Re: [PATCH net-next] net: mana: Add a driver for Microsoft Azure Network Adapter (MANA)

From: Leon Romanovsky <leon@kernel.org>
To: Dexuan Cui <decui@microsoft.com>
Cc: davem@davemloft.net, kuba@kernel.org, kys@microsoft.com,
	haiyangz@microsoft.com, sthemmin@microsoft.com,
	wei.liu@kernel.org, liuwe@microsoft.com, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org
Subject: Re: [PATCH net-next] net: mana: Add a driver for Microsoft Azure Network Adapter (MANA)
Date: Wed, 7 Apr 2021 11:10:08 +0300	[thread overview]
Message-ID: <YG1o4LXVllXfkUYO@unreal> (raw)
In-Reply-To: <20210406232321.12104-1-decui@microsoft.com>

On Tue, Apr 06, 2021 at 04:23:21PM -0700, Dexuan Cui wrote:
> Add a VF driver for Microsoft Azure Network Adapter (MANA) that will be
> available in the future.
> 
> Co-developed-by: Haiyang Zhang <haiyangz@microsoft.com>
> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> ---
>  MAINTAINERS                                   |    4 +-
>  drivers/net/ethernet/Kconfig                  |    1 +
>  drivers/net/ethernet/Makefile                 |    1 +
>  drivers/net/ethernet/microsoft/Kconfig        |   29 +
>  drivers/net/ethernet/microsoft/Makefile       |    5 +
>  drivers/net/ethernet/microsoft/mana/Makefile  |    6 +
>  drivers/net/ethernet/microsoft/mana/gdma.h    |  731 +++++++
>  .../net/ethernet/microsoft/mana/gdma_main.c   | 1500 +++++++++++++
>  .../net/ethernet/microsoft/mana/hw_channel.c  |  851 ++++++++
>  .../net/ethernet/microsoft/mana/hw_channel.h  |  181 ++
>  drivers/net/ethernet/microsoft/mana/mana.h    |  529 +++++
>  drivers/net/ethernet/microsoft/mana/mana_en.c | 1861 +++++++++++++++++
>  .../ethernet/microsoft/mana/mana_ethtool.c    |  276 +++
>  .../net/ethernet/microsoft/mana/shm_channel.c |  290 +++
>  .../net/ethernet/microsoft/mana/shm_channel.h |   19 +
>  15 files changed, 6283 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/net/ethernet/microsoft/Kconfig
>  create mode 100644 drivers/net/ethernet/microsoft/Makefile
>  create mode 100644 drivers/net/ethernet/microsoft/mana/Makefile
>  create mode 100644 drivers/net/ethernet/microsoft/mana/gdma.h
>  create mode 100644 drivers/net/ethernet/microsoft/mana/gdma_main.c
>  create mode 100644 drivers/net/ethernet/microsoft/mana/hw_channel.c
>  create mode 100644 drivers/net/ethernet/microsoft/mana/hw_channel.h
>  create mode 100644 drivers/net/ethernet/microsoft/mana/mana.h
>  create mode 100644 drivers/net/ethernet/microsoft/mana/mana_en.c
>  create mode 100644 drivers/net/ethernet/microsoft/mana/mana_ethtool.c
>  create mode 100644 drivers/net/ethernet/microsoft/mana/shm_channel.c
>  create mode 100644 drivers/net/ethernet/microsoft/mana/shm_channel.h

<...>

> +int gdma_verify_vf_version(struct pci_dev *pdev)
> +{
> +	struct gdma_context *gc = pci_get_drvdata(pdev);
> +	struct gdma_verify_ver_req req = { 0 };
> +	struct gdma_verify_ver_resp resp = { 0 };
> +	int err;
> +
> +	gdma_init_req_hdr(&req.hdr, GDMA_VERIFY_VF_DRIVER_VERSION,
> +			  sizeof(req), sizeof(resp));
> +
> +	req.protocol_ver_min = GDMA_PROTOCOL_FIRST;
> +	req.protocol_ver_max = GDMA_PROTOCOL_LAST;
> +
> +	err = gdma_send_request(gc, sizeof(req), &req, sizeof(resp), &resp);
> +	if (err || resp.hdr.status) {
> +		pr_err("VfVerifyVersionOutput: %d, status=0x%x\n", err,
> +		       resp.hdr.status);
> +		return -EPROTO;
> +	}
> +
> +	return 0;
> +}

<...>

> +static int gdma_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> +{
> +	struct gdma_context *gc;
> +	void __iomem *bar0_va;
> +	int bar = 0;
> +	int err;
> +
> +	err = pci_enable_device(pdev);
> +	if (err)
> +		return -ENXIO;
> +
> +	pci_set_master(pdev);
> +
> +	err = pci_request_regions(pdev, "gdma");
> +	if (err)
> +		goto disable_dev;
> +
> +	err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
> +	if (err)
> +		goto release_region;
> +
> +	err = -ENOMEM;
> +	gc = vzalloc(sizeof(*gc));
> +	if (!gc)
> +		goto release_region;
> +
> +	bar0_va = pci_iomap(pdev, bar, 0);
> +	if (!bar0_va)
> +		goto free_gc;
> +
> +	gc->bar0_va = bar0_va;
> +	gc->pci_dev = pdev;
> +
> +	pci_set_drvdata(pdev, gc);
> +
> +	gdma_init_registers(pdev);
> +
> +	shm_channel_init(&gc->shm_channel, gc->shm_base);
> +
> +	err = gdma_setup_irqs(pdev);
> +	if (err)
> +		goto unmap_bar;
> +
> +	mutex_init(&gc->eq_test_event_mutex);
> +
> +	err = hwc_create_channel(gc);
> +	if (err)
> +		goto remove_irq;
> +
> +	err = gdma_verify_vf_version(pdev);
> +	if (err)
> +		goto remove_irq;

Will this VF driver be used in the guest VM? What will prevent from users to change it? 
I think that such version negotiation scheme is not allowed.

Thanks