On 22.10.20 10:23, Janosch Frank wrote:
> Diag318 fencing needs to be determined on the current VM PV state and
> not on the state that the VM has when we create the CPU model.
>
> Signed-off-by: Janosch Frank <fran...@linux.ibm.com>
> Reported-by: Marc Hartmayer <mhart...@linux.ibm.com>
> Reviewed-by: Christian Borntraeger <borntrae...@de.ibm.com>
> Fixes: fabdada935 ("s390: guest support for diagnose 0x318")
> ---
>
> If you're sure that this is what you want, then I'll send a v2 of the
> patch set.
So that's going to be the first CPU feature that gets suppressed in PC
mode - which seems to be what we want.
diag318_needed() will return false, resulting in vmstate_diag318() not
being included in the migration stream (I know, we don't support
migration yet for PV).
I don't see where diag318 would get reset during a reipl - is it
expected to be persistent when switching in/out of PV, or when reipling
etc..?
>
> ---
> target/s390x/cpu_features.c | 5 +++++
> target/s390x/cpu_features.h | 4 ++++
> target/s390x/cpu_models.c | 4 ++++
> target/s390x/kvm.c | 3 +--
> 4 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/target/s390x/cpu_features.c b/target/s390x/cpu_features.c
> index 31ea8df246..42fe0bf4ca 100644
> --- a/target/s390x/cpu_features.c
> +++ b/target/s390x/cpu_features.c
> @@ -14,6 +14,7 @@
> #include "qemu/osdep.h"
> #include "qemu/module.h"
> #include "cpu_features.h"
> +#include "hw/s390x/pv.h"
>
> #define DEF_FEAT(_FEAT, _NAME, _TYPE, _BIT, _DESC) \
> [S390_FEAT_##_FEAT] = { \
> @@ -105,6 +106,10 @@ void s390_fill_feat_block(const S390FeatBitmap features,
> S390FeatType type,
> }
> feat = find_next_bit(features, S390_FEAT_MAX, feat + 1);
> }
> +
> + if (type == S390_FEAT_TYPE_SCLP_FAC134 && s390_is_pv()) {
> + clear_be_bit(s390_feat_def(S390_FEAT_DIAG_318)->bit, data);
> + }
> }
>
> void s390_add_from_feat_block(S390FeatBitmap features, S390FeatType type,
> diff --git a/target/s390x/cpu_features.h b/target/s390x/cpu_features.h
> index ef52ffce83..87463f064d 100644
> --- a/target/s390x/cpu_features.h
> +++ b/target/s390x/cpu_features.h
> @@ -81,6 +81,10 @@ const S390FeatGroupDef *s390_feat_group_def(S390FeatGroup
> group);
>
> #define BE_BIT_NR(BIT) (BIT ^ (BITS_PER_LONG - 1))
>
> +static inline void clear_be_bit(unsigned int bit_nr, uint8_t *array)
> +{
> + array[bit_nr / 8] &= ~(0x80 >> (bit_nr % 8));
> +}
> static inline void set_be_bit(unsigned int bit_nr, uint8_t *array)
> {
> array[bit_nr / 8] |= 0x80 >> (bit_nr % 8);
> diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
> index ca484bfda7..461e0b8f4a 100644
> --- a/target/s390x/cpu_models.c
> +++ b/target/s390x/cpu_models.c
> @@ -29,6 +29,7 @@
> #include "hw/pci/pci.h"
> #endif
> #include "qapi/qapi-commands-machine-target.h"
> +#include "hw/s390x/pv.h"
>
> #define CPUDEF_INIT(_type, _gen, _ec_ga, _mha_pow, _hmfai, _name, _desc) \
> { \
> @@ -238,6 +239,9 @@ bool s390_has_feat(S390Feat feat)
> }
> return 0;
> }
> + if (feat == S390_FEAT_DIAG_318 && s390_is_pv()) {
> + return false;
> + }
> return test_bit(feat, cpu->model->features);
> }
>
> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
> index f13eff688c..baa070fdf7 100644
> --- a/target/s390x/kvm.c
> +++ b/target/s390x/kvm.c
> @@ -2498,8 +2498,7 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model,
> Error **errp)
> */
> set_bit(S390_FEAT_EXTENDED_LENGTH_SCCB, model->features);
>
> - /* DIAGNOSE 0x318 is not supported under protected virtualization */
> - if (!s390_is_pv() && kvm_check_extension(kvm_state,
> KVM_CAP_S390_DIAG318)) {
> + if (kvm_check_extension(kvm_state, KVM_CAP_S390_DIAG318)) {
> set_bit(S390_FEAT_DIAG_318, model->features);
> }
>
>
--
Thanks,
David / dhildenb
