[SPDK] Re: Can I use spdk_pci_hook_device to implement a virtual NVMe device?

[SPDK] Re: Can I use spdk_pci_hook_device to implement a virtual NVMe device?

[oscar.huang]

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Hi, Jim,

I haven't. I have no experience on creating code to trap memory access. I googled a little bit. It looks like I can use mprotect to set memory access properties so that certain signal can be triggered when the memory area is read or written. Will give it a try.

Thanks for your suggestion, Jim.

-Oscar

[SPDK] Re: Can I use spdk_pci_hook_device to implement a virtual NVMe device?

[Harris, James R]

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Hi Oscar,

Have you tried a signal handler to trap writes to the virtual BAR?  Then your handler can get the fault address and do whatever actions it needs.

-Jim


On 4/23/20, 6:30 PM, "oscar.huang(a)microchip.com" <oscar.huang(a)microchip.com> wrote:

    I'd like to create a virtual NVMe device and use SPDK NVMe APIs to operate it. It looks like spdk_pci_hook_device() can add a virtual PCI device to SPDK PCI system:

    void spdk_pci_hook_device(struct spdk_pci_driver *drv, struct spdk_pci_device *dev);

    But the struct spdk_pci_device only contains the following callbacks:
        int (*map_bar)(struct spdk_pci_device *dev, uint32_t bar, 
                   void **mapped_addr, uint64_t *phys_addr, uint64_t *size);
        int (*unmap_bar)(struct spdk_pci_device *dev, uint32_t bar, 
                 void *addr);
        int (*cfg_read)(struct spdk_pci_device *dev, void *value,
                uint32_t len, uint32_t offset);
        int (*cfg_write)(struct spdk_pci_device *dev, void *value,
                 uint32_t len, uint32_t offset);
        void (*detach)(struct spdk_pci_device *dev);

    It does not have mmio callbacks. When applications write a device memory, sometimes it needs to trigger some actions on the device. Without mmio callbacks, how to make a useful virtual device with spdk_pci_hook_device? Pls suggest. Much appreciated!
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