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Re: [Qemu-devel] [PATCH 5/6] virtio-pci: introduce pio notification capa
From: |
Greg Kurz |
Subject: |
Re: [Qemu-devel] [PATCH 5/6] virtio-pci: introduce pio notification capability for modern device |
Date: |
Mon, 24 Aug 2015 16:52:45 +0200 |
On Fri, 21 Aug 2015 17:05:49 +0800
Jason Wang <address@hidden> wrote:
> We used to use mmio for notification. This could be slow on some arch
> (e.g on x86 without EPT). So this patch introduces pio bar and a pio
> notification cap for modern device. This ability is enabled through
> property "modern-pio-notify" for virtio pci devices and was disabled
> by default. Management can enable when it thinks it was needed.
>
> Benchmarks shows almost no obvious difference with legacy device.
> Thanks Wenli Quan <address@hidden> for the benchmarking.
>
> Cc: Michael S. Tsirkin <address@hidden>
> Signed-off-by: Jason Wang <address@hidden>
> ---
> hw/virtio/virtio-pci.c | 122
> ++++++++++++++++++++++++++++++++++++++++++-------
> hw/virtio/virtio-pci.h | 10 ++++
> 2 files changed, 115 insertions(+), 17 deletions(-)
>
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index fbd1f1f..e399565 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -210,7 +210,9 @@ static int
> virtio_pci_set_host_notifier_internal(VirtIOPCIProxy *proxy,
> EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
> bool legacy = !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_LEGACY);
> bool modern = !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_MODERN);
> + bool modern_pio = proxy->flags & VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY;
> MemoryRegion *modern_mr = &proxy->notify.mr;
> + MemoryRegion *modern_notify_mr = &proxy->notify_pio.mr;
> MemoryRegion *legacy_mr = &proxy->bar;
> hwaddr modern_addr = QEMU_VIRTIO_PCI_QUEUE_MEM_MULT *
> virtio_get_queue_index(vq);
> @@ -228,6 +230,10 @@ static int
> virtio_pci_set_host_notifier_internal(VirtIOPCIProxy *proxy,
> if (modern) {
> memory_region_add_eventfd(modern_mr, modern_addr, 0,
> false, n, notifier);
> + if (modern_pio) {
> + memory_region_add_eventfd(modern_notify_mr, 0, 2,
> + true, n, notifier);
> + }
This calls for the following change in memory.c:
static void adjust_endianness(MemoryRegion *mr, uint64_t *data, unsigned size)
{
- if (memory_region_wrong_endianness(mr)) {
+ if (size && memory_region_wrong_endianness(mr)) {
otherwise we abort on PPC64.
> }
> if (legacy) {
> memory_region_add_eventfd(legacy_mr, legacy_addr, 2,
> @@ -237,6 +243,10 @@ static int
> virtio_pci_set_host_notifier_internal(VirtIOPCIProxy *proxy,
> if (modern) {
> memory_region_del_eventfd(modern_mr, modern_addr, 0,
> false, n, notifier);
> + if (modern_pio) {
> + memory_region_del_eventfd(modern_notify_mr, 0, 2,
> + true, n, notifier);
> + }
> }
> if (legacy) {
> memory_region_del_eventfd(legacy_mr, legacy_addr, 2,
> @@ -1344,6 +1354,17 @@ static void virtio_pci_notify_write(void *opaque,
> hwaddr addr,
> }
> }
>
> +static void virtio_pci_notify_write_pio(void *opaque, hwaddr addr,
> + uint64_t val, unsigned size)
> +{
> + VirtIODevice *vdev = opaque;
> + unsigned queue = val;
> +
> + if (queue < VIRTIO_QUEUE_MAX) {
> + virtio_queue_notify(vdev, queue);
> + }
> +}
> +
> static uint64_t virtio_pci_isr_read(void *opaque, hwaddr addr,
> unsigned size)
> {
> @@ -1437,6 +1458,16 @@ static void
> virtio_pci_modern_regions_init(VirtIOPCIProxy *proxy)
> },
> .endianness = DEVICE_LITTLE_ENDIAN,
> };
> + static const MemoryRegionOps notify_pio_ops = {
> + .read = virtio_pci_notify_read,
> + .write = virtio_pci_notify_write_pio,
> + .impl = {
> + .min_access_size = 1,
> + .max_access_size = 4,
> + },
> + .endianness = DEVICE_LITTLE_ENDIAN,
> + };
> +
>
> memory_region_init_io(&proxy->common.mr, OBJECT(proxy),
