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Re: [Qemu-devel] [PATCH V4 19/19] virtio-pci: introduce auto_msix_bar_si
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH V4 19/19] virtio-pci: introduce auto_msix_bar_size property |
Date: |
Wed, 18 Mar 2015 13:57:44 +0100 |
On Wed, Mar 18, 2015 at 05:35:09PM +0800, Jason Wang wrote:
> Currently we don't support more than 128 MSI-X vectors for a pci
> devices, trying to use vector=129 for a virtio-net-pci device may get:
>
> qemu-system-x86_64: -device virtio-net-pci,netdev=hn0,vectors=129:
> unable to init msix vectors to 129
>
> This this because the MSI-X bar size were hard-coded as 4096. So this
> patch introduces boolean auto_msix_bar_size property for
> virito-pci devices. Enable this will let the device calculate the msix
> bar size based on the number of MSI-X entries instead of previous 4096
> hard-coded limit.
>
> This is a must to let virtio-net can up to 256 queues and each queue
> were associated with a specific MSI-X entry.
>
> Cc: Paolo Bonzini <address@hidden>
> Cc: Richard Henderson <address@hidden>
> Cc: Michael S. Tsirkin <address@hidden>
> Cc: Alexander Graf <address@hidden>
> Cc: address@hidden
> Signed-off-by: Jason Wang <address@hidden>
I don't understand what this property does.
What if I *don't* set auto_msix_bar_size?
vectors<=128 works exactly like it dif previously, vectors=129 fails?
Does not seem like useful behaviour, to me.
> ---
> hw/i386/pc_piix.c | 8 ++++++++
> hw/i386/pc_q35.c | 8 ++++++++
> hw/ppc/spapr.c | 11 ++++++++++-
> hw/virtio/virtio-pci.c | 17 +++++++++++++++--
> hw/virtio/virtio-pci.h | 3 +++
> include/hw/compat.h | 11 +++++++++++
> 6 files changed, 55 insertions(+), 3 deletions(-)
>
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 0796719..8808500 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -552,6 +552,10 @@ static QEMUMachine pc_i440fx_machine_v2_3 = {
> PC_I440FX_2_3_MACHINE_OPTIONS,
> .name = "pc-i440fx-2.3",
> .init = pc_init_pci_2_3,
> + .compat_props = (GlobalProperty[]) {
> + HW_COMPAT_2_3,
> + { /* end of list */ }
> + },
> };
>
> #define PC_I440FX_2_2_MACHINE_OPTIONS PC_I440FX_2_3_MACHINE_OPTIONS
> @@ -560,6 +564,10 @@ static QEMUMachine pc_i440fx_machine_v2_2 = {
> PC_I440FX_2_2_MACHINE_OPTIONS,
> .name = "pc-i440fx-2.2",
> .init = pc_init_pci_2_2,
> + .compat_props = (GlobalProperty[]) {
> + HW_COMPAT_2_2,
> + { /* end of list */ }
> + },
> };
>
> #define PC_I440FX_2_1_MACHINE_OPTIONS \
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index a8a34a4..4a34349 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -448,6 +448,10 @@ static QEMUMachine pc_q35_machine_v2_3 = {
> PC_Q35_2_3_MACHINE_OPTIONS,
> .name = "pc-q35-2.3",
> .init = pc_q35_init_2_3,
> + .compat_props = (GlobalProperty[]) {
> + HW_COMPAT_2_3,
> + { /* end of list */ }
> + },
> };
>
> #define PC_Q35_2_2_MACHINE_OPTIONS PC_Q35_2_3_MACHINE_OPTIONS
> @@ -456,6 +460,10 @@ static QEMUMachine pc_q35_machine_v2_2 = {
> PC_Q35_2_2_MACHINE_OPTIONS,
> .name = "pc-q35-2.2",
> .init = pc_q35_init_2_2,
> + .compat_props = (GlobalProperty[]) {
> + HW_COMPAT_2_2,
> + { /* end of list */ }
> + },
> };
>
> #define PC_Q35_2_1_MACHINE_OPTIONS \
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 5f25dd3..853a5cc 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1794,12 +1794,16 @@ static const TypeInfo spapr_machine_info = {
> },
> };
>
> +#define SPAPR_COMPAT_2_3 \
> + HW_COMPAT_2_3
> +
> #define SPAPR_COMPAT_2_2 \
> + SPAPR_COMPAT_2_3, \
> {\
> .driver = TYPE_SPAPR_PCI_HOST_BRIDGE,\
> .property = "mem_win_size",\
> .value = "0x20000000",\
> - }
> + } \
>
> #define SPAPR_COMPAT_2_1 \
> SPAPR_COMPAT_2_2
> @@ -1883,10 +1887,15 @@ static const TypeInfo spapr_machine_2_2_info = {
>
> static void spapr_machine_2_3_class_init(ObjectClass *oc, void *data)
> {
> + static GlobalProperty compat_props[] = {
> + SPAPR_COMPAT_2_3,
> + { /* end of list */ }
> + };
> MachineClass *mc = MACHINE_CLASS(oc);
>
> mc->name = "pseries-2.3";
> mc->desc = "pSeries Logical Partition (PAPR compliant) v2.3";
> + mc->compat_props = compat_props;
> }
>
> static const TypeInfo spapr_machine_2_3_info = {
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 4a5febb..f4cd405 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -925,7 +925,7 @@ static void virtio_pci_device_plugged(DeviceState *d)
> VirtIOPCIProxy *proxy = VIRTIO_PCI(d);
> VirtioBusState *bus = &proxy->bus;
> uint8_t *config;
> - uint32_t size;
> + uint32_t size, bar_size;
>
> config = proxy->pci_dev.config;
> if (proxy->class_code) {
> @@ -936,8 +936,19 @@ static void virtio_pci_device_plugged(DeviceState *d)
> pci_set_word(config + PCI_SUBSYSTEM_ID, virtio_bus_get_vdev_id(bus));
> config[PCI_INTERRUPT_PIN] = 1;
>
> + if (proxy->flags & VIRTIO_PCI_FLAG_AUTO_MSIX_SIZE) {
> + bar_size = proxy->nvectors * PCI_MSIX_ENTRY_SIZE * 2;
> + if (bar_size & (bar_size - 1)) {
> + bar_size = 1 << qemu_fls(bar_size);
> + }
> + } else {
> + /* For migration compatibility */
> + bar_size = 4096;
> + }
> +
> if (proxy->nvectors &&
> - msix_init_exclusive_bar(&proxy->pci_dev, proxy->nvectors, 1, 4096)) {
> + msix_init_exclusive_bar(&proxy->pci_dev, proxy->nvectors, 1,
> + bar_size)) {
> error_report("unable to init msix vectors to %" PRIu32,
> proxy->nvectors);
> proxy->nvectors = 0;
As I expected, msix format stuff spreads out to virtio.
