletions(-)
> 
> https://lore.kernel.org/qemu-devel/20200728094645.272149-1-cohuck@redhat.com/
> is already out there :)

You're too quick! :)

Next time I'll write a script and monitor qemu.git for the release tag
so I can be first!!!!!!111

Stefan

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Re: [PATCH v6 1/7] Open 5.2 development tree

[Stefan Hajnoczi]

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On Tue, Aug 18, 2020 at 03:33:42PM +0100, Stefan Hajnoczi wrote:
> From: Peter Maydell <peter.maydell@linaro.org>
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  VERSION | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/VERSION b/VERSION
> index 831446cbd2..7d40cb9d36 100644
> --- a/VERSION
> +++ b/VERSION
> @@ -1 +1 @@
> -5.1.0
> +5.1.50
> -- 
> 2.26.2

This patch was sent by accident, please skip it when applying the
series. Git should do that automatically.

Stefan

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Re: [PATCH v6 2/7] hw: add 5.2 machine types and 5.1 compat options

[Laszlo Ersek]

On 08/19/20 16:12, Stefan Hajnoczi wrote:
> On Tue, Aug 18, 2020 at 05:11:32PM +0200, Cornelia Huck wrote:
>> On Tue, 18 Aug 2020 15:33:43 +0100
>> Stefan Hajnoczi <stefanha@redhat.com> wrote:
>>
>>> arm, i386, ppc, and s390x have versioned machine types and associated
>>> compatibility options. Introduce new ones now that QEMU 5.1 has been
>>> released.
>>>
>>> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
>>> ---
>>>  include/hw/boards.h        |  3 +++
>>>  include/hw/i386/pc.h       |  3 +++
>>>  hw/arm/virt.c              |  9 ++++++++-
>>>  hw/core/machine.c          |  4 ++++
>>>  hw/i386/pc.c               |  4 ++++
>>>  hw/i386/pc_piix.c          | 14 +++++++++++++-
>>>  hw/i386/pc_q35.c           | 13 ++++++++++++-
>>>  hw/ppc/spapr.c             | 15 +++++++++++++--
>>>  hw/s390x/s390-virtio-ccw.c | 14 +++++++++++++-
>>>  9 files changed, 73 insertions(+), 6 deletions(-)
>>
>> https://lore.kernel.org/qemu-devel/20200728094645.272149-1-cohuck@redhat.com/
>> is already out there :)
> 
> You're too quick! :)
> 
> Next time I'll write a script and monitor qemu.git for the release tag
> so I can be first!!!!!!111

You're joking, but a template patch or some other automatism that opens
the next development tree *BY* introducing new machine types would be
nothing to frown at.

Another option would be for Peter to delay opening up the next
development tree until he could immediately merge a patch with the new
machine types (posted by whoever, near the end of the HFF or something).

Thanks
Laszlo

Re: [PATCH v6 2/7] hw: add 5.2 machine types and 5.1 compat options

[Philippe Mathieu-Daudé]

On 8/19/20 4:38 PM, Laszlo Ersek wrote:
> On 08/19/20 16:12, Stefan Hajnoczi wrote:
>> On Tue, Aug 18, 2020 at 05:11:32PM +0200, Cornelia Huck wrote:
>>> On Tue, 18 Aug 2020 15:33:43 +0100
>>> Stefan Hajnoczi <stefanha@redhat.com> wrote:
>>>
>>>> arm, i386, ppc, and s390x have versioned machine types and associated
>>>> compatibility options. Introduce new ones now that QEMU 5.1 has been
>>>> released.
>>>>
>>>> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
>>>> ---
>>>>  include/hw/boards.h        |  3 +++
>>>>  include/hw/i386/pc.h       |  3 +++
>>>>  hw/arm/virt.c              |  9 ++++++++-
>>>>  hw/core/machine.c          |  4 ++++
>>>>  hw/i386/pc.c               |  4 ++++
>>>>  hw/i386/pc_piix.c          | 14 +++++++++++++-
>>>>  hw/i386/pc_q35.c           | 13 ++++++++++++-
>>>>  hw/ppc/spapr.c             | 15 +++++++++++++--
>>>>  hw/s390x/s390-virtio-ccw.c | 14 +++++++++++++-
>>>>  9 files changed, 73 insertions(+), 6 deletions(-)
>>>
>>> https://lore.kernel.org/qemu-devel/20200728094645.272149-1-cohuck@redhat.com/
>>> is already out there :)
>>
>> You're too quick! :)
>>
>> Next time I'll write a script and monitor qemu.git for the release tag
>> so I can be first!!!!!!111
> 
> You're joking, but a template patch or some other automatism that opens
> the next development tree *BY* introducing new machine types would be
> nothing to frown at.
> 
> Another option would be for Peter to delay opening up the next
> development tree until he could immediately merge a patch with the new
> machine types (posted by whoever, near the end of the HFF or something).

