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Date:   Fri, 8 Nov 2019 19:55:35 +0800
From:   Zhu Lingshan <lingshan.zhu@...ux.intel.com>
To:     "Michael S. Tsirkin" <mst@...hat.com>,
        Zhu Lingshan <lingshan.zhu@...el.com>
Cc:     jasowang@...hat.com, alex.williamson@...hat.com,
        linux-kernel@...r.kernel.org,
        virtualization@...ts.linux-foundation.org, kvm@...r.kernel.org,
        netdev@...r.kernel.org, dan.daly@...el.com,
        cunming.liang@...el.com, tiwei.bie@...el.com, jason.zeng@...el.com
Subject: Re: [PATCH 1/2] IFC hardware operation layer


On 11/5/2019 7:29 PM, Michael S. Tsirkin wrote:
> On Tue, Nov 05, 2019 at 05:37:39PM +0800, Zhu Lingshan wrote:
>> This commit introduced ifcvf_base layer, which handles hardware
>> operations and configurations.
>>
>> Signed-off-by: Zhu Lingshan <lingshan.zhu@...el.com>
>> ---
>>   drivers/vhost/ifcvf/ifcvf_base.c | 344 +++++++++++++++++++++++++++++++++++++++
>>   drivers/vhost/ifcvf/ifcvf_base.h | 132 +++++++++++++++
>>   2 files changed, 476 insertions(+)
>>   create mode 100644 drivers/vhost/ifcvf/ifcvf_base.c
>>   create mode 100644 drivers/vhost/ifcvf/ifcvf_base.h
>>
>> diff --git a/drivers/vhost/ifcvf/ifcvf_base.c b/drivers/vhost/ifcvf/ifcvf_base.c
>> new file mode 100644
>> index 0000000..0659f41
>> --- /dev/null
>> +++ b/drivers/vhost/ifcvf/ifcvf_base.c
>> @@ -0,0 +1,344 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (C) 2019 Intel Corporation.
>> + */
>> +
>> +#include "ifcvf_base.h"
>> +
>> +static void *get_cap_addr(struct ifcvf_hw *hw, struct virtio_pci_cap *cap)
>> +{
>> +	struct ifcvf_adapter *ifcvf;
>> +	u32 length, offset;
>> +	u8 bar;
>> +
>> +	length = le32_to_cpu(cap->length);
>> +	offset = le32_to_cpu(cap->offset);
>> +	bar = le32_to_cpu(cap->bar);
>> +
>> +	ifcvf = container_of(hw, struct ifcvf_adapter, vf);
>> +
>> +	if (bar >= IFCVF_PCI_MAX_RESOURCE) {
>> +		IFC_DBG(ifcvf->dev,
>> +			"Invalid bar number %u to get capabilities.\n", bar);
>> +		return NULL;
>> +	}
>> +
>> +	if (offset + length < offset) {
>> +		IFC_DBG(ifcvf->dev, "offset(%u) + length(%u) overflows\n",
>> +			offset, length);
>> +		return NULL;
>> +	}
>> +
>> +	if (offset + length > hw->mem_resource[cap->bar].len) {
>> +		IFC_DBG(ifcvf->dev,
>> +			"offset(%u) + len(%u) overflows bar%u to get capabilities.\n",
>> +			offset, length, bar);
>> +		return NULL;
>> +	}
>> +
>> +	return hw->mem_resource[bar].addr + offset;
>> +}
>> +
>> +int ifcvf_read_config_range(struct pci_dev *dev,
>> +			uint32_t *val, int size, int where)
>> +{
>> +	int ret, i;
>> +
>> +	for (i = 0; i < size; i += 4) {
>> +		ret = pci_read_config_dword(dev, where + i, val + i / 4);
>> +		if (ret < 0)
>> +			return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +int ifcvf_init_hw(struct ifcvf_hw *hw, struct pci_dev *dev)
>> +{
