Re: [PATCH v1] s390x/pci: fix interrupt blocking by returning only the device's summary bit

[Eric Farman <farman@linux.ibm.com>]

On Wed, 2025-10-01 at 10:39 -0500, Jaehoon Kim wrote:
> Previously, set_ind_atomic() returned the entire byte containing
> multiple summary bits. This meant that if any other summary bit in the
> byte was set, interrupt injection could be incorrectly blocked, even
> when the current device's summary bit was not set. As a result, the
> guest could remain blocked after I/O completion during FIO tests.
> 
> This patch replaces set_ind_atomic() with set_ind_bit_atomic(), which
> returns true if the bit was set by this function, and false if it was
> already set or mapping failed. Interrupts are now blocked only when
> the device's own summary bit was not previously set, avoiding
> unintended blocking when multiple PCI summary bits exist within the
> same byte.
> 
> Signed-off-by: Jaehoon Kim <jhkim@linux.ibm.com>
> ---
>  hw/s390x/s390-pci-bus.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)

Reviewed-by: Eric Farman <farman@linux.ibm.com>