On 28/10/2021, Amol <suratiamol@xxxxxxxxx> wrote: > On 28/10/2021, Amol <suratiamol@xxxxxxxxx> wrote: >> Hello, >> >> If pci_check_and_set_intx_mask is called with the intention of masking, >> and if there indeed is an IRQ pending, then the comparison >> "mask != irq_pending" evaluates to false: the 'mask' variable is 1, and > > Correction: Evaluates to true. Causes the function to return without > masking. > >> 'irq_pending' is 0x80, in that case. >> >> This state causes the function to return without masking, contrary to the >> behaviour expected of it as given by a comment: >> >> "Check if the device dev has its INTx line asserted, mask it and return >> true >> in that case. False is returned if no interrupt was pending." >> >> My vfio/pcipassthrough setup sees INTx line asserted as the VM is being >> shutdown, but the line is not masked; the host kernel panics saying >> "nobody cared" - there's no handler. >> >> Is the inconsistency with the pci intx masking really a problem, or just >> a >> misunderstanding on my part? It is indeed a misunderstanding on my part. I missed the fact that the datatype involved here is _Bool; the compiler must be emitting extra instructions to convert non-zero values to 1. Apologies for the spam. >> >> Thanks, >> Amol >> >