>> +	struct virtio_pci_cap cap;
>> +	u16 notify_off;
>> +	int ret;
>> +	u8 pos;
>> +	u32 i;
>> +
>> +	ret = pci_read_config_byte(dev, PCI_CAPABILITY_LIST, &pos);
>> +
>> +	if (ret < 0) {
>> +		IFC_ERR(&dev->dev, "Failed to read PCI capability list.\n");
>> +		return -EIO;
>> +	}
>> +
>> +	while (pos) {
>> +		ret = ifcvf_read_config_range(dev, (u32 *)&cap,
>> +					      sizeof(cap), pos);
>> +
>> +		if (ret < 0) {
>> +			IFC_ERR(&dev->dev, "Failed to get PCI capability at %x",
>> +				pos);
>> +			break;
>> +		}
>> +
>> +		if (cap.cap_vndr != PCI_CAP_ID_VNDR)
>> +			goto next;
>> +
>> +		IFC_DBG(&dev->dev, "read PCI config: config type: %u, PCI bar: %u,\
>> +			 PCI bar offset: %u, PCI config len: %u.\n",
>> +			cap.cfg_type, cap.bar, cap.offset, cap.length);
>> +
>> +		switch (cap.cfg_type) {
>> +		case VIRTIO_PCI_CAP_COMMON_CFG:
>> +			hw->common_cfg = get_cap_addr(hw, &cap);
>> +			IFC_INFO(&dev->dev, "hw->common_cfg = %p.\n",
>> +				 hw->common_cfg);
>> +			break;
>> +		case VIRTIO_PCI_CAP_NOTIFY_CFG:
>> +			pci_read_config_dword(dev, pos + sizeof(cap),
>> +					      &hw->notify_off_multiplier);
>> +			hw->notify_bar = cap.bar;
>> +			hw->notify_base = get_cap_addr(hw, &cap);
>> +			IFC_INFO(&dev->dev, "hw->notify_base = %p.\n",
>> +				 hw->notify_base);
>> +			break;
>> +		case VIRTIO_PCI_CAP_ISR_CFG:
>> +			hw->isr = get_cap_addr(hw, &cap);
>> +			IFC_INFO(&dev->dev, "hw->isr = %p.\n", hw->isr);
>> +			break;
>> +		case VIRTIO_PCI_CAP_DEVICE_CFG:
>> +			hw->net_cfg = get_cap_addr(hw, &cap);
>> +			IFC_INFO(&dev->dev, "hw->net_cfg = %p.\n", hw->net_cfg);
>> +			break;
>> +		}
>> +next:
>> +		pos = cap.cap_next;
>> +	}
>> +
>> +	if (hw->common_cfg == NULL || hw->notify_base == NULL ||
>> +	    hw->isr == NULL || hw->net_cfg == NULL) {
>> +		IFC_DBG(&dev->dev, "Incomplete PCI capabilities.\n");
>> +		return -1;
>> +	}
>> +
>> +	for (i = 0; i < IFCVF_MAX_QUEUE_PAIRS * 2; i++) {
>> +		iowrite16(i, &hw->common_cfg->queue_select);
>> +		notify_off = ioread16(&hw->common_cfg->queue_notify_off);
>> +		hw->notify_addr[i] = (void *)((u8 *)hw->notify_base +
>> +				     notify_off * hw->notify_off_multiplier);
>> +	}
>> +
>> +	hw->lm_cfg = hw->mem_resource[IFCVF_LM_BAR].addr;
>> +
>> +	IFC_DBG(&dev->dev, "PCI capability mapping: common cfg: %p,\
>> +		notify base: %p\n, isr cfg: %p, device cfg: %p,\
>> +		multiplier: %u\n",
>> +		hw->common_cfg, hw->notify_base, hw->isr,
>> +		hw->net_cfg, hw->notify_off_multiplier);
>> +
>> +	return 0;
>> +}
>> +
>> +u8 ifcvf_get_status(struct ifcvf_hw *hw)
>> +{
>> +	u8 old_gen, new_gen, status;
>> +
>> +	do {
>> +		old_gen = ioread8(&hw->common_cfg->config_generation);
>> +		status = ioread8(&hw->common_cfg->device_status);
>> +		new_gen = ioread8(&hw->common_cfg->config_generation);
>> +	} while (old_gen != new_gen);
>> +
>> +	return status;
>> +}
