On Tue, Jan 20, 2015 at 06:12:11PM +0000, Pawel Moll wrote:
> This patch add a support for second version of the virtio-mmio device,
> which follows OASIS "Virtual I/O Device (VIRTIO) Version 1.0"
> specification.
>
> Main changes:
>
> 1. The control register symbolic names use the new device/driver
> nomenclature rather than the old guest/host one.
>
> 2. The driver detect the device version (version 1 is the pre-OASIS
> spec, version 2 is compatible with fist revision of the OASIS spec)
> and drives the device accordingly.
>
> 3. New version uses direct addressing (64 bit address split into two
> low/high register) instead of the guest page size based one,
> and addresses each part of the queue (descriptors, available, used)
> separately.
>
> 4. The device activity is now explicitly triggered by writing to the
> "queue ready" register.
>
> 5. Whole 64 bit features are properly handled now (both ways).
>
> Signed-off-by: Pawel Moll <pawel.moll@xxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
> drivers/virtio/virtio_mmio.c | 131 ++++++++++++++++++++++++++-----------------
> include/linux/virtio_mmio.h | 44 ++++++++++++---
> 2 files changed, 118 insertions(+), 57 deletions(-)
>
> Tested with our custom models (*not* qemu).
>
> Changes from v1:
>
> * added legacy/modern checks in probe and finalize_features.
>
> Changes from RFC:
>
> * removed the "version" sysfs attribute at its usablity was questioned
> * added #ifndefs allowing to disable legacy register names in the header
> * started using handy virtqueue_get_used/avail() functions instead of
> doing all the calculations manually
> * ID 0 special handled by returning -ENODEV instead of 0 - still prints
> no error (unless you've got DEBUG for drivers/base), but doesn't
> actually bind the device
>
> diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> index 00d115b..cad5698 100644
> --- a/drivers/virtio/virtio_mmio.c
> +++ b/drivers/virtio/virtio_mmio.c
> @@ -1,7 +1,7 @@
> /*
> * Virtio memory mapped device driver
> *
> - * Copyright 2011, ARM Ltd.
> + * Copyright 2011-2014, ARM Ltd.
> *
> * This module allows virtio devices to be used over a virtual, memory mapped
> * platform device.
> @@ -50,36 +50,6 @@
> *
> *
> *
> - * Registers layout (all 32-bit wide):
> - *
> - * offset d. name description
> - * ------ -- ---------------- -----------------
> - *
> - * 0x000 R MagicValue Magic value "virt"
> - * 0x004 R Version Device version (current max. 1)
> - * 0x008 R DeviceID Virtio device ID
> - * 0x00c R VendorID Virtio vendor ID
> - *
> - * 0x010 R HostFeatures Features supported by the host
> - * 0x014 W HostFeaturesSel Set of host features to access via HostFeatures
> - *
> - * 0x020 W GuestFeatures Features activated by the guest
> - * 0x024 W GuestFeaturesSel Set of activated features to set via GuestFeatures
> - * 0x028 W GuestPageSize Size of guest's memory page in bytes
> - *
> - * 0x030 W QueueSel Queue selector
> - * 0x034 R QueueNumMax Maximum size of the currently selected queue
> - * 0x038 W QueueNum Queue size for the currently selected queue
> - * 0x03c W QueueAlign Used Ring alignment for the current queue
> - * 0x040 RW QueuePFN PFN for the currently selected queue
> - *
> - * 0x050 W QueueNotify Queue notifier
> - * 0x060 R InterruptStatus Interrupt status register
> - * 0x064 W InterruptACK Interrupt acknowledge register
> - * 0x070 RW Status Device status register
> - *
> - * 0x100+ RW Device-specific configuration space
> - *
> * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
> *
> * This work is licensed under the terms of the GNU GPL, version 2 or later.