Or this can be the "Open the tree for development" first patch :)

> 
> Thanks
> Laszlo
> 
> 

Re: [PATCH v6 5/7] virtio-scsi-pci: default num_queues to -smp N

[Raphael Norwitz]

On Tue, Aug 18, 2020 at 11:32 AM Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> Automatically size the number of virtio-scsi-pci, vhost-scsi-pci, and
> vhost-user-scsi-pci request virtqueues to match the number of vCPUs.
> Other transports continue to default to 1 request virtqueue.
>
> A 1:1 virtqueue:vCPU mapping ensures that completion interrupts are
> handled on the same vCPU that submitted the request.  No IPI is
> necessary to complete an I/O request and performance is improved.  The
> maximum number of MSI-X vectors and virtqueues limit are respected.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>

> ---
>  include/hw/virtio/virtio-scsi.h |  2 ++
>  hw/core/machine.c               |  3 +++
>  hw/scsi/vhost-scsi.c            |  3 ++-
>  hw/scsi/vhost-user-scsi.c       |  3 ++-
>  hw/scsi/virtio-scsi.c           |  6 +++++-
>  hw/virtio/vhost-scsi-pci.c      | 10 +++++++---
>  hw/virtio/vhost-user-scsi-pci.c | 10 +++++++---
>  hw/virtio/virtio-scsi-pci.c     | 10 +++++++---
>  8 files changed, 35 insertions(+), 12 deletions(-)
>
> diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
> index 9f293bcb80..c0b8e4dd7e 100644
> --- a/include/hw/virtio/virtio-scsi.h
> +++ b/include/hw/virtio/virtio-scsi.h
> @@ -39,6 +39,8 @@
>  /* Number of virtqueues that are always present */
>  #define VIRTIO_SCSI_VQ_NUM_FIXED    2
>
> +#define VIRTIO_SCSI_AUTO_NUM_QUEUES UINT32_MAX
> +
>  typedef struct virtio_scsi_cmd_req VirtIOSCSICmdReq;
>  typedef struct virtio_scsi_cmd_resp VirtIOSCSICmdResp;
>  typedef struct virtio_scsi_ctrl_tmf_req VirtIOSCSICtrlTMFReq;
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index a6f7e4e8d7..9ee2aa0f7b 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -29,6 +29,9 @@
>  #include "migration/vmstate.h"
>
>  GlobalProperty hw_compat_5_1[] = {
> +    { "vhost-scsi", "num_queues", "1"},
> +    { "vhost-user-scsi", "num_queues", "1"},
> +    { "virtio-scsi-device", "num_queues", "1"},
>  };
>  const size_t hw_compat_5_1_len = G_N_ELEMENTS(hw_compat_5_1);
>
> diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
> index 13b05af29b..a83ffeefc8 100644
> --- a/hw/scsi/vhost-scsi.c
> +++ b/hw/scsi/vhost-scsi.c
> @@ -270,7 +270,8 @@ static Property vhost_scsi_properties[] = {
>      DEFINE_PROP_STRING("vhostfd", VirtIOSCSICommon, conf.vhostfd),
>      DEFINE_PROP_STRING("wwpn", VirtIOSCSICommon, conf.wwpn),
>      DEFINE_PROP_UINT32("boot_tpgt", VirtIOSCSICommon, conf.boot_tpgt, 0),
> -    DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues, 1),
> +    DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues,
> +                       VIRTIO_SCSI_AUTO_NUM_QUEUES),
>      DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSICommon, conf.virtqueue_size,
>                         128),
>      DEFINE_PROP_BOOL("seg_max_adjust", VirtIOSCSICommon, conf.seg_max_adjust,
> diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c
> index a8b821466f..7c0631656c 100644
> --- a/hw/scsi/vhost-user-scsi.c
> +++ b/hw/scsi/vhost-user-scsi.c
> @@ -162,7 +162,8 @@ static void vhost_user_scsi_unrealize(DeviceState *dev)
>  static Property vhost_user_scsi_properties[] = {
>      DEFINE_PROP_CHR("chardev", VirtIOSCSICommon, conf.chardev),
>      DEFINE_PROP_UINT32("boot_tpgt", VirtIOSCSICommon, conf.boot_tpgt, 0),
> -    DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues, 1),
> +    DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues,
> +                       VIRTIO_SCSI_AUTO_NUM_QUEUES),
>      DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSICommon, conf.virtqueue_size,
>                         128),
>      DEFINE_PROP_UINT32("max_sectors", VirtIOSCSICommon, conf.max_sectors,
> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> index eecdd05af5..3a71ea7097 100644
> --- a/hw/scsi/virtio-scsi.c
> +++ b/hw/scsi/virtio-scsi.c
> @@ -891,6 +891,9 @@ void virtio_scsi_common_realize(DeviceState *dev,