>> +
>> +void ifcvf_set_status(struct ifcvf_hw *hw, u8 status)
>> +{
>> +	iowrite8(status, &hw->common_cfg->device_status);
>> +}
>> +
>> +void ifcvf_reset(struct ifcvf_hw *hw)
>> +{
>> +	ifcvf_set_status(hw, 0);
>> +	ifcvf_get_status(hw);
>> +}
>> +
>> +static void ifcvf_add_status(struct ifcvf_hw *hw, u8 status)
>> +{
>> +	if (status != 0)
>> +		status |= ifcvf_get_status(hw);
>> +
>> +	ifcvf_set_status(hw, status);
>> +	ifcvf_get_status(hw);
>> +}
>> +
>> +u64 ifcvf_get_features(struct ifcvf_hw *hw)
>> +{
>> +	struct virtio_pci_common_cfg *cfg = hw->common_cfg;
>> +	u32 features_lo, features_hi;
>> +
>> +	iowrite32(0, &cfg->device_feature_select);
>> +	features_lo = ioread32(&cfg->device_feature);
>> +
>> +	iowrite32(1, &cfg->device_feature_select);
>> +	features_hi = ioread32(&cfg->device_feature);
>> +
>> +	return ((u64)features_hi << 32) | features_lo;
>> +}
>> +
>> +void ifcvf_read_net_config(struct ifcvf_hw *hw, u64 offset,
>> +		       void *dst, int length)
>> +{
>> +	u8 old_gen, new_gen, *p;
>> +	int i;
>> +
>> +	WARN_ON(offset + length > sizeof (struct ifcvf_net_config));
>> +
>> +	do {
>> +		old_gen = ioread8(&hw->common_cfg->config_generation);
>> +		p = dst;
>> +
>> +		for (i = 0; i < length; i++)
>> +			*p++ = ioread8((u8 *)hw->net_cfg + offset + i);
>> +
>> +		new_gen = ioread8(&hw->common_cfg->config_generation);
>> +	} while (old_gen != new_gen);
>> +}
>> +
>> +void ifcvf_write_net_config(struct ifcvf_hw *hw, u64 offset,
>> +			    const void *src, int length)
>> +{
>> +	const u8 *p;
>> +	int i;
>> +
>> +	p = src;
>> +	WARN_ON(offset + length > sizeof (struct ifcvf_net_config));
>> +
>> +	for (i = 0; i < length; i++)
>> +		iowrite8(*p++, (u8 *)hw->net_cfg + offset + i);
>> +}
>> +
>> +static void ifcvf_set_features(struct ifcvf_hw *hw, u64 features)
>> +{
>> +	struct virtio_pci_common_cfg *cfg = hw->common_cfg;
>> +
>> +	iowrite32(0, &cfg->guest_feature_select);
>> +	iowrite32(features & ((1ULL << 32) - 1), &cfg->guest_feature);
>> +
>> +	iowrite32(1, &cfg->guest_feature_select);
>> +	iowrite32(features >> 32, &cfg->guest_feature);
>> +}
>> +
>> +static int ifcvf_config_features(struct ifcvf_hw *hw)
>> +{
>> +	struct ifcvf_adapter *ifcvf;
>> +
>> +	ifcvf =	container_of(hw, struct ifcvf_adapter, vf);
>> +	ifcvf_set_features(hw, hw->req_features);
>> +	ifcvf_add_status(hw, VIRTIO_CONFIG_S_FEATURES_OK);
>> +
>> +	if (!(ifcvf_get_status(hw) & VIRTIO_CONFIG_S_FEATURES_OK)) {
>> +		IFC_ERR(ifcvf->dev, "Failed to set FEATURES_OK status\n");
>> +		return -EIO;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +void io_write64_twopart(u64 val, u32 *lo, u32 *hi)
>> +{
>> +	iowrite32(val & ((1ULL << 32) - 1), lo);
>> +	iowrite32(val >> 32, hi);
>> +}
>> +
>> +static int ifcvf_hw_enable(struct ifcvf_hw *hw)
>> +{
>> +	struct virtio_pci_common_cfg *cfg;
