Re: [RFC XEN PATCH v14 4/5] tools: Add new function to get gsi from dev

[Anthony PERARD <anthony.perard@vates.tech>]

On Tue, Sep 03, 2024 at 03:04:23PM +0800, Jiqian Chen wrote:
> When passthrough a device to domU, QEMU and xl tools use its gsi
> number to do pirq mapping, see QEMU code
> xen_pt_realize->xc_physdev_map_pirq, and xl code
> pci_add_dm_done->xc_physdev_map_pirq, but the gsi number is got
> from file /sys/bus/pci/devices/<sbdf>/irq, that is wrong, because
> irq is not equal with gsi, they are in different spaces, so pirq
> mapping fails.
> 
> And in current codes, there is no method to get gsi for userspace.
> For above purpose, add new function to get gsi, and the
> corresponding ioctl is implemented on linux kernel side.
> 
> Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
> Signed-off-by: Huang Rui <ray.huang@amd.com>
> Signed-off-by: Chen Jiqian <Jiqian.Chen@amd.com>
> ---
> RFC: it needs to wait for the corresponding third patch on linux kernel side to be merged.
> https://lore.kernel.org/xen-devel/20240607075109.126277-4-Jiqian.Chen@amd.com/
> ---
> v13->v14 changes:
> No.
> 
> v12->v13 changes:
> Rename the function xc_physdev_gsi_from_pcidev to xc_pcidev_get_gsi to avoid confusion with physdev namesapce.
> Move the implementation of xc_pcidev_get_gsi into xc_linux.c.
> Directly use xencall_fd(xch->xcall) in the function xc_pcidev_get_gsi instead of opening "privcmd".

Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>

Thanks,

-- 

Anthony Perard | Vates XCP-ng Developer

XCP-ng & Xen Orchestra - Vates solutions

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