From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57649) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ymvx2-0001Wj-Aq for qemu-devel@nongnu.org; Mon, 27 Apr 2015 23:12:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ymvwy-0000hP-0s for qemu-devel@nongnu.org; Mon, 27 Apr 2015 23:12:48 -0400 Date: Tue, 28 Apr 2015 11:12:10 +0800 From: Jason Wang Message-Id: <1430190730.9163.1@smtp.corp.redhat.com> In-Reply-To: <20150427130035-mutt-send-email-mst@redhat.com> References: <1429770109-23873-1-git-send-email-jasowang@redhat.com> <1429770109-23873-16-git-send-email-jasowang@redhat.com> <20150427130035-mutt-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Subject: Re: [Qemu-devel] [PATCH V7 15/16] virtio-pci: increase the maximum number of virtqueues to 513 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Paolo Bonzini , Alexander Graf , qemu-ppc@nongnu.org, qemu-devel@nongnu.org, Richard Henderson On Mon, Apr 27, 2015 at 7:02 PM, Michael S. Tsirkin wrote: > On Thu, Apr 23, 2015 at 02:21:48PM +0800, Jason Wang wrote: >> 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 on recent Linux host (which supports up to 256 tuntap queue >> pairs). >> >> To keep migration compatibility, 64 was kept for legacy machine >> types. This is because qemu in fact allows guest to probe the limit >> of >> virtqueues through trying to set queue_sel. So for legacy machine >> type, we should make sure setting queue_sel to more than 63 won't >> make effect. > > This isn't a documented interface, and no guest that I know of does > this. Accordingly, I think we should drop everything except the > hw/virtio/virtio-pci.c change. We leave a chance for guest to use such undocumented behavior, so technically we'd better keep it and it maybe too late for us to fix if we find such a guest in the future. And consider keeping this compatibility was really not hard, so I suggest to include this. > > >> Cc: Paolo Bonzini >> Cc: Richard Henderson >> Cc: Michael S. Tsirkin >> Cc: Alexander Graf >> Cc: qemu-ppc@nongnu.org >> Signed-off-by: Jason Wang >> --- >> hw/i386/pc_piix.c | 5 +++++ >> hw/i386/pc_q35.c | 5 +++++ >> hw/ppc/spapr.c | 5 +++++ >> hw/virtio/virtio-pci.c | 6 +++++- >> 4 files changed, 20 insertions(+), 1 deletion(-) >> >> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c >> index 212e263..6e098ce 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 "hw/virtio/virtio-bus.h" >> #ifdef CONFIG_XEN >> # include >> #endif >> @@ -312,6 +313,10 @@ static void pc_init_pci(MachineState *machine) >> >> static void pc_compat_2_3(MachineState *machine) >> { >> + ObjectClass *klass = object_class_by_name("virtio-pci-bus"); >> + VirtioBusClass *k = VIRTIO_BUS_CLASS(klass); >> + >> + k->queue_max = 64; >> } >> >> static void pc_compat_2_2(MachineState *machine) >> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c >> index e67f2de..ff7c414 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 >> @@ -291,6 +292,10 @@ static void pc_q35_init(MachineState *machine) >> >> static void pc_compat_2_3(MachineState *machine) >> { >> + ObjectClass *klass = object_class_by_name("virtio-pci-bus"); >> + VirtioBusClass *k = VIRTIO_BUS_CLASS(klass); >> + >> + k->queue_max = 64; >> } >> >> static void pc_compat_2_2(MachineState *machine) >> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c >> index 8e43aa2..ee8f6a3 100644 >> --- a/hw/ppc/spapr.c >> +++ b/hw/ppc/spapr.c >> @@ -50,6 +50,7 @@ >> #include "hw/pci/pci.h" >> #include "hw/scsi/scsi.h" >> #include "hw/virtio/virtio-scsi.h" >> +#include "hw/virtio/virtio-bus.h" >> >> #include "exec/address-spaces.h" >> #include "hw/usb.h" >> @@ -1827,6 +1828,10 @@ static const TypeInfo spapr_machine_info = { >> >> static void spapr_compat_2_3(Object *obj) >> { >> + ObjectClass *klass = object_class_by_name("virtio-pci-bus"); >> + VirtioBusClass *k = VIRTIO_BUS_CLASS(klass); >> + >> + k->queue_max = 64; >> } >> >> static void spapr_compat_2_2(Object *obj) >> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c >> index 7d01500..c510cb7 100644 >> --- a/hw/virtio/virtio-pci.c >> +++ b/hw/virtio/virtio-pci.c >> @@ -42,7 +42,11 @@ >> * configuration space */ >> #define VIRTIO_PCI_CONFIG_SIZE(dev) >> VIRTIO_PCI_CONFIG_OFF(msix_enabled(dev)) >> >> -#define VIRTIO_PCI_QUEUE_MAX 64 >> +/* The number was chose to be greater than both the the number of >> max >> + * vcpus supported by host and the number of max tuntap queues >> support >> + * by host and also leave some spaces for future. >> + */ >> +#define VIRTIO_PCI_QUEUE_MAX 1024 >> >> static void virtio_pci_bus_new(VirtioBusState *bus, size_t >> bus_size, >> VirtIOPCIProxy *dev); >> -- >> 2.1.0