>> +	struct ifcvf_adapter *ifcvf;
>> +	u8 *lm_cfg;
>> +	u32 i;
>> +
>> +	ifcvf = container_of(hw, struct ifcvf_adapter, vf);
>> +	cfg = hw->common_cfg;
>> +	lm_cfg = hw->lm_cfg;
>> +	iowrite16(IFCVF_MSI_CONFIG_OFF, &cfg->msix_config);
>> +
>> +	if (ioread16(&cfg->msix_config) == VIRTIO_MSI_NO_VECTOR) {
>> +		IFC_ERR(ifcvf->dev, "No msix vector for device config.\n");
>> +		return -1;
>> +	}
>> +
>> +	for (i = 0; i < hw->nr_vring; i++) {
>> +		iowrite16(i, &cfg->queue_select);
>> +		io_write64_twopart(hw->vring[i].desc, &cfg->queue_desc_lo,
>> +				&cfg->queue_desc_hi);
>> +		io_write64_twopart(hw->vring[i].avail, &cfg->queue_avail_lo,
>> +				&cfg->queue_avail_hi);
>> +		io_write64_twopart(hw->vring[i].used, &cfg->queue_used_lo,
>> +				&cfg->queue_used_hi);
>> +		iowrite16(hw->vring[i].size, &cfg->queue_size);
>> +
>> +		*(u32 *)(lm_cfg + IFCVF_LM_RING_STATE_OFFSET +
>> +				(i / 2) * IFCVF_LM_CFG_SIZE + (i % 2) * 4) =
>> +			(u32)hw->vring[i].last_avail_idx |
>> +			((u32)hw->vring[i].last_used_idx << 16);
> Is this trying to store data into part of device memory BAR?
> If yes doing it like this isn't portable I think.
>
Hello Michael

Thanks for your comments, I will replace this with iowrite, I will use a 
variate representing the address to make it less-dirty.

>> +
>> +		iowrite16(i + IFCVF_MSI_QUEUE_OFF, &cfg->queue_msix_vector);
>> +		if (ioread16(&cfg->queue_msix_vector) ==
>> +		    VIRTIO_MSI_NO_VECTOR) {
>> +			IFC_ERR(ifcvf->dev,
>> +				"No msix vector for queue %u.\n", i);
>> +			return -1;
>> +		}
>> +
>> +		iowrite16(1, &cfg->queue_enable);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static void ifcvf_hw_disable(struct ifcvf_hw *hw)
>> +{
>> +	struct virtio_pci_common_cfg *cfg;
>> +	u32 i;
>> +
>> +	cfg = hw->common_cfg;
>> +	iowrite16(VIRTIO_MSI_NO_VECTOR, &cfg->msix_config);
>> +
>> +	for (i = 0; i < hw->nr_vring; i++) {
>> +		iowrite16(i, &cfg->queue_select);
>> +		iowrite16(0, &cfg->queue_enable);
>> +		iowrite16(VIRTIO_MSI_NO_VECTOR, &cfg->queue_msix_vector);
>> +	}
> Is it enough to write like this? don't you need to read
> in order to flush outstanding MSI?
I will add a read here. Thanks
>
>
>> +}
>> +
>> +int ifcvf_start_hw(struct ifcvf_hw *hw)
>> +{
>> +	ifcvf_reset(hw);
>> +	ifcvf_add_status(hw, VIRTIO_CONFIG_S_ACKNOWLEDGE);
>> +	ifcvf_add_status(hw, VIRTIO_CONFIG_S_DRIVER);
>> +
>> +	if (ifcvf_config_features(hw) < 0)
>> +		return -1;
>> +
>> +	if (ifcvf_hw_enable(hw) < 0)
>> +		return -1;
>> +
>> +	ifcvf_add_status(hw, VIRTIO_CONFIG_S_DRIVER_OK);
>> +
>> +	return 0;
>> +}
>> +
>> +void ifcvf_stop_hw(struct ifcvf_hw *hw)
>> +{
>> +	ifcvf_hw_disable(hw);
>> +	ifcvf_reset(hw);
>> +}
>> +
>> +void ifcvf_notify_queue(struct ifcvf_hw *hw, u16 qid)
>> +{
>> +	iowrite16(qid, hw->notify_addr[qid]);
> I suspect you didn't validate this driver with sparse, did you?
