From 1ca90f4ae554034d96764577196d8dd0c3bcd05e Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Fri, 6 Mar 2026 11:25:40 +0100 Subject: [PATCH] KVM: s390: log machine checks more aggressively KVM will reinject machine checks that happen during guest activity. From a host perspective this machine check is no longer visible and even for the guest, the guest might decide to only kill a userspace program or even ignore the machine check. As this can be a disruptive event nevertheless, we should log this not only in the VM debug event (that gets lost after guest shutdown) but also on the global KVM event as well as syslog. Consolidate the logging and log with loglevel 2 and higher. Signed-off-by: Christian Borntraeger Acked-by: Janosch Frank Acked-by: Hendrik Brueckner --- arch/s390/kvm/interrupt.c | 6 ++++++ arch/s390/kvm/kvm-s390.c | 1 - arch/s390/kvm/vsie.c | 1 - 3 files changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 1a702e8ef574..7cb8ce833b62 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -2827,6 +2827,12 @@ void kvm_s390_reinject_machine_check(struct kvm_vcpu *vcpu, int rc; mci.val = mcck_info->mcic; + + /* log machine checks being reinjected on all debugs */ + VCPU_EVENT(vcpu, 2, "guest machine check %lx", mci.val); + KVM_EVENT(2, "guest machine check %lx", mci.val); + pr_info("guest machine check pid %d: %lx", current->pid, mci.val); + if (mci.sr) cr14 |= CR14_RECOVERY_SUBMASK; if (mci.dg) diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index bc7d6fa66eaf..1668580008c6 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -4634,7 +4634,6 @@ static int vcpu_post_run(struct kvm_vcpu *vcpu, int exit_reason) vcpu->run->s.regs.gprs[15] = vcpu->arch.sie_block->gg15; if (exit_reason == -EINTR) { - VCPU_EVENT(vcpu, 3, "%s", "machine check"); sie_page = container_of(vcpu->arch.sie_block, struct sie_page, sie_block); mcck_info = &sie_page->mcck_info; diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c index d249b10044eb..c0d36afd4023 100644 --- a/arch/s390/kvm/vsie.c +++ b/arch/s390/kvm/vsie.c @@ -1179,7 +1179,6 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, struc kvm_vcpu_srcu_read_lock(vcpu); if (rc == -EINTR) { - VCPU_EVENT(vcpu, 3, "%s", "machine check"); kvm_s390_reinject_machine_check(vcpu, &vsie_page->mcck_info); return 0; }