On Fri, 2022-09-02 at 09:55 +0200, Pierre Morel wrote:
> When the host supports the CPU topology facility, the PTF
> instruction with function code 2 is interpreted by the SIE,
> provided that the userland hypervizor activates the interpretation
> by using the KVM_CAP_S390_CPU_TOPOLOGY KVM extension.
>
> The PTF instructions with function code 0 and 1 are intercepted
> and must be emulated by the userland hypervizor.
>
> Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
Reviewed-by: Janis Schoetterl-Glausch <scgl@xxxxxxxxxxxxx>
See note below.
> ---
> hw/s390x/cpu-topology.c | 52 ++++++++++++++++++++++++++++++
> include/hw/s390x/s390-virtio-ccw.h | 6 ++++
> target/s390x/kvm/kvm.c | 13 ++++++++
> 3 files changed, 71 insertions(+)
>
> diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
> index b6bf839e40..7dcaa28ca3 100644
> --- a/hw/s390x/cpu-topology.c
> +++ b/hw/s390x/cpu-topology.c
> @@ -20,6 +20,58 @@
> #include "hw/s390x/s390-virtio-ccw.h"
> #include "hw/s390x/cpu-topology.h"
> #include "migration/vmstate.h"
> +#include "target/s390x/cpu.h"
> +#include "hw/s390x/s390-virtio-ccw.h"
> +
> +/*
> + * s390_handle_ptf:
> + *
> + * @register 1: contains the function code
> + *
> + * Function codes 0 and 1 handle the CPU polarization.
> + * We assume an horizontal topology, the only one supported currently
> + * by Linux, consequently we answer to function code 0, requesting
> + * horizontal polarization that it is already the current polarization
> + * and reject vertical polarization request without further explanation.
> + *
> + * Function code 2 is handling topology changes and is interpreted
> + * by the SIE.
> + */
> +void s390_handle_ptf(S390CPU *cpu, uint8_t r1, uintptr_t ra)
> +{
> + CPUS390XState *env = &cpu->env;
> + uint64_t reg = env->regs[r1];
> + uint8_t fc = reg & S390_TOPO_FC_MASK;
> +
> + if (!s390_has_feat(S390_FEAT_CONFIGURATION_TOPOLOGY)) {
> + s390_program_interrupt(env, PGM_OPERATION, ra);
> + return;
I'm either expecting this function to return -1 here...
> + }
> +
> + if (env->psw.mask & PSW_MASK_PSTATE) {
> + s390_program_interrupt(env, PGM_PRIVILEGED, ra);
> + return;
> + }
> +
> + if (reg & ~S390_TOPO_FC_MASK) {
> + s390_program_interrupt(env, PGM_SPECIFICATION, ra);
> + return;
> + }
> +
> + switch (fc) {
> + case 0: /* Horizontal polarization is already set */
> + env->regs[r1] |= S390_PTF_REASON_DONE;
> + setcc(cpu, 2);
> + break;
> + case 1: /* Vertical polarization is not supported */
> + env->regs[r1] |= S390_PTF_REASON_NONE;
> + setcc(cpu, 2);
> + break;
> + default:
> + /* Note that fc == 2 is interpreted by the SIE */
> + s390_program_interrupt(env, PGM_SPECIFICATION, ra);
> + }
> +}
[...]
>
> +static int kvm_handle_ptf(S390CPU *cpu, struct kvm_run *run)
> +{
> + uint8_t r1 = (run->s390_sieic.ipb >> 20) & 0x0f;
> +
> + s390_handle_ptf(cpu, r1, RA_IGNORED);
... and this being returned here...
> +
> + return 0;
... or this function being void.
> +}
> +
> static int handle_b9(S390CPU *cpu, struct kvm_run *run, uint8_t ipa1)
> {
> int r = 0;
> @@ -1480,6 +1490,9 @@ static int handle_b9(S390CPU *cpu, struct kvm_run *run, uint8_t ipa1)
> case PRIV_B9_RPCIT:
> r = kvm_rpcit_service_call(cpu, run);
> break;
> + case PRIV_B9_PTF:
> + r = kvm_handle_ptf(cpu, run);
> + break;
> case PRIV_B9_EQBS:
> /* just inject exception */
> r = -1;