> Otherwise I think you would have noticed some warnings
> as e.g. iowrite16 requires a __iomem address.
>
will add __iomem in the header files and other defines.
>> +}
>> +
>> +u64 ifcvf_get_queue_notify_off(struct ifcvf_hw *hw, int qid)
>> +{
>> +	return (u8 *)hw->notify_addr[qid] -
>> +		(u8 *)hw->mem_resource[hw->notify_bar].addr;
> why is the cast of addr need?
this function can be removed.
>
>> +}
>> diff --git a/drivers/vhost/ifcvf/ifcvf_base.h b/drivers/vhost/ifcvf/ifcvf_base.h
>> new file mode 100644
>> index 0000000..c97f0eb
>> --- /dev/null
>> +++ b/drivers/vhost/ifcvf/ifcvf_base.h
>> @@ -0,0 +1,132 @@
>> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
>> +/*
>> + * Copyright (C) 2019 Intel Corporation.
>> + */
>> +
>> +#ifndef _IFCVF_H_
>> +#define _IFCVF_H_
>> +
>> +#include <linux/virtio_mdev_ops.h>
>> +#include <linux/mdev.h>
>> +#include <linux/pci.h>
>> +#include <linux/pci_regs.h>
>> +#include <uapi/linux/virtio_net.h>
>> +#include <uapi/linux/virtio_config.h>
>> +#include <uapi/linux/virtio_pci.h>
>> +
>> +#define IFCVF_VENDOR_ID         0x1AF4
>> +#define IFCVF_DEVICE_ID         0x1041
>
> I am confused by the above.
>
> They are used by the virtio layer right?
>
> So why isn't the id VIRTIO_ID_NET then?
without our driver, virtio-pci can drive this device, users can still 
use vfio passthrough on this device. We use VIRTIO_ID_NET in 
.get_device_id(), so virtio_mdev can match the device. 0x1041 only used 
in the id_table and the device reports 0x1041.
>
>> +#define IFCVF_SUBSYS_VENDOR_ID  0x8086
>> +#define IFCVF_SUBSYS_DEVICE_ID  0x001A
>> +
>> +#define IFCVF_MDEV_LIMIT	1
>> +
>> +/*
>> + * Some ifcvf feature bits (currently bits 28 through 31) are
>> + * reserved for the transport being used (eg. ifcvf_ring), the
>> + * rest are per-device feature bits.
>> + */
>> +#define IFCVF_TRANSPORT_F_START 28
>> +#define IFCVF_TRANSPORT_F_END   34
>> +
>> +#define IFC_SUPPORTED_FEATURES \
>> +		((1ULL << VIRTIO_NET_F_MAC)			| \
>> +		 (1ULL << VIRTIO_F_ANY_LAYOUT)			| \
>> +		 (1ULL << VIRTIO_F_VERSION_1)			| \
>> +		 (1ULL << VIRTIO_F_ORDER_PLATFORM)			| \
>> +		 (1ULL << VIRTIO_NET_F_GUEST_ANNOUNCE)		| \
>> +		 (1ULL << VIRTIO_NET_F_CTRL_VQ)			| \
>> +		 (1ULL << VIRTIO_NET_F_STATUS)			| \
>> +		 (1ULL << VIRTIO_NET_F_MRG_RXBUF)) /* not fully supported */
> what does this last one mean?
> shouldn't we clear the bit if it's incomplete?
it is supported now:)
>
>> +
>> +//Not support MQ, only one queue pair for now.
