On 25/02/14 18:24, Cornelia Huck wrote:
> Implement the new CCW_CMD_SET_IND_ADAPTER command and try to enable
> adapter interrupts for every device on the first startup. If the host
> does not support adapter interrupts, fall back to normal I/O interrupts.
>
> virtio-ccw adapter interrupts use the same isc as normal I/O subchannels
> and share a summary indicator for all devices sharing the same indicator
> area.
>
> Indicator bits for the individual virtqueues may be contained in the same
> indicator area for different devices.
>
> Signed-off-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
This is s390 only code, so I will queue that for my next KVM:s390 pull request
(I will also queue patch 1. It is also in s390/features, but patch 2
needs it).
For everything else (irqfd etc) I prefer to have some review from the
other platforms, since we change common code.
Christian
> ---
> arch/s390/include/asm/irq.h | 1 +
> arch/s390/kernel/irq.c | 1 +
> drivers/s390/kvm/virtio_ccw.c | 276 +++++++++++++++++++++++++++++++++++++++--
> 3 files changed, 268 insertions(+), 10 deletions(-)
>
> diff --git a/arch/s390/include/asm/irq.h b/arch/s390/include/asm/irq.h
> index 5f8bcc5..35f0faa 100644
> --- a/arch/s390/include/asm/irq.h
> +++ b/arch/s390/include/asm/irq.h
> @@ -53,6 +53,7 @@ enum interruption_class {
> IRQIO_PCI,
> IRQIO_MSI,
> IRQIO_VIR,
> + IRQIO_VAI,
> NMI_NMI,
> CPU_RST,
> NR_ARCH_IRQS
> diff --git a/arch/s390/kernel/irq.c b/arch/s390/kernel/irq.c
> index bb27a26..c288ef7 100644
> --- a/arch/s390/kernel/irq.c
> +++ b/arch/s390/kernel/irq.c
> @@ -84,6 +84,7 @@ static const struct irq_class irqclass_sub_desc[NR_ARCH_IRQS] = {
> [IRQIO_PCI] = {.name = "PCI", .desc = "[I/O] PCI Interrupt" },
> [IRQIO_MSI] = {.name = "MSI", .desc = "[I/O] MSI Interrupt" },
> [IRQIO_VIR] = {.name = "VIR", .desc = "[I/O] Virtual I/O Devices"},
> + [IRQIO_VAI] = {.name = "VAI", .desc = "[I/O] Virtual I/O Devices AI"},
> [NMI_NMI] = {.name = "NMI", .desc = "[NMI] Machine Check"},
> [CPU_RST] = {.name = "RST", .desc = "[CPU] CPU Restart"},
> };
> diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
> index 0fc5848..09afefe 100644
> --- a/drivers/s390/kvm/virtio_ccw.c
> +++ b/drivers/s390/kvm/virtio_ccw.c
> @@ -1,7 +1,7 @@
> /*
> * ccw based virtio transport
> *
> - * Copyright IBM Corp. 2012
> + * Copyright IBM Corp. 2012,2014
> *
> * This program is free software; you can redistribute it and/or modify
> * it under the terms of the GNU General Public License (version 2 only)
> @@ -32,6 +32,8 @@
> #include <asm/cio.h>
> #include <asm/ccwdev.h>
> #include <asm/virtio-ccw.h>
> +#include <asm/isc.h>
> +#include <asm/airq.h>
>
> /*
> * virtio related functions
> @@ -58,6 +60,8 @@ struct virtio_ccw_device {
> unsigned long indicators;
> unsigned long indicators2;
> struct vq_config_block *config_block;
> + bool is_thinint;
> + void *airq_info;
> };
>
> struct vq_info_block {
> @@ -72,15 +76,38 @@ struct virtio_feature_desc {
> __u8 index;
> } __packed;
>
> +struct virtio_thinint_area {
> + unsigned long summary_indicator;
