Re: [RFC PATCH v4 5/5] s390: implementing CHSC SEI for AP config change

[Thomas Huth <thuth@redhat.com>]

On 11/03/2025 16.16, Rorie Reyes wrote:
> Handle interception of the CHSC SEI instruction for requests
> indicating the guest's AP configuration has changed.
> 
> Signed-off-by: Rorie Reyes <rreyes@linux.ibm.com>
> Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com>
> Tested-by: Anthony Krowiak <akrowiak@linux.ibm.com>
> ---
>   target/s390x/ioinst.c | 11 +++++++++--
>   1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/target/s390x/ioinst.c b/target/s390x/ioinst.c
> index a944f16c25..f061c6db14 100644
> --- a/target/s390x/ioinst.c
> +++ b/target/s390x/ioinst.c
> @@ -17,6 +17,7 @@
>   #include "trace.h"
>   #include "hw/s390x/s390-pci-bus.h"
>   #include "target/s390x/kvm/pv.h"
> +#include "hw/s390x/ap-bridge.h"
>   
>   /* All I/O instructions but chsc use the s format */
>   static uint64_t get_address_from_regs(CPUS390XState *env, uint32_t ipb,
> @@ -573,13 +574,19 @@ out:
>   
>   static int chsc_sei_nt0_get_event(void *res)
>   {
> -    /* no events yet */
> +    if (s390_has_feat(S390_FEAT_AP)) {
> +        return ap_chsc_sei_nt0_get_event(res);
> +    }
> +
>       return 1;
>   }
>   
>   static int chsc_sei_nt0_have_event(void)
>   {
> -    /* no events yet */
> +    if (s390_has_feat(S390_FEAT_AP)) {
> +        return ap_chsc_sei_nt0_have_event();
> +    }
> +
>       return 0;
>   }

  Hi!

This unfortunately fails to link when configuring QEMU with the 
"--without-default-devices" configure switch:

/usr/bin/ld: libqemu-s390x-softmmu.a.p/target_s390x_ioinst.c.o: in function 
`ioinst_handle_chsc':
/tmp/qemu-mini/target/s390x/ioinst.c:587:(.text+0x1ce1): undefined reference 
to `ap_chsc_sei_nt0_have_event'
/usr/bin/ld: /tmp/qemu-mini/target/s390x/ioinst.c:578:(.text+0x1d1c): 
undefined reference to `ap_chsc_sei_nt0_get_event'
collect2: error: ld returned 1 exit status

I guess you have to rather use some callback mechanism, stubs or #ifdefs 
here instead.

  Thomas