> @@ -145,11 +115,16 @@ struct virtio_mmio_vq_info {
> static u64 vm_get_features(struct virtio_device *vdev)
> {
> struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
> + u64 features;
> +
> + writel(1, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
> + features = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
> + features <<= 32;
>
> - /* TODO: Features > 32 bits */
> - writel(0, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL);
> + writel(0, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
> + features |= readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
>
> - return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
> + return features;
> }
>
> static int vm_finalize_features(struct virtio_device *vdev)
> @@ -159,11 +134,20 @@ static int vm_finalize_features(struct virtio_device *vdev)
> /* Give virtio_ring a chance to accept features. */
> vring_transport_features(vdev);
>
> - /* Make sure we don't have any features > 32 bits! */
> - BUG_ON((u32)vdev->features != vdev->features);
> + /* Make sure there is are no mixed devices */
> + if (vm_dev->version == 2 &&
> + !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
> + dev_err(&vdev->dev, "New virtio-mmio devices (version 2) must provide VIRTIO_F_VERSION_1 feature!\n");
> + return -EINVAL;
> + }
> +
> + writel(1, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
> + writel((u32)(vdev->features >> 32),
> + vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
>
> - writel(0, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
> - writel(vdev->features, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
> + writel(0, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
> + writel((u32)vdev->features,
> + vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
>
> return 0;
> }
> @@ -275,7 +259,12 @@ static void vm_del_vq(struct virtqueue *vq)
>
> /* Select and deactivate the queue */
> writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
> - writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
> + if (vm_dev->version == 1) {
> + writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
> + } else {
> + writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
> + WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
> + }
>
> size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
> free_pages_exact(info->queue, size);
> @@ -312,7 +301,8 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
> writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
>
> /* Queue shouldn't already be set up. */
> - if (readl(vm_dev->base + VIRTIO_MMIO_QUEUE_PFN)) {
> + if (readl(vm_dev->base + (vm_dev->version == 1 ?
> + VIRTIO_MMIO_QUEUE_PFN : VIRTIO_MMIO_QUEUE_READY))) {
> err = -ENOENT;
> goto error_available;
> }
> @@ -356,13 +346,6 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
> info->num /= 2;
> }
>
> - /* Activate the queue */
> - writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
> - writel(VIRTIO_MMIO_VRING_ALIGN,
> - vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
> - writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
> - vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
> -
> /* Create the vring */
> vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
> true, info->queue, vm_notify, callback, name);
> @@ -371,6 +354,33 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
> goto error_new_virtqueue;
> }
>
> + /* Activate the queue */
> + writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
> + if (vm_dev->version == 1) {
> + writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
> + writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
> + vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
> + } else {
> + u64 addr;
> +
> + addr = virt_to_phys(info->queue);
> + writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_LOW);
> + writel((u32)(addr >> 32),
> + vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_HIGH);
> +
> + addr = virt_to_phys(virtqueue_get_avail(vq));
> + writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_LOW);
> + writel((u32)(addr >> 32),
> + vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_HIGH);
> +
> + addr = virt_to_phys(virtqueue_get_used(vq));
> + writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_USED_LOW);
> + writel((u32)(addr >> 32),
> + vm_dev->base + VIRTIO_MMIO_QUEUE_USED_HIGH);
> +
> + writel(1, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
> + }
> +
> vq->priv = info;
> info->vq = vq;
>
> @@ -381,7 +391,12 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
> return vq;
>
> error_new_virtqueue:
> - writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
> + if (vm_dev->version == 1) {
> + writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
> + } else {
> + writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
> + WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
> + }
> free_pages_exact(info->queue, size);
> error_alloc_pages:
> kfree(info);
> @@ -476,16 +491,32 @@ static int virtio_mmio_probe(struct platform_device *pdev)
>
> /* Check device version */
> vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
> - if (vm_dev->version != 1) {
> + if (vm_dev->version < 1 || vm_dev->version > 2) {
> dev_err(&pdev->dev, "Version %ld not supported!\n",
> vm_dev->version);
> return -ENXIO;
> }
>
> vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
> + if (vm_dev->vdev.id.device == 0) {
> + /*
> + * virtio-mmio device with an ID 0 is a (dummy) placeholder
> + * with no function. End probing now with no error reported.