> + unsigned long indicator;
> + u64 bit_nr;
> + u8 isc;
> +} __packed;
> +
> struct virtio_ccw_vq_info {
> struct virtqueue *vq;
> int num;
> void *queue;
> struct vq_info_block *info_block;
> + int bit_nr;
> struct list_head node;
> long cookie;
> };
>
> +#define VIRTIO_AIRQ_ISC IO_SCH_ISC /* inherit from subchannel */
> +
> +#define VIRTIO_IV_BITS (L1_CACHE_BYTES * 8)
> +#define MAX_AIRQ_AREAS 20
> +
> +static int virtio_ccw_use_airq = 1;
> +
> +struct airq_info {
> + rwlock_t lock;
> + u8 summary_indicator;
> + struct airq_struct airq;
> + struct airq_iv *aiv;
> +};
> +static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
> +
> #define CCW_CMD_SET_VQ 0x13
> #define CCW_CMD_VDEV_RESET 0x33
> #define CCW_CMD_SET_IND 0x43
> @@ -91,6 +118,7 @@ struct virtio_ccw_vq_info {
> #define CCW_CMD_WRITE_CONF 0x21
> #define CCW_CMD_WRITE_STATUS 0x31
> #define CCW_CMD_READ_VQ_CONF 0x32
> +#define CCW_CMD_SET_IND_ADAPTER 0x73
>
> #define VIRTIO_CCW_DOING_SET_VQ 0x00010000
> #define VIRTIO_CCW_DOING_RESET 0x00040000
> @@ -102,6 +130,7 @@ struct virtio_ccw_vq_info {
> #define VIRTIO_CCW_DOING_SET_IND 0x01000000
> #define VIRTIO_CCW_DOING_READ_VQ_CONF 0x02000000
> #define VIRTIO_CCW_DOING_SET_CONF_IND 0x04000000
> +#define VIRTIO_CCW_DOING_SET_IND_ADAPTER 0x08000000
> #define VIRTIO_CCW_INTPARM_MASK 0xffff0000
>
> static struct virtio_ccw_device *to_vc_device(struct virtio_device *vdev)
> @@ -109,6 +138,125 @@ static struct virtio_ccw_device *to_vc_device(struct virtio_device *vdev)
> return container_of(vdev, struct virtio_ccw_device, vdev);
> }
>
> +static void drop_airq_indicator(struct virtqueue *vq, struct airq_info *info)
> +{
> + unsigned long i, flags;
> +
> + write_lock_irqsave(&info->lock, flags);
> + for (i = 0; i < airq_iv_end(info->aiv); i++) {
> + if (vq == (void *)airq_iv_get_ptr(info->aiv, i)) {
> + airq_iv_free_bit(info->aiv, i);
> + airq_iv_set_ptr(info->aiv, i, 0);
> + break;
> + }
> + }
> + write_unlock_irqrestore(&info->lock, flags);
> +}
> +
> +static void virtio_airq_handler(struct airq_struct *airq)
> +{
> + struct airq_info *info = container_of(airq, struct airq_info, airq);
> + unsigned long ai;
> +
> + inc_irq_stat(IRQIO_VAI);
> + read_lock(&info->lock);
> + /* Walk through indicators field, summary indicator active. */
> + for (ai = 0;;) {
> + ai = airq_iv_scan(info->aiv, ai, airq_iv_end(info->aiv));
> + if (ai == -1UL)
> + break;
> + vring_interrupt(0, (void *)airq_iv_get_ptr(info->aiv, ai));
> + }
> + info->summary_indicator = 0;
> + smp_wmb();
> + /* Walk through indicators field, summary indicator not active. */
> + for (ai = 0;;) {
> + ai = airq_iv_scan(info->aiv, ai, airq_iv_end(info->aiv));
> + if (ai == -1UL)
> + break;
> + vring_interrupt(0, (void *)airq_iv_get_ptr(info->aiv, ai));
> + }
> + read_unlock(&info->lock);
> +}
> +
> +static struct airq_info *new_airq_info(void)
> +{
> + struct airq_info *info;
> + int rc;
> +
> + info = kzalloc(sizeof(*info), GFP_KERNEL);
> + if (!info)
> + return NULL;
> + rwlock_init(&info->lock);
> + info->aiv = airq_iv_create(VIRTIO_IV_BITS, AIRQ_IV_ALLOC | AIRQ_IV_PTR);
