On Thu, Jun 05, 2025 at 12:41:06PM +0200, Jan Beulich wrote: > On 31.05.2025 14:54, Stewart Hildebrand wrote: > > Currently, Xen vPCI refuses BAR writes if the BAR is mapped in p2m. If > > firmware initializes a 32-bit BAR to a bad address, Linux may try to > > write a new address to the BAR without disabling memory decoding. Since > > Xen refuses such writes, the BAR (and thus PCI device) will be > > non-functional. > > Doing this for 32-bit BARs only, with not even an outline what to do about > the same issue with 64-bit ones, seems like it won't buy us very much.
IIRC Linux will disable decoding in the common case when updating the position of a 64bit BAR. However it won't disable decoding for 32bit BARs. I think that's why Stewart cares more about the 32bit case than the 64bit one. Regards, Roger.
