[GIT PULL 0/1] s390 fixes for 6.1-rc7/8

[GIT PULL 0/1] s390 fixes for 6.1-rc7/8

[Janosch Frank]

Dear Paolo,

please pull Thomas' fix for VSIE.
We deem it to be low risk and it survived a day in our CI without any errors.
It's a bit late so let's see if it makes 6.1 or 6.2.


The following changes since commit eb7081409f94a9a8608593d0fb63a1aa3d6f95d8:

  Linux 6.1-rc6 (2022-11-20 16:02:16 -0800)

are available in the Git repository at:

  https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux.git tags/kvm-s390-master-6.1-2

for you to fetch changes up to 0dd4cdccdab3d74bd86b868768a7dca216bcce7e:

  KVM: s390: vsie: Fix the initialization of the epoch extension (epdx) field (2022-11-24 14:43:17 +0100)

----------------------------------------------------------------
VSIE epdx shadowing fix

----------------------------------------------------------------
Thomas Huth (1):
      KVM: s390: vsie: Fix the initialization of the epoch extension (epdx) field

 arch/s390/kvm/vsie.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Thomas Huth (1):
  KVM: s390: vsie: Fix the initialization of the epoch extension (epdx)
    field

 arch/s390/kvm/vsie.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

-- 
2.38.1

[GIT PULL 1/1] KVM: s390: vsie: Fix the initialization of the epoch extension (epdx) field

[Janosch Frank]

From: Thomas Huth <thuth@redhat.com>

We recently experienced some weird huge time jumps in nested guests when
rebooting them in certain cases. After adding some debug code to the epoch
handling in vsie.c (thanks to David Hildenbrand for the idea!), it was
obvious that the "epdx" field (the multi-epoch extension) did not get set
to 0xff in case the "epoch" field was negative.
Seems like the code misses to copy the value from the epdx field from
the guest to the shadow control block. By doing so, the weird time
jumps are gone in our scenarios.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=2140899
Fixes: 8fa1696ea781 ("KVM: s390: Multiple Epoch Facility support")
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Cc: stable@vger.kernel.org # 4.19+
Link: https://lore.kernel.org/r/20221123090833.292938-1-thuth@redhat.com
Message-Id: <20221123090833.292938-1-thuth@redhat.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
---
 arch/s390/kvm/vsie.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index 94138f8f0c1c..ace2541ababd 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -546,8 +546,10 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_CEI))
 		scb_s->eca |= scb_o->eca & ECA_CEI;
 	/* Epoch Extension */
-	if (test_kvm_facility(vcpu->kvm, 139))
+	if (test_kvm_facility(vcpu->kvm, 139)) {
 		scb_s->ecd |= scb_o->ecd & ECD_MEF;
+		scb_s->epdx = scb_o->epdx;
+	}
 
 	/* etoken */
 	if (test_kvm_facility(vcpu->kvm, 156))
-- 
2.38.1

Re: [GIT PULL 0/1] s390 fixes for 6.1-rc7/8

[Paolo Bonzini]

On Fri, Nov 25, 2022 at 9:55 AM Janosch Frank <frankja@linux.ibm.com> wrote:
>
> Dear Paolo,
>
> please pull Thomas' fix for VSIE.
> We deem it to be low risk and it survived a day in our CI without any errors.
> It's a bit late so let's see if it makes 6.1 or 6.2.
>
>
> The following changes since commit eb7081409f94a9a8608593d0fb63a1aa3d6f95d8:
>
>   Linux 6.1-rc6 (2022-11-20 16:02:16 -0800)
>
> are available in the Git repository at:
>
>   https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux.git tags/kvm-s390-master-6.1-2
>
> for you to fetch changes up to 0dd4cdccdab3d74bd86b868768a7dca216bcce7e:
>
>   KVM: s390: vsie: Fix the initialization of the epoch extension (epdx) field (2022-11-24 14:43:17 +0100)

Pulled, thanks.

Paolo

>
> ----------------------------------------------------------------
> VSIE epdx shadowing fix
>
> ----------------------------------------------------------------
> Thomas Huth (1):
>       KVM: s390: vsie: Fix the initialization of the epoch extension (epdx) field
>
>  arch/s390/kvm/vsie.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> Thomas Huth (1):
>   KVM: s390: vsie: Fix the initialization of the epoch extension (epdx)
>     field
>
>  arch/s390/kvm/vsie.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> --
> 2.38.1
>