> + if (!info->aiv) {
> + kfree(info);
> + return NULL;
> + }
> + info->airq.handler = virtio_airq_handler;
> + info->airq.lsi_ptr = &info->summary_indicator;
> + info->airq.lsi_mask = 0xff;
> + info->airq.isc = VIRTIO_AIRQ_ISC;
> + rc = register_adapter_interrupt(&info->airq);
> + if (rc) {
> + airq_iv_release(info->aiv);
> + kfree(info);
> + return NULL;
> + }
> + return info;
> +}
> +
> +static void destroy_airq_info(struct airq_info *info)
> +{
> + if (!info)
> + return;
> +
> + unregister_adapter_interrupt(&info->airq);
> + airq_iv_release(info->aiv);
> + kfree(info);
> +}
> +
> +static unsigned long get_airq_indicator(struct virtqueue *vqs[], int nvqs,
> + u64 *first, void **airq_info)
> +{
> + int i, j;
> + struct airq_info *info;
> + unsigned long indicator_addr = 0;
> + unsigned long bit, flags;
> +
> + for (i = 0; i < MAX_AIRQ_AREAS && !indicator_addr; i++) {
> + if (!airq_areas[i])
> + airq_areas[i] = new_airq_info();
> + info = airq_areas[i];
> + if (!info)
> + return 0;
> + write_lock_irqsave(&info->lock, flags);
> + bit = airq_iv_alloc(info->aiv, nvqs);
> + if (bit == -1UL) {
> + /* Not enough vacancies. */
> + write_unlock_irqrestore(&info->lock, flags);
> + continue;
> + }
> + *first = bit;
> + *airq_info = info;
> + indicator_addr = (unsigned long)info->aiv->vector;
> + for (j = 0; j < nvqs; j++) {
> + airq_iv_set_ptr(info->aiv, bit + j,
> + (unsigned long)vqs[j]);
> + }
> + write_unlock_irqrestore(&info->lock, flags);
> + }
> + return indicator_addr;
> +}
> +
> +static void virtio_ccw_drop_indicators(struct virtio_ccw_device *vcdev)
> +{
> + struct virtio_ccw_vq_info *info;
> +
> + list_for_each_entry(info, &vcdev->virtqueues, node)
> + drop_airq_indicator(info->vq, vcdev->airq_info);
> +}
> +
> static int doing_io(struct virtio_ccw_device *vcdev, __u32 flag)
> {
> unsigned long flags;
> @@ -145,6 +293,51 @@ static int ccw_io_helper(struct virtio_ccw_device *vcdev,
> return ret ? ret : vcdev->err;
> }
>
> +static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
> + struct ccw1 *ccw)
> +{
> + int ret;
> + unsigned long *indicatorp = NULL;
> + struct virtio_thinint_area *thinint_area = NULL;
> + struct airq_info *airq_info = vcdev->airq_info;
> +
> + if (vcdev->is_thinint) {
> + thinint_area = kzalloc(sizeof(*thinint_area),
> + GFP_DMA | GFP_KERNEL);
> + if (!thinint_area)
> + return;
> + thinint_area->summary_indicator =
> + (unsigned long) &airq_info->summary_indicator;
> + thinint_area->isc = VIRTIO_AIRQ_ISC;
> + ccw->cmd_code = CCW_CMD_SET_IND_ADAPTER;
> + ccw->count = sizeof(*thinint_area);
> + ccw->cda = (__u32)(unsigned long) thinint_area;
> + } else {
> + indicatorp = kmalloc(sizeof(&vcdev->indicators),
> + GFP_DMA | GFP_KERNEL);
> + if (!indicatorp)
> + return;
> + *indicatorp = 0;
> + ccw->cmd_code = CCW_CMD_SET_IND;
> + ccw->count = sizeof(vcdev->indicators);
> + ccw->cda = (__u32)(unsigned long) indicatorp;
> + }
> + /* Deregister indicators from host. */
> + vcdev->indicators = 0;
> + ccw->flags = 0;
> + ret = ccw_io_helper(vcdev, ccw,
> + vcdev->is_thinint ?