>      virtio_init(vdev, "virtio-scsi", VIRTIO_ID_SCSI,
>                  sizeof(VirtIOSCSIConfig));
>
> +    if (s->conf.num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
> +        s->conf.num_queues = 1;
> +    }
>      if (s->conf.num_queues == 0 ||
>              s->conf.num_queues > VIRTIO_QUEUE_MAX - VIRTIO_SCSI_VQ_NUM_FIXED) {
>          error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
> @@ -964,7 +967,8 @@ static void virtio_scsi_device_unrealize(DeviceState *dev)
>  }
>
>  static Property virtio_scsi_properties[] = {
> -    DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues, 1),
> +    DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues,
> +                       VIRTIO_SCSI_AUTO_NUM_QUEUES),
>      DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSI,
>                                           parent_obj.conf.virtqueue_size, 256),
>      DEFINE_PROP_BOOL("seg_max_adjust", VirtIOSCSI,
> diff --git a/hw/virtio/vhost-scsi-pci.c b/hw/virtio/vhost-scsi-pci.c
> index 06e814d30e..a6bb0dc60d 100644
> --- a/hw/virtio/vhost-scsi-pci.c
> +++ b/hw/virtio/vhost-scsi-pci.c
> @@ -47,11 +47,15 @@ static void vhost_scsi_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
>  {
>      VHostSCSIPCI *dev = VHOST_SCSI_PCI(vpci_dev);
>      DeviceState *vdev = DEVICE(&dev->vdev);
> -    VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
> +    VirtIOSCSIConf *conf = &dev->vdev.parent_obj.parent_obj.conf;
> +
> +    if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
> +        conf->num_queues =
> +            virtio_pci_optimal_num_queues(VIRTIO_SCSI_VQ_NUM_FIXED);
> +    }
>
>      if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
> -        vpci_dev->nvectors = vs->conf.num_queues +
> -                             VIRTIO_SCSI_VQ_NUM_FIXED + 1;
> +        vpci_dev->nvectors = conf->num_queues + VIRTIO_SCSI_VQ_NUM_FIXED + 1;
>      }
>
>      qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
> diff --git a/hw/virtio/vhost-user-scsi-pci.c b/hw/virtio/vhost-user-scsi-pci.c
> index ab6dfb71a9..25e97ca54e 100644
> --- a/hw/virtio/vhost-user-scsi-pci.c
> +++ b/hw/virtio/vhost-user-scsi-pci.c
> @@ -53,11 +53,15 @@ static void vhost_user_scsi_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
>  {
>      VHostUserSCSIPCI *dev = VHOST_USER_SCSI_PCI(vpci_dev);
>      DeviceState *vdev = DEVICE(&dev->vdev);
> -    VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
> +    VirtIOSCSIConf *conf = &dev->vdev.parent_obj.parent_obj.conf;
> +
> +    if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
> +        conf->num_queues =
> +            virtio_pci_optimal_num_queues(VIRTIO_SCSI_VQ_NUM_FIXED);
> +    }
>
>      if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
> -        vpci_dev->nvectors = vs->conf.num_queues +
> -                             VIRTIO_SCSI_VQ_NUM_FIXED + 1;
> +        vpci_dev->nvectors = conf->num_queues + VIRTIO_SCSI_VQ_NUM_FIXED + 1;
>      }
>
>      qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
> diff --git a/hw/virtio/virtio-scsi-pci.c b/hw/virtio/virtio-scsi-pci.c
> index 3ff9eb7ef6..fa4b3bfb50 100644
> --- a/hw/virtio/virtio-scsi-pci.c
> +++ b/hw/virtio/virtio-scsi-pci.c
> @@ -46,13 +46,17 @@ static void virtio_scsi_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
>  {
>      VirtIOSCSIPCI *dev = VIRTIO_SCSI_PCI(vpci_dev);
>      DeviceState *vdev = DEVICE(&dev->vdev);
> -    VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
>      DeviceState *proxy = DEVICE(vpci_dev);
> +    VirtIOSCSIConf *conf = &dev->vdev.parent_obj.conf;
>      char *bus_name;
>
> +    if (conf->num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
> +        conf->num_queues =
> +            virtio_pci_optimal_num_queues(VIRTIO_SCSI_VQ_NUM_FIXED);
> +    }
> +
>      if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
> -        vpci_dev->nvectors = vs->conf.num_queues +
> -                             VIRTIO_SCSI_VQ_NUM_FIXED + 1;
> +        vpci_dev->nvectors = conf->num_queues + VIRTIO_SCSI_VQ_NUM_FIXED + 1;
>      }
>
>      /*
> --
> 2.26.2
>