> &common_ops,
> @@ -1461,30 +1492,60 @@ static void
> virtio_pci_modern_regions_init(VirtIOPCIProxy *proxy)
> virtio_bus_get_device(&proxy->bus),
> "virtio-pci-notify",
> proxy->notify.size);
> +
> + memory_region_init_io(&proxy->notify_pio.mr, OBJECT(proxy),
> + ¬ify_pio_ops,
> + virtio_bus_get_device(&proxy->bus),
> + "virtio-pci-notify-pio",
> + proxy->notify.size);
> }
>
> static void virtio_pci_modern_region_map(VirtIOPCIProxy *proxy,
> VirtIOPCIRegion *region,
> - struct virtio_pci_cap *cap)
> + struct virtio_pci_cap *cap,
> + MemoryRegion *mr,
> + uint8_t bar)
> {
> - memory_region_add_subregion(&proxy->modern_bar,
> - region->offset,
> - ®ion->mr);
> + memory_region_add_subregion(mr, region->offset, ®ion->mr);
>
> cap->cfg_type = region->type;
> - cap->bar = proxy->modern_mem_bar;
> + cap->bar = bar;
> cap->offset = cpu_to_le32(region->offset);
> cap->length = cpu_to_le32(region->size);
> virtio_pci_add_mem_cap(proxy, cap);
> +
> +}
> +
> +static void virtio_pci_modern_mem_region_map(VirtIOPCIProxy *proxy,
> + VirtIOPCIRegion *region,
> + struct virtio_pci_cap *cap)
> +{
> + virtio_pci_modern_region_map(proxy, region, cap,
> + &proxy->modern_bar, proxy->modern_mem_bar);
> }
>
> -static void virtio_pci_modern_region_unmap(VirtIOPCIProxy *proxy,
> - VirtIOPCIRegion *region)
> +static void virtio_pci_modern_io_region_map(VirtIOPCIProxy *proxy,
> + VirtIOPCIRegion *region,
> + struct virtio_pci_cap *cap)
> +{
> + virtio_pci_modern_region_map(proxy, region, cap,
> + &proxy->io_bar, proxy->modern_io_bar);
> +}
> +
> +static void virtio_pci_modern_mem_region_unmap(VirtIOPCIProxy *proxy,
> + VirtIOPCIRegion *region)
> {
> memory_region_del_subregion(&proxy->modern_bar,
> ®ion->mr);
> }
>
> +static void virtio_pci_modern_io_region_unmap(VirtIOPCIProxy *proxy,
> + VirtIOPCIRegion *region)
> +{
> + memory_region_del_subregion(&proxy->io_bar,
> + ®ion->mr);
> +}
> +
> /* This is called by virtio-bus just after the device is plugged. */
> static void virtio_pci_device_plugged(DeviceState *d, Error **errp)
> {
> @@ -1492,6 +1553,7 @@ static void virtio_pci_device_plugged(DeviceState *d,
> Error **errp)
> VirtioBusState *bus = &proxy->bus;
> bool legacy = !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_LEGACY);
> bool modern = !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_MODERN);
> + bool modern_pio = proxy->flags & VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY;
> uint8_t *config;
> uint32_t size;
> VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> @@ -1530,16 +1592,31 @@ static void virtio_pci_device_plugged(DeviceState *d,
> Error **errp)
> .cap.cap_len = sizeof cfg,
> .cap.cfg_type = VIRTIO_PCI_CAP_PCI_CFG,
> };
> - struct virtio_pci_cfg_cap *cfg_mask;
> + struct virtio_pci_notify_cap notify_pio = {
> + .cap.cap_len = sizeof notify,
> + .notify_off_multiplier = cpu_to_le32(0x0),
> + };
>
> - /* TODO: add io access for speed */
> + struct virtio_pci_cfg_cap *cfg_mask;
>
> virtio_add_feature(&vdev->host_features, VIRTIO_F_VERSION_1);
> virtio_pci_modern_regions_init(proxy);
> - virtio_pci_modern_region_map(proxy, &proxy->common, &cap);
> - virtio_pci_modern_region_map(proxy, &proxy->isr, &cap);
> - virtio_pci_modern_region_map(proxy, &proxy->device, &cap);
> - virtio_pci_modern_region_map(proxy, &proxy->notify, ¬ify.cap);
> +
> + virtio_pci_modern_mem_region_map(proxy, &proxy->common, &cap);
> + virtio_pci_modern_mem_region_map(proxy, &proxy->isr, &cap);
> + virtio_pci_modern_mem_region_map(proxy, &proxy->device, &cap);
> + virtio_pci_modern_mem_region_map(proxy, &proxy->notify, ¬ify.cap);
> +
> + if (modern_pio) {
> + memory_region_init(&proxy->io_bar, OBJECT(proxy),
> + "virtio-pci-io", 0x4);
> +
> + pci_register_bar(&proxy->pci_dev, proxy->modern_io_bar,