> /* comments like this pls */
sure
>
>> +#define IFCVF_MAX_QUEUE_PAIRS		1
>> +#define IFCVF_MAX_QUEUES		2
>> +
>> +#define IFCVF_QUEUE_ALIGNMENT		PAGE_SIZE
>> +
>> +#define IFCVF_MSI_CONFIG_OFF	0
>> +#define IFCVF_MSI_QUEUE_OFF	1
>> +#define IFCVF_PCI_MAX_RESOURCE	6
>> +
>> +#define IFCVF_LM_CFG_SIZE		0x40
>> +#define IFCVF_LM_RING_STATE_OFFSET	0x20
>> +#define IFCVF_LM_BAR	4
>> +
>> +#define IFCVF_32_BIT_MASK		0xffffffff
>> +
>> +#define IFC_ERR(dev, fmt, ...)	dev_err(dev, fmt, ##__VA_ARGS__)
>> +#define IFC_DBG(dev, fmt, ...)	dev_dbg(dev, fmt, ##__VA_ARGS__)
>> +#define IFC_INFO(dev, fmt, ...)	dev_info(dev, fmt, ##__VA_ARGS__)
>> +
>> +#define IFC_PRIVATE_TO_VF(adapter) \
>> +	(&((struct ifcvf_adapter *)adapter)->vf)
>> +
>> +#define IFCVF_MAX_INTR (IFCVF_MAX_QUEUE_PAIRS * 2 + 1)
>> +
>> +struct ifcvf_net_config {
>> +	u8    mac[6];
>> +	u16   status;
>> +	u16   max_virtqueue_pairs;
>> +} __packed;
> Looks like a partial copy of virtio_net_config - reuse that one instead?
sure
>
>
>> +
>> +struct ifcvf_pci_mem_resource {
>> +	/* Physical address, 0 if not resource. */
>> +	u64      phys_addr;
>> +	/* Length of the resource. */
>> +	u64      len;
>> +	/* Virtual address, NULL when not mapped. */
>> +	u8       *addr;
>> +};
>> +
>> +struct vring_info {
>> +	u64 desc;
>> +	u64 avail;
>> +	u64 used;
>> +	u16 size;
>> +	u16 last_avail_idx;
>> +	u16 last_used_idx;
>> +	bool ready;
>> +	char msix_name[256];
>> +	struct virtio_mdev_callback cb;
>> +};
>> +
>> +struct ifcvf_hw {
>> +	u8	*isr;
>> +	u8	notify_bar;
>> +	u8	*lm_cfg;
>> +	u8	nr_vring;
>> +	u16	*notify_base;
>> +	u16	*notify_addr[IFCVF_MAX_QUEUE_PAIRS * 2];
>> +	u32	notify_off_multiplier;
>> +	u64	req_features;
>> +	struct	virtio_pci_common_cfg *common_cfg;
>> +	struct	ifcvf_net_config *net_cfg;
>> +	struct	vring_info vring[IFCVF_MAX_QUEUE_PAIRS * 2];
>> +	struct	ifcvf_pci_mem_resource mem_resource[IFCVF_PCI_MAX_RESOURCE];
>> +};
>> +
>> +struct ifcvf_adapter {
>> +	struct	device *dev;
>> +	struct	mutex mdev_lock;
>> +	int	mdev_count;
>> +	int	vectors;
>> +	struct	ifcvf_hw vf;
>> +};
>> +
>> +int ifcvf_init_hw(struct ifcvf_hw *hw, struct pci_dev *dev);
>> +int ifcvf_start_hw(struct ifcvf_hw *hw);
>> +void ifcvf_stop_hw(struct ifcvf_hw *hw);
>> +void ifcvf_notify_queue(struct ifcvf_hw *hw, u16 qid);
>> +u8 ifcvf_get_linkstatus(struct ifcvf_hw *hw);
>> +void ifcvf_read_net_config(struct ifcvf_hw *hw, u64 offset,
>> +			   void *dst, int length);
>> +void ifcvf_write_net_config(struct ifcvf_hw *hw, u64 offset,
>> +			    const void *src, int length);
>> +u8 ifcvf_get_status(struct ifcvf_hw *hw);
>> +void ifcvf_set_status(struct ifcvf_hw *hw, u8 status);
>> +void io_write64_twopart(u64 val, u32 *lo, u32 *hi);
>> +void ifcvf_reset(struct ifcvf_hw *hw);
>> +u64 ifcvf_get_features(struct ifcvf_hw *hw);
>> +
>> +#endif /* _IFCVF_H_ */
>> -- 
>> 1.8.3.1

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