Re: [PATCH linux-4.19.y] PCI/MSI: Prevent MSI hardware interrupt number truncation

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Feb 26, 2024 at 04:03:46PM +0100, Thomas Gleixner wrote:
> 
> From: Vidya Sagar <vidyas@nvidia.com>
> 
> Commit db744ddd59be798c2627efbfc71f707f5a935a40 upstream.
> 
> While calculating the hardware interrupt number for a MSI interrupt, the
> higher bits (i.e. from bit-5 onwards a.k.a domain_nr >= 32) of the PCI
> domain number gets truncated because of the shifted value casting to return
> type of pci_domain_nr() which is 'int'. This for example is resulting in
> same hardware interrupt number for devices 0019:00:00.0 and 0039:00:00.0.
> 
> To address this cast the PCI domain number to 'irq_hw_number_t' before left
> shifting it to calculate the hardware interrupt number.
> 
> Please note that this fixes the issue only on 64-bit systems and doesn't
> change the behavior for 32-bit systems i.e. the 32-bit systems continue to
> have the issue. Since the issue surfaces only if there are too many PCIe
> controllers in the system which usually is the case in modern server
> systems and they don't tend to run 32-bit kernels.
> 
> Fixes: 3878eaefb89a ("PCI/MSI: Enhance core to support hierarchy irqdomain")
> Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> [ tglx: Backport to linux-4.19.y ]

Didn't apply there, are you sure this was correct?

Anyway, I fixed it up by hand...

thanks,

greg k-h