> + VIRTIO_CCW_DOING_SET_IND_ADAPTER :
> + VIRTIO_CCW_DOING_SET_IND);
> + if (ret && (ret != -ENODEV))
> + dev_info(&vcdev->cdev->dev,
> + "Failed to deregister indicators (%d)\n", ret);
> + else if (vcdev->is_thinint)
> + virtio_ccw_drop_indicators(vcdev);
> + kfree(indicatorp);
> + kfree(thinint_area);
> +}
> +
> static inline long do_kvm_notify(struct subchannel_id schid,
> unsigned long queue_index,
> long cookie)
> @@ -232,11 +425,13 @@ static void virtio_ccw_del_vqs(struct virtio_device *vdev)
> {
> struct virtqueue *vq, *n;
> struct ccw1 *ccw;
> + struct virtio_ccw_device *vcdev = to_vc_device(vdev);
>
> ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
> if (!ccw)
> return;
>
> + virtio_ccw_drop_indicator(vcdev, ccw);
>
> list_for_each_entry_safe(vq, n, &vdev->vqs, list)
> virtio_ccw_del_vq(vq, ccw);
> @@ -326,6 +521,52 @@ out_err:
> return ERR_PTR(err);
> }
>
> +static int virtio_ccw_register_adapter_ind(struct virtio_ccw_device *vcdev,
> + struct virtqueue *vqs[], int nvqs,
> + struct ccw1 *ccw)
> +{
> + int ret;
> + struct virtio_thinint_area *thinint_area = NULL;
> + struct airq_info *info;
> +
> + thinint_area = kzalloc(sizeof(*thinint_area), GFP_DMA | GFP_KERNEL);
> + if (!thinint_area) {
> + ret = -ENOMEM;
> + goto out;
> + }
> + /* Try to get an indicator. */
> + thinint_area->indicator = get_airq_indicator(vqs, nvqs,
> + &thinint_area->bit_nr,
> + &vcdev->airq_info);
> + if (!thinint_area->indicator) {
> + ret = -ENOSPC;
> + goto out;
> + }
> + info = vcdev->airq_info;
> + thinint_area->summary_indicator =
> + (unsigned long) &info->summary_indicator;
> + thinint_area->isc = VIRTIO_AIRQ_ISC;
> + ccw->cmd_code = CCW_CMD_SET_IND_ADAPTER;
> + ccw->flags = CCW_FLAG_SLI;
> + ccw->count = sizeof(*thinint_area);
> + ccw->cda = (__u32)(unsigned long)thinint_area;
> + ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_IND_ADAPTER);
> + if (ret) {
> + dev_warn(&vcdev->cdev->dev,
> + "enabling adapter interrupts = %d\n", ret);
> + if (ret == -EOPNOTSUPP)
> + /*
> + * The host does not support adapter interrupts
> + * for virtio-ccw, stop trying.
> + */
> + virtio_ccw_use_airq = 0;
> + virtio_ccw_drop_indicators(vcdev);
> + }
> +out:
> + kfree(thinint_area);
> + return ret;
> +}
> +
> static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
> struct virtqueue *vqs[],
> vq_callback_t *callbacks[],
> @@ -355,15 +596,23 @@ static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
> if (!indicatorp)
> goto out;
> *indicatorp = (unsigned long) &vcdev->indicators;
> - /* Register queue indicators with host. */
> - vcdev->indicators = 0;
> - ccw->cmd_code = CCW_CMD_SET_IND;
> - ccw->flags = 0;
> - ccw->count = sizeof(vcdev->indicators);
> - ccw->cda = (__u32)(unsigned long) indicatorp;
> - ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_IND);
> - if (ret)
> - goto out;
> + if (vcdev->is_thinint) {
> + ret = virtio_ccw_register_adapter_ind(vcdev, vqs, nvqs, ccw);
> + if (ret)
> + /* no error, just fall back to legacy interrupts */
> + vcdev->is_thinint = 0;
> + }
> + if (!vcdev->is_thinint) {
> + /* Register queue indicators with host. */
> + vcdev->indicators = 0;
> + ccw->cmd_code = CCW_CMD_SET_IND;
> + ccw->flags = 0;
> + ccw->count = sizeof(vcdev->indicators);
> + ccw->cda = (__u32)(unsigned long) indicatorp;
> + ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_IND);
> + if (ret)
> + goto out;
> + }
> /* Register indicators2 with host for config changes */
> *indicatorp = (unsigned long) &vcdev->indicators2;
> vcdev->indicators2 = 0;
> @@ -663,6 +912,7 @@ static void virtio_ccw_int_handler(struct ccw_device *cdev,
> case VIRTIO_CCW_DOING_SET_CONF_IND:
> case VIRTIO_CCW_DOING_RESET:
> case VIRTIO_CCW_DOING_READ_VQ_CONF:
> + case VIRTIO_CCW_DOING_SET_IND_ADAPTER:
> vcdev->curr_io &= ~activity;
> wake_up(&vcdev->wait_q);
> break;
> @@ -778,6 +1028,8 @@ static int virtio_ccw_online(struct ccw_device *cdev)
> goto out_free;
> }
>
> + vcdev->is_thinint = virtio_ccw_use_airq; /* at least try */
> +
> vcdev->vdev.dev.parent = &cdev->dev;
> vcdev->vdev.dev.release = virtio_ccw_release_dev;
> vcdev->vdev.config = &virtio_ccw_config_ops;
> @@ -935,6 +1187,10 @@ module_init(virtio_ccw_init);
>
> static void __exit virtio_ccw_exit(void)
> {
> + int i;
> +
> ccw_driver_unregister(&virtio_ccw_driver);
> + for (i = 0; i < MAX_AIRQ_AREAS; i++)
> + destroy_airq_info(airq_areas[i]);
> }
> module_exit(virtio_ccw_exit);
>
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