[Qemu-devel] [PATCH V2 09/11] virtio-pci: increase the maximum number of virtqueues to 513

[Jason Wang]

This patch increases the maximum number of virtqueues for pci from 64
to 513. This will allow booting a virtio-net-pci device with 256 queue
pairs.

To keep migration compatibility, 64 was kept for legacy machine types.

Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: Richard Henderson <r...@twiddle.net>
Cc: Anthony Liguori <aligu...@amazon.com>
Cc: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Jason Wang <jasow...@redhat.com>
---
 hw/i386/pc_piix.c          | 6 ++++++
 hw/i386/pc_q35.c           | 5 +++++
 include/hw/virtio/virtio.h | 2 +-
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 38b42b0..821d44c 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -49,6 +49,7 @@
 #include "hw/acpi/acpi.h"
 #include "cpu.h"
 #include "qemu/error-report.h"
+#include "include/hw/virtio/virtio-bus.h"
 #ifdef CONFIG_XEN
 #  include <xen/hvm/hvm_info_table.h>
 #endif
@@ -310,6 +311,11 @@ static void pc_init_pci(MachineState *machine)
 
 static void pc_compat_2_2(MachineState *machine)
 {
+    ObjectClass *klass = object_class_by_name("virtio-pci-bus");
+    VirtioBusClass *k = VIRTIO_BUS_CLASS(klass);
+
+    k->queue_max = 64;
+
     x86_cpu_compat_set_features("kvm64", FEAT_1_EDX, 0, CPUID_VME);
     x86_cpu_compat_set_features("kvm32", FEAT_1_EDX, 0, CPUID_VME);
     x86_cpu_compat_set_features("Conroe", FEAT_1_EDX, 0, CPUID_VME);
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 63027ee..dc5ada4 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -45,6 +45,7 @@
 #include "hw/usb.h"
 #include "hw/cpu/icc_bus.h"
 #include "qemu/error-report.h"
+#include "include/hw/virtio/virtio-bus.h"
 
 /* ICH9 AHCI has 6 ports */
 #define MAX_SATA_PORTS     6
@@ -289,6 +290,10 @@ static void pc_q35_init(MachineState *machine)
 
 static void pc_compat_2_2(MachineState *machine)
 {
+    ObjectClass *klass = object_class_by_name("virtio-pci-bus");
+    VirtioBusClass *k = VIRTIO_BUS_CLASS(klass);
+
+    k->queue_max = 64;
     x86_cpu_compat_set_features("kvm64", FEAT_1_EDX, 0, CPUID_VME);
     x86_cpu_compat_set_features("kvm32", FEAT_1_EDX, 0, CPUID_VME);
     x86_cpu_compat_set_features("Conroe", FEAT_1_EDX, 0, CPUID_VME);
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index e538f5a..c653ad1 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -92,7 +92,7 @@ typedef struct VirtQueueElement
     struct iovec out_sg[VIRTQUEUE_MAX_SIZE];
 } VirtQueueElement;
 
-#define VIRTIO_PCI_QUEUE_MAX 64
+#define VIRTIO_PCI_QUEUE_MAX 513
 #define VIRTIO_CCW_QUEUE_MAX 64
 #define VIRTIO_S390_QUEUE_MAX 64
 #define VIRTIO_MMIO_QUEUE_MAX 64
-- 
1.9.1