[PATCH v2 0/2] s390x: pv: Diag318 fixes

[PATCH v2 0/2] s390x: pv: Diag318 fixes

[Janosch Frank]

Here are two fixes for the diag318 support that fix crashes when
booting PV guests.

We're working on extending our testing to catch problems like these
earlier.


Branch:
https://gitlab.com/frankja/qemu/-/commits/bb/frankja/diag318_fixes

CI:
https://gitlab.com/frankja/qemu/-/pipelines/206174979


V2:
	* Moved fencing nto cpu model functions
	* Added rev-by and acks


Janosch Frank (2):
  s390x: pv: Remove sclp boundary checks
  s390x: pv: Fix diag318 PV fencing

 hw/s390x/sclp.c             | 5 -----
 target/s390x/cpu_features.c | 5 +++++
 target/s390x/cpu_features.h | 4 ++++
 target/s390x/cpu_models.c   | 4 ++++
 target/s390x/kvm.c          | 3 +--
 5 files changed, 14 insertions(+), 7 deletions(-)

-- 
2.25.1

[PATCH v2 1/2] s390x: pv: Remove sclp boundary checks

[Janosch Frank]

The SCLP boundary cross check is done by the Ultravisor for a
protected guest, hence we don't need to do it. As QEMU doesn't get a
valid SCCB address in protected mode this is even problematic and can
lead to QEMU reporting a false boundary cross error.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Fixes: db13387ca0 ("s390/sclp: rework sclp boundary checks")
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Marc Hartmayer <mhartmay@linux.ibm.com>
---
 hw/s390x/sclp.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
index 00f1e4648d..0cf2290826 100644
--- a/hw/s390x/sclp.c
+++ b/hw/s390x/sclp.c
@@ -285,11 +285,6 @@ int sclp_service_call_protected(CPUS390XState *env, uint64_t sccb,
         goto out_write;
     }
 
-    if (!sccb_verify_boundary(sccb, be16_to_cpu(work_sccb->h.length), code)) {
-        work_sccb->h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION);
-        goto out_write;
-    }
-
     sclp_c->execute(sclp, work_sccb, code);
 out_write:
     s390_cpu_pv_mem_write(env_archcpu(env), 0, work_sccb,
-- 
2.25.1

[PATCH v2 2/2] s390x: pv: Fix diag318 PV fencing

[Janosch Frank]

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>
Fixes: fabdada935 ("s390: guest support for diagnose 0x318")
---
 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);
     }
 
-- 
2.25.1

Re: [PATCH v2 2/2] s390x: pv: Fix diag318 PV fencing

[David Hildenbrand]

On 22.10.20 12:31, 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>
> Fixes: fabdada935 ("s390: guest support for diagnose 0x318")
> ---
>  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);
>      }
>  
> 

Acked-by: David Hildenbrand <david@redhat.com>

-- 
Thanks,

David / dhildenb

Re: [PATCH v2 2/2] s390x: pv: Fix diag318 PV fencing

[Christian Borntraeger]

On 22.10.20 12:31, 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>
> Fixes: fabdada935 ("s390: guest support for diagnose 0x318")

I prefer v1 as it is more obvious what happens, but this looks fine as well
and as David prefers this let us go with this one.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>

> ---
>  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);
>      }
>  
> 

Re: [PATCH v2 2/2] s390x: pv: Fix diag318 PV fencing

[Marc Hartmayer]

On Thu, Oct 22, 2020 at 06:31 AM -0400, Janosch Frank <frankja@linux.ibm.com> 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>
> Fixes: fabdada935 ("s390: guest support for diagnose 0x318")
> ---
>  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);
>      }
>  
> -- 
> 2.25.1

Tested-by: Marc Hartmayer <mhartmay@linux.ibm.com>

Re: [PATCH v2 0/2] s390x: pv: Diag318 fixes

[Collin Walling]

On 10/22/20 6:31 AM, Janosch Frank wrote:
> Here are two fixes for the diag318 support that fix crashes when
> booting PV guests.
> 
> We're working on extending our testing to catch problems like these
> earlier.
> 
> 
> Branch:
> https://gitlab.com/frankja/qemu/-/commits/bb/frankja/diag318_fixes
> 
> CI:
> https://gitlab.com/frankja/qemu/-/pipelines/206174979
> 
> 
> V2:
> 	* Moved fencing nto cpu model functions
> 	* Added rev-by and acks
> 
> 
> Janosch Frank (2):
>   s390x: pv: Remove sclp boundary checks
>   s390x: pv: Fix diag318 PV fencing
> 
>  hw/s390x/sclp.c             | 5 -----
>  target/s390x/cpu_features.c | 5 +++++
>  target/s390x/cpu_features.h | 4 ++++
>  target/s390x/cpu_models.c   | 4 ++++
>  target/s390x/kvm.c          | 3 +--
>  5 files changed, 14 insertions(+), 7 deletions(-)
> 

Thanks for correcting this. You've certainly received plenty of reviews
and ack's, but since this touches code I worked on:

Reviewed-by: Collin Walling <walling@linux.ibm.com>

-- 
Regards,
Collin

Stay safe and stay healthy

Re: [PATCH v2 0/2] s390x: pv: Diag318 fixes

[Cornelia Huck]

On Thu, 22 Oct 2020 06:31:33 -0400
Janosch Frank <frankja@linux.ibm.com> wrote:

> Here are two fixes for the diag318 support that fix crashes when
> booting PV guests.
> 
> We're working on extending our testing to catch problems like these
> earlier.
> 
> 
> Branch:
> https://gitlab.com/frankja/qemu/-/commits/bb/frankja/diag318_fixes
> 
> CI:
> https://gitlab.com/frankja/qemu/-/pipelines/206174979
> 
> 
> V2:
> 	* Moved fencing nto cpu model functions
> 	* Added rev-by and acks
> 
> 
> Janosch Frank (2):
>   s390x: pv: Remove sclp boundary checks
>   s390x: pv: Fix diag318 PV fencing
> 
>  hw/s390x/sclp.c             | 5 -----
>  target/s390x/cpu_features.c | 5 +++++
>  target/s390x/cpu_features.h | 4 ++++
>  target/s390x/cpu_models.c   | 4 ++++
>  target/s390x/kvm.c          | 3 +--
>  5 files changed, 14 insertions(+), 7 deletions(-)
> 

Thanks, applied.