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Re: [PATCH] s390x: pv: Fix diag318 PV fencing
From: |
Janosch Frank |
Subject: |
Re: [PATCH] s390x: pv: Fix diag318 PV fencing |
Date: |
Thu, 22 Oct 2020 10:39:47 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 |
On 10/22/20 10:32 AM, David Hildenbrand wrote:
> 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 <frankja@linux.ibm.com>
>> Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
>> Reviewed-by: Christian Borntraeger <borntraeger@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).
Well either you have it and need to migrate it or you don't.
As it doesn't persist over IPLs, that should not be a problem, no?
>
> 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..?
That's actually another bug we need to address. Diag318 will need to be
reset on a diag308 reset instead of when doing the cpu resets...
>
>>
>> ---
>> 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);
>> }
>>
>>
>
>
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- Re: [PATCH 1/2] s390x: pv: Remove sclp boundary checks, (continued)
- [PATCH 2/2] s390x: pv: Fix diag318 PV fencing, Janosch Frank, 2020/10/21
- Re: [PATCH 2/2] s390x: pv: Fix diag318 PV fencing, David Hildenbrand, 2020/10/21
- Re: [PATCH 2/2] s390x: pv: Fix diag318 PV fencing, Janosch Frank, 2020/10/21
- Re: [PATCH 2/2] s390x: pv: Fix diag318 PV fencing, David Hildenbrand, 2020/10/21
- [PATCH] s390x: pv: Fix diag318 PV fencing, Janosch Frank, 2020/10/22
- Re: [PATCH] s390x: pv: Fix diag318 PV fencing, David Hildenbrand, 2020/10/22
- Re: [PATCH] s390x: pv: Fix diag318 PV fencing,
Janosch Frank <=
- Re: [PATCH] s390x: pv: Fix diag318 PV fencing, David Hildenbrand, 2020/10/22
- Re: [PATCH] s390x: pv: Fix diag318 PV fencing, Halil Pasic, 2020/10/22
- Re: [PATCH] s390x: pv: Fix diag318 PV fencing, David Hildenbrand, 2020/10/22