Re: [PATCH 1/6] vDPA/ifcvf: get_config_size should return a value no greater than dev implementation
From: Jason Wang <jasowang@redhat.com>
Date: 2022-06-02 07:11:30
Also in:
virtualization
On Thu, Jun 2, 2022 at 10:48 AM Zhu Lingshan [off-list ref] wrote:
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ifcvf_get_config_size() should return a virtio device type specific value, however the ret_value should not be greater than the onboard size of the device implementation. E.g., for virtio_net, config_size should be the minimum value of sizeof(struct virtio_net_config) and the onboard cap size. Signed-off-by: Zhu Lingshan <redacted> --- drivers/vdpa/ifcvf/ifcvf_base.c | 8 ++++++-- drivers/vdpa/ifcvf/ifcvf_base.h | 2 ++ 2 files changed, 8 insertions(+), 2 deletions(-)diff --git a/drivers/vdpa/ifcvf/ifcvf_base.c b/drivers/vdpa/ifcvf/ifcvf_base.c index 48c4dadb0c7c..6bccc8291c26 100644 --- a/drivers/vdpa/ifcvf/ifcvf_base.c +++ b/drivers/vdpa/ifcvf/ifcvf_base.c@@ -128,6 +128,7 @@ int ifcvf_init_hw(struct ifcvf_hw *hw, struct pci_dev *pdev) break; case VIRTIO_PCI_CAP_DEVICE_CFG: hw->dev_cfg = get_cap_addr(hw, &cap); + hw->cap_dev_config_size = le32_to_cpu(cap.length);
One possible issue here is that, if the hardware have more size than spec, we may end up with a migration compatibility issue. It looks to me we'd better build the config size based on the features, e.g it looks to me for net, we should probably use offset_of(struct virtio_net_config, mtu)?
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IFCVF_DBG(pdev, "hw->dev_cfg = %p\n", hw->dev_cfg); break; }@@ -233,15 +234,18 @@ int ifcvf_verify_min_features(struct ifcvf_hw *hw, u64 features) u32 ifcvf_get_config_size(struct ifcvf_hw *hw) { struct ifcvf_adapter *adapter; + u32 net_config_size = sizeof(struct virtio_net_config); + u32 blk_config_size = sizeof(struct virtio_blk_config); + u32 cap_size = hw->cap_dev_config_size; u32 config_size; adapter = vf_to_adapter(hw); switch (hw->dev_type) { case VIRTIO_ID_NET: - config_size = sizeof(struct virtio_net_config); + config_size = cap_size >= net_config_size ? net_config_size : cap_size;
I don't get the code here, any chance that net_config_size could be zero? Thanks
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break; case VIRTIO_ID_BLOCK: - config_size = sizeof(struct virtio_blk_config); + config_size = cap_size >= blk_config_size ? blk_config_size : cap_size; break; default: config_size = 0;diff --git a/drivers/vdpa/ifcvf/ifcvf_base.h b/drivers/vdpa/ifcvf/ifcvf_base.h index 115b61f4924b..f5563f665cc6 100644 --- a/drivers/vdpa/ifcvf/ifcvf_base.h +++ b/drivers/vdpa/ifcvf/ifcvf_base.h@@ -87,6 +87,8 @@ struct ifcvf_hw { int config_irq; int vqs_reused_irq; u16 nr_vring; + /* VIRTIO_PCI_CAP_DEVICE_CFG size */ + u32 cap_dev_config_size; }; struct ifcvf_adapter { --2.31.1