Consider "vectors * PCI_MSIX_ENTRY_SIZE * 2"
That's because you use half the BAR for BIR in msix.c
So any change will have to be done in two places,
that's bad.
> @@ -1370,6 +1381,8 @@ static const TypeInfo virtio_serial_pci_info = {
> static Property virtio_net_properties[] = {
> DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags,
> VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, false),
> + DEFINE_PROP_BIT("auto_msix_bar_size", VirtIOPCIProxy, flags,
> + VIRTIO_PCI_FLAG_AUTO_MSIX_SIZE_BIT, true),
> DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 3),
> DEFINE_VIRTIO_NET_FEATURES(VirtIOPCIProxy, host_features),
> DEFINE_PROP_END_OF_LIST(),
> diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
> index 3bac016..82a6782 100644
> --- a/hw/virtio/virtio-pci.h
> +++ b/hw/virtio/virtio-pci.h
> @@ -62,6 +62,9 @@ typedef struct VirtioBusClass VirtioPCIBusClass;
> * vcpu thread using ioeventfd for some devices. */
> #define VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT 1
> #define VIRTIO_PCI_FLAG_USE_IOEVENTFD (1 <<
> VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT)
> +#define VIRTIO_PCI_FLAG_AUTO_MSIX_SIZE_BIT 2
> +#define VIRTIO_PCI_FLAG_AUTO_MSIX_SIZE \
> + (1 << VIRTIO_PCI_FLAG_AUTO_MSIX_SIZE_BIT)
>
> typedef struct {
> MSIMessage msg;
> diff --git a/include/hw/compat.h b/include/hw/compat.h
> index 313682a..3186275 100644
> --- a/include/hw/compat.h
> +++ b/include/hw/compat.h
> @@ -1,7 +1,18 @@
> #ifndef HW_COMPAT_H
> #define HW_COMPAT_H
>
> +#define HW_COMPAT_2_3 \
> + {\
> + .driver = "virtio-net-pci",\
> + .property = "auto_msix_bar_size",\
> + .value = "off",\
> + }
> +
> +#define HW_COMPAT_2_2 \
> + HW_COMPAT_2_3
> +
> #define HW_COMPAT_2_1 \
> + HW_COMPAT_2_2, \
> {\
> .driver = "intel-hda",\
> .property = "old_msi_addr",\
> --
> 2.1.0
- [Qemu-devel] [PATCH V4 14/19] virtio: introduce vector to virtqueues mapping, (continued)
- [Qemu-devel] [PATCH V4 14/19] virtio: introduce vector to virtqueues mapping, Jason Wang, 2015/03/18
- [Qemu-devel] [PATCH V4 16/19] virtio-pci: speedup MSI-X masking and unmasking, Jason Wang, 2015/03/18
- [Qemu-devel] [PATCH V4 15/19] virtio: introduce virtio_queue_get_index(), Jason Wang, 2015/03/18
- [Qemu-devel] [PATCH V4 17/19] virtio-pci: increase the maximum number of virtqueues to 513, Jason Wang, 2015/03/18
- [Qemu-devel] [PATCH V4 18/19] pci: remove hard-coded bar size in msix_init_exclusive_bar(), Jason Wang, 2015/03/18
[Qemu-devel] [PATCH V4 19/19] virtio-pci: introduce auto_msix_bar_size property, Jason Wang, 2015/03/18
- Re: [Qemu-devel] [PATCH V4 19/19] virtio-pci: introduce auto_msix_bar_size property,
Michael S. Tsirkin <=
Re: [Qemu-devel] [PATCH V4 19/19] virtio-pci: introduce auto_msix_bar_size property, Jason Wang, 2015/03/19
Re: [Qemu-devel] [PATCH V4 19/19] virtio-pci: introduce auto_msix_bar_size property, Michael S. Tsirkin, 2015/03/19
Re: [Qemu-devel] [PATCH V4 19/19] virtio-pci: introduce auto_msix_bar_size property, Jason Wang, 2015/03/20
Re: [Qemu-devel] [PATCH V4 00/19] Support more virtio queues, Michael S. Tsirkin, 2015/03/18