[PATCH 1/2] KVM: s390: Fix lpsw/e breaking event handling

Janosch Frank
2026-03-23T15:36:53Z

LPSW and LPSWE need to set the gbea on completion but currently don't.
Time to fix this up.

LPSWEY was designed to not set the bear.

Fixes: 48a3e950f4cee ("KVM: s390: Add support for machine checks.")
Reported-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
---
arch/s390/kvm/priv.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index a3250ad83a8e..cc0553da14cb 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -714,12 +714,13 @@ int kvm_s390_handle_lpsw(struct kvm_vcpu *vcpu)
{
psw_t *gpsw = &vcpu->arch.sie_block->gpsw;
psw32_t new_psw;
- u64 addr;
+ u64 addr, iaddr;
int rc;
u8 ar;

vcpu->stat.instruction_lpsw++;

+ iaddr = gpsw->addr - kvm_s390_get_ilen(vcpu);
if (gpsw->mask & PSW_MASK_PSTATE)
return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);

@@ -737,18 +738,20 @@ int kvm_s390_handle_lpsw(struct kvm_vcpu *vcpu)
gpsw->addr = new_psw.addr & ~PSW32_ADDR_AMODE;
if (!is_valid_psw(gpsw))
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
+ vcpu->arch.sie_block->gbea = iaddr;
return 0;
}

static int handle_lpswe(struct kvm_vcpu *vcpu)
{
psw_t new_psw;
- u64 addr;
+ u64 addr, iaddr;
int rc;
u8 ar;

vcpu->stat.instruction_lpswe++;

+ iaddr = vcpu->arch.sie_block->gpsw.addr - kvm_s390_get_ilen(vcpu);
if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);

@@ -761,6 +764,7 @@ static int handle_lpswe(struct kvm_vcpu *vcpu)
vcpu->arch.sie_block->gpsw = new_psw;
if (!is_valid_psw(&vcpu->arch.sie_block->gpsw))
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
+ vcpu->arch.sie_block->gbea = iaddr;
return 0;
}

--
2.51.0