linux-kernel - Re: [PATCH net-next, 3/6] net/mlx5: Add wrappers for HyperV PCIe operations

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Message-ID: <f81d2a27-cedc-40ca-daf6-8f3053cc2d38@mellanox.com>
Date:   Thu, 15 Aug 2019 11:34:36 +0000
From:   Eran Ben Elisha <eranbe@...lanox.com>
To:     Mark Bloch <markb@...lanox.com>, haiyangz <haiyangz@...rosoft.com>,
        "sashal@...nel.org" <sashal@...nel.org>,
        "davem@...emloft.net" <davem@...emloft.net>,
        Saeed Mahameed <saeedm@...lanox.com>,
        "leon@...nel.org" <leon@...nel.org>,
        "lorenzo.pieralisi@....com" <lorenzo.pieralisi@....com>,
        "bhelgaas@...gle.com" <bhelgaas@...gle.com>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC:     kys <kys@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH net-next, 3/6] net/mlx5: Add wrappers for HyperV PCIe
 operations



On 8/14/2019 11:41 PM, Mark Bloch wrote:
> 
> 
> On 8/14/19 12:08 PM, Haiyang Zhang wrote:
>> From: Eran Ben Elisha <eranbe@...lanox.com>
>>
>> Add wrapper functions for HyperV PCIe read / write /
>> block_invalidate_register operations.  This will be used as an
>> infrastructure in the downstream patch for software communication.
>>
>> This will be enabled by default if CONFIG_PCI_HYPERV_MINI is set.
>>
>> Signed-off-by: Eran Ben Elisha <eranbe@...lanox.com>
>> Signed-off-by: Saeed Mahameed <saeedm@...lanox.com>
>> ---
>>   drivers/net/ethernet/mellanox/mlx5/core/Makefile |  1 +
>>   drivers/net/ethernet/mellanox/mlx5/core/lib/hv.c | 64 ++++++++++++++++++++++++
>>   drivers/net/ethernet/mellanox/mlx5/core/lib/hv.h | 22 ++++++++
>>   3 files changed, 87 insertions(+)
>>   create mode 100644 drivers/net/ethernet/mellanox/mlx5/core/lib/hv.c
>>   create mode 100644 drivers/net/ethernet/mellanox/mlx5/core/lib/hv.h
>>
>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/Makefile b/drivers/net/ethernet/mellanox/mlx5/core/Makefile
>> index 8b7edaa..a8950b1 100644
>> --- a/drivers/net/ethernet/mellanox/mlx5/core/Makefile
>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/Makefile
>> @@ -45,6 +45,7 @@ mlx5_core-$(CONFIG_MLX5_ESWITCH)   += eswitch.o eswitch_offloads.o eswitch_offlo
>>   mlx5_core-$(CONFIG_MLX5_MPFS)      += lib/mpfs.o
>>   mlx5_core-$(CONFIG_VXLAN)          += lib/vxlan.o
>>   mlx5_core-$(CONFIG_PTP_1588_CLOCK) += lib/clock.o
>> +mlx5_core-$(CONFIG_PCI_HYPERV_MINI)     += lib/hv.o
>>   
>>   #
>>   # Ipoib netdev
>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/hv.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/hv.c
>> new file mode 100644
>> index 0000000..cf08d02
>> --- /dev/null
>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/hv.c
>> @@ -0,0 +1,64 @@
>> +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
>> +// Copyright (c) 2018 Mellanox Technologies
>> +
>> +#include <linux/hyperv.h>
>> +#include "mlx5_core.h"
>> +#include "lib/hv.h"
>> +
>> +static int mlx5_hv_config_common(struct mlx5_core_dev *dev, void *buf, int len,
>> +				 int offset, bool read)
>> +{
>> +	int rc = -EOPNOTSUPP;
>> +	int bytes_returned;
>> +	int block_id;
>> +
>> +	if (offset % HV_CONFIG_BLOCK_SIZE_MAX || len % HV_CONFIG_BLOCK_SIZE_MAX)
>> +		return -EINVAL;
>> +
>> +	block_id = offset / HV_CONFIG_BLOCK_SIZE_MAX;
>> +
>> +	rc = read ?
>> +	     hyperv_read_cfg_blk(dev->pdev, buf,
>> +				 HV_CONFIG_BLOCK_SIZE_MAX, block_id,
>> +				 &bytes_returned) :
>> +	     hyperv_write_cfg_blk(dev->pdev, buf,
>> +				  HV_CONFIG_BLOCK_SIZE_MAX, block_id);
>> +
>> +	/* Make sure len bytes were read successfully  */
>> +	if (read)
>> +		rc |= !(len == bytes_returned);
>> +
>> +	if (rc) {
>> +		mlx5_core_err(dev, "Failed to %s hv config, err = %d, len = %d, offset = %d\n",
>> +			      read ? "read" : "write", rc, len,
>> +			      offset);
>> +		return rc;
>> +	}
>> +
>> +	return 0;
>> +}
> 
> This seems out of place why not expose this function as part of hyperv and mlx5
> will just pass the pdev.
> 
The HV driver works with block chunks. I found it less convenience to do 
so directly, so I add a small wrapper for mlx5 core.

Haiyangz,
Do you see a reason to export this callback style from the HYPERV level 
instead?

>> +
>> +int mlx5_hv_read_config(struct mlx5_core_dev *dev, void *buf, int len,
>> +			int offset)
>> +{
>> +	return mlx5_hv_config_common(dev, buf, len, offset, true);
>> +}
>> +
>> +int mlx5_hv_write_config(struct mlx5_core_dev *dev, void *buf, int len,
>> +			 int offset)
>> +{
>> +	return mlx5_hv_config_common(dev, buf, len, offset, false);
>> +}
>> +
>> +int mlx5_hv_register_invalidate(struct mlx5_core_dev *dev, void *context,
>> +				void (*block_invalidate)(void *context,
>> +							 u64 block_mask))
>> +{
>> +	return hyperv_reg_block_invalidate(dev->pdev, context,
>> +					   block_invalidate);
>> +}
>> +
>> +void mlx5_hv_unregister_invalidate(struct mlx5_core_dev *dev)
>> +{
>> +	hyperv_reg_block_invalidate(dev->pdev, NULL, NULL);
>> +}
>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/hv.h b/drivers/net/ethernet/mellanox/mlx5/core/lib/hv.h
>> new file mode 100644
>> index 0000000..7f69771
>> --- /dev/null
>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/hv.h
>> @@ -0,0 +1,22 @@
>> +/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
>> +/* Copyright (c) 2019 Mellanox Technologies. */
>> +
>> +#ifndef __LIB_HV_H__
>> +#define __LIB_HV_H__
>> +
>> +#if IS_ENABLED(CONFIG_PCI_HYPERV_MINI)
>> +
>> +#include <linux/hyperv.h>
>> +#include <linux/mlx5/driver.h>
>> +
>> +int mlx5_hv_read_config(struct mlx5_core_dev *dev, void *buf, int len,
>> +			int offset);
>> +int mlx5_hv_write_config(struct mlx5_core_dev *dev, void *buf, int len,
>> +			 int offset);
>> +int mlx5_hv_register_invalidate(struct mlx5_core_dev *dev, void *context,
>> +				void (*block_invalidate)(void *context,
>> +							 u64 block_mask));
>> +void mlx5_hv_unregister_invalidate(struct mlx5_core_dev *dev);
>> +#endif
>> +
>> +#endif /* __LIB_HV_H__ */
>>
> 
> Mark
>