> + */
> + return -ENODEV;
> + }
> vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
>
> - writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
> + /* Reject legacy-only IDs for version 2 devices */
> + if (vm_dev->version == 2 &&
> + virtio_device_is_legacy_only(vm_dev->vdev.id)) {
> + dev_err(&pdev->dev, "Version 2 not supported for devices %u!\n",
> + vm_dev->vdev.id.device);
> + return -ENODEV;
> + }
> +
> + if (vm_dev->version == 1)
> + writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
>
> platform_set_drvdata(pdev, vm_dev);
>
> diff --git a/include/linux/virtio_mmio.h b/include/linux/virtio_mmio.h
> index 5c7b6f0..c4b0968 100644
> --- a/include/linux/virtio_mmio.h
> +++ b/include/linux/virtio_mmio.h
> @@ -51,23 +51,29 @@
> /* Virtio vendor ID - Read Only */
> #define VIRTIO_MMIO_VENDOR_ID 0x00c
>
> -/* Bitmask of the features supported by the host
> +/* Bitmask of the features supported by the device (host)
> * (32 bits per set) - Read Only */
> -#define VIRTIO_MMIO_HOST_FEATURES 0x010
> +#define VIRTIO_MMIO_DEVICE_FEATURES 0x010
>
> -/* Host features set selector - Write Only */
> -#define VIRTIO_MMIO_HOST_FEATURES_SEL 0x014
> +/* Device (host) features set selector - Write Only */
> +#define VIRTIO_MMIO_DEVICE_FEATURES_SEL 0x014
>
> -/* Bitmask of features activated by the guest
> +/* Bitmask of features activated by the driver (guest)
> * (32 bits per set) - Write Only */
> -#define VIRTIO_MMIO_GUEST_FEATURES 0x020
> +#define VIRTIO_MMIO_DRIVER_FEATURES 0x020
>
> /* Activated features set selector - Write Only */
> -#define VIRTIO_MMIO_GUEST_FEATURES_SEL 0x024
> +#define VIRTIO_MMIO_DRIVER_FEATURES_SEL 0x024
> +
> +
> +#ifndef VIRTIO_MMIO_NO_LEGACY /* LEGACY DEVICES ONLY! */
>
> /* Guest's memory page size in bytes - Write Only */
> #define VIRTIO_MMIO_GUEST_PAGE_SIZE 0x028
>
> +#endif
> +
> +
> /* Queue selector - Write Only */
> #define VIRTIO_MMIO_QUEUE_SEL 0x030
>
> @@ -77,12 +83,21 @@
> /* Queue size for the currently selected queue - Write Only */
> #define VIRTIO_MMIO_QUEUE_NUM 0x038
>
> +
> +#ifndef VIRTIO_MMIO_NO_LEGACY /* LEGACY DEVICES ONLY! */
> +
> /* Used Ring alignment for the currently selected queue - Write Only */
> #define VIRTIO_MMIO_QUEUE_ALIGN 0x03c
>
> /* Guest's PFN for the currently selected queue - Read Write */
> #define VIRTIO_MMIO_QUEUE_PFN 0x040
>
> +#endif
> +
> +
> +/* Ready bit for the currently selected queue - Read Write */
> +#define VIRTIO_MMIO_QUEUE_READY 0x044
> +
> /* Queue notifier - Write Only */
> #define VIRTIO_MMIO_QUEUE_NOTIFY 0x050
>
> @@ -95,6 +110,21 @@
> /* Device status register - Read Write */
> #define VIRTIO_MMIO_STATUS 0x070
>
> +/* Selected queue's Descriptor Table address, 64 bits in two halves */
> +#define VIRTIO_MMIO_QUEUE_DESC_LOW 0x080
> +#define VIRTIO_MMIO_QUEUE_DESC_HIGH 0x084
> +
> +/* Selected queue's Available Ring address, 64 bits in two halves */
> +#define VIRTIO_MMIO_QUEUE_AVAIL_LOW 0x090
> +#define VIRTIO_MMIO_QUEUE_AVAIL_HIGH 0x094
> +
> +/* Selected queue's Used Ring address, 64 bits in two halves */
> +#define VIRTIO_MMIO_QUEUE_USED_LOW 0x0a0
> +#define VIRTIO_MMIO_QUEUE_USED_HIGH 0x0a4
> +
> +/* Configuration atomicity value */
> +#define VIRTIO_MMIO_CONFIG_GENERATION 0x0fc
> +
> /* The config space is defined by each driver as
> * the per-driver configuration space - Read Write */
> #define VIRTIO_MMIO_CONFIG 0x100
> --
> 2.1.0
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