> + PCI_BASE_ADDRESS_SPACE_IO, &proxy->io_bar);
> +
> + virtio_pci_modern_io_region_map(proxy, &proxy->notify_pio,
> + ¬ify_pio.cap);
> + }
>
> pci_register_bar(&proxy->pci_dev, proxy->modern_mem_bar,
> PCI_BASE_ADDRESS_SPACE_MEMORY |
> @@ -1592,14 +1669,18 @@ static void virtio_pci_device_unplugged(DeviceState
> *d)
> {
> VirtIOPCIProxy *proxy = VIRTIO_PCI(d);
> bool modern = !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_MODERN);
> + bool modern_pio = proxy->flags & VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY;
>
> virtio_pci_stop_ioeventfd(proxy);
>
> if (modern) {
> - virtio_pci_modern_region_unmap(proxy, &proxy->common);
> - virtio_pci_modern_region_unmap(proxy, &proxy->isr);
> - virtio_pci_modern_region_unmap(proxy, &proxy->device);
> - virtio_pci_modern_region_unmap(proxy, &proxy->notify);
> + virtio_pci_modern_mem_region_unmap(proxy, &proxy->common);
> + virtio_pci_modern_mem_region_unmap(proxy, &proxy->isr);
> + virtio_pci_modern_mem_region_unmap(proxy, &proxy->device);
> + virtio_pci_modern_mem_region_unmap(proxy, &proxy->notify);
> + if (modern_pio) {
> + virtio_pci_modern_io_region_unmap(proxy, &proxy->notify_pio);
> + }
> }
> }
>
> @@ -1619,6 +1700,7 @@ static void virtio_pci_realize(PCIDevice *pci_dev,
> Error **errp)
> */
> proxy->legacy_io_bar = 0;
> proxy->msix_bar = 1;
> + proxy->modern_io_bar = 2;
> proxy->modern_mem_bar = 4;
>
> proxy->common.offset = 0x0;
> @@ -1638,6 +1720,10 @@ static void virtio_pci_realize(PCIDevice *pci_dev,
> Error **errp)
> QEMU_VIRTIO_PCI_QUEUE_MEM_MULT * VIRTIO_QUEUE_MAX;
> proxy->notify.type = VIRTIO_PCI_CAP_NOTIFY_CFG;
>
> + proxy->notify_pio.offset = 0x0;
> + proxy->notify_pio.size = 0x4;
> + proxy->notify_pio.type = VIRTIO_PCI_CAP_NOTIFY_CFG;
> +
> /* subclasses can enforce modern, so do this unconditionally */
> memory_region_init(&proxy->modern_bar, OBJECT(proxy), "virtio-pci",
> 2 * QEMU_VIRTIO_PCI_QUEUE_MEM_MULT *
> @@ -1684,6 +1770,8 @@ static Property virtio_pci_properties[] = {
> VIRTIO_PCI_FLAG_DISABLE_MODERN_BIT, true),
> DEFINE_PROP_BIT("migrate-modern", VirtIOPCIProxy, flags,
> VIRTIO_PCI_FLAG_MIGRATE_MODERN_BIT, true),
> + DEFINE_PROP_BIT("modern-pio-notify", VirtIOPCIProxy, flags,
> + VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY_BIT, false),
> DEFINE_PROP_END_OF_LIST(),
> };
>
> diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
> index fd2e889..491edfd 100644
> --- a/hw/virtio/virtio-pci.h
> +++ b/hw/virtio/virtio-pci.h
> @@ -79,6 +79,13 @@ typedef struct VirtioBusClass VirtioPCIBusClass;
> #define VIRTIO_PCI_FLAG_MIGRATE_MODERN_BIT 4
> #define VIRTIO_PCI_FLAG_MIGRATE_MODERN (1 <<
> VIRTIO_PCI_FLAG_MIGRATE_MODERN_BIT)
>
> +/* have pio notification for modern device ? */
> +#define VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY_BIT 5
> +#define VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY \
> + (1 << VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY_BIT)
> +
> +
> +
> typedef struct {
> MSIMessage msg;
> int virq;
> @@ -123,11 +130,14 @@ struct VirtIOPCIProxy {
> VirtIOPCIRegion isr;
> VirtIOPCIRegion device;
> VirtIOPCIRegion notify;
> + VirtIOPCIRegion notify_pio;
> MemoryRegion modern_bar;
> + MemoryRegion io_bar;
> MemoryRegion modern_cfg;
> AddressSpace modern_as;
> uint32_t legacy_io_bar;
> uint32_t msix_bar;
> + uint32_t modern_io_bar;
> uint32_t modern_mem_bar;
> int config_cap;
> uint32_t flags;
- Re: [Qemu-devel] [PATCH 2/6] ppc: spapr: introduce 2.5 machine type, (continued)
[Qemu-devel] [PATCH 4/6] virtio-pci: use wildcard mmio eventfd for 1.0 notification cap, Jason Wang, 2015/08/21
[Qemu-devel] [PATCH 5/6] virtio-pci: introduce pio notification capability for modern device, Jason Wang, 2015/08/21
[Qemu-devel] [PATCH 6/6] virtio-pci: unbreak queue_enable read, Jason Wang, 2015/08/21