From 7119decf47d9867266459615be502e5d2cecedba Mon Sep 17 00:00:00 2001 From: Janis Schoetterl-Glausch Date: Tue, 29 Jun 2021 10:55:30 +0200 Subject: KVM: s390: Enable specification exception interpretation When this feature is enabled the hardware is free to interpret specification exceptions generated by the guest, instead of causing program interruption interceptions. This benefits (test) programs that generate a lot of specification exceptions (roughly 4x increase in exceptions/sec). Interceptions will occur as before if ICTL_PINT is set, i.e. if guest debug is enabled. There is no indication if this feature is available or not and the hardware is free to interpret or not. So we can simply set this bit and if the hardware ignores it we fall back to intercept 8 handling. Signed-off-by: Janis Schoetterl-Glausch Link: https://lore.kernel.org/linux-s390/20210706114714.3936825-1-scgl@linux.ibm.com/ Reviewed-by: David Hildenbrand Reviewed-by: Christian Borntraeger Signed-off-by: Christian Borntraeger --- arch/s390/include/asm/kvm_host.h | 1 + arch/s390/kvm/kvm-s390.c | 2 ++ arch/s390/kvm/vsie.c | 2 ++ 3 files changed, 5 insertions(+) (limited to 'arch') diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 8925f3969478..118d5450c523 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -244,6 +244,7 @@ struct kvm_s390_sie_block { __u8 fpf; /* 0x0060 */ #define ECB_GS 0x40 #define ECB_TE 0x10 +#define ECB_SPECI 0x08 #define ECB_SRSI 0x04 #define ECB_HOSTPROTINT 0x02 __u8 ecb; /* 0x0061 */ diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index f72f361d39dd..5b45c83ced21 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -3180,6 +3180,8 @@ static int kvm_s390_vcpu_setup(struct kvm_vcpu *vcpu) vcpu->arch.sie_block->ecb |= ECB_SRSI; if (test_kvm_facility(vcpu->kvm, 73)) vcpu->arch.sie_block->ecb |= ECB_TE; + if (!kvm_is_ucontrol(vcpu->kvm)) + vcpu->arch.sie_block->ecb |= ECB_SPECI; if (test_kvm_facility(vcpu->kvm, 8) && vcpu->kvm->arch.use_pfmfi) vcpu->arch.sie_block->ecb2 |= ECB2_PFMFI; diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c index 4002a24bc43a..acda4b6fc851 100644 --- a/arch/s390/kvm/vsie.c +++ b/arch/s390/kvm/vsie.c @@ -510,6 +510,8 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) prefix_unmapped(vsie_page); scb_s->ecb |= ECB_TE; } + /* specification exception interpretation */ + scb_s->ecb |= scb_o->ecb & ECB_SPECI; /* branch prediction */ if (test_kvm_facility(vcpu->kvm, 82)) scb_s->fpf |= scb_o->fpf & FPF_BPBC; -- cgit From a3e03bc1368c1bc16e19b001fc96dc7430573cc8 Mon Sep 17 00:00:00 2001 From: Halil Pasic Date: Fri, 27 Aug 2021 14:54:29 +0200 Subject: KVM: s390: index kvm->arch.idle_mask by vcpu_idx MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit While in practice vcpu->vcpu_idx == vcpu->vcp_id is often true, it may not always be, and we must not rely on this. Reason is that KVM decides the vcpu_idx, userspace decides the vcpu_id, thus the two might not match. Currently kvm->arch.idle_mask is indexed by vcpu_id, which implies that code like for_each_set_bit(vcpu_id, kvm->arch.idle_mask, online_vcpus) { vcpu = kvm_get_vcpu(kvm, vcpu_id); do_stuff(vcpu); } is not legit. Reason is that kvm_get_vcpu expects an vcpu_idx, not an vcpu_id. The trouble is, we do actually use kvm->arch.idle_mask like this. To fix this problem we have two options. Either use kvm_get_vcpu_by_id(vcpu_id), which would loop to find the right vcpu_id, or switch to indexing via vcpu_idx. The latter is preferable for obvious reasons. Let us make switch from indexing kvm->arch.idle_mask by vcpu_id to indexing it by vcpu_idx. To keep gisa_int.kicked_mask indexed by the same index as idle_mask lets make the same change for it as well. Fixes: 1ee0bc559dc3 ("KVM: s390: get rid of local_int array") Signed-off-by: Halil Pasic Reviewed-by: Christian Bornträger Reviewed-by: Claudio Imbrenda Cc: # 3.15+ Link: https://lore.kernel.org/r/20210827125429.1912577-1-pasic@linux.ibm.com Signed-off-by: Christian Borntraeger --- arch/s390/include/asm/kvm_host.h | 1 + arch/s390/kvm/interrupt.c | 12 ++++++------ arch/s390/kvm/kvm-s390.c | 2 +- arch/s390/kvm/kvm-s390.h | 2 +- 4 files changed, 9 insertions(+), 8 deletions(-) (limited to 'arch') diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 118d5450c523..611f18ecde91 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -963,6 +963,7 @@ struct kvm_arch{ atomic64_t cmma_dirty_pages; /* subset of available cpu features enabled by user space */ DECLARE_BITMAP(cpu_feat, KVM_S390_VM_CPU_FEAT_NR_BITS); + /* indexed by vcpu_idx */ DECLARE_BITMAP(idle_mask, KVM_MAX_VCPUS); struct kvm_s390_gisa_interrupt gisa_int; struct kvm_s390_pv pv; diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index d548d60caed2..16256e17a544 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -419,13 +419,13 @@ static unsigned long deliverable_irqs(struct kvm_vcpu *vcpu) static void __set_cpu_idle(struct kvm_vcpu *vcpu) { kvm_s390_set_cpuflags(vcpu, CPUSTAT_WAIT); - set_bit(vcpu->vcpu_id, vcpu->kvm->arch.idle_mask); + set_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.idle_mask); } static void __unset_cpu_idle(struct kvm_vcpu *vcpu) { kvm_s390_clear_cpuflags(vcpu, CPUSTAT_WAIT); - clear_bit(vcpu->vcpu_id, vcpu->kvm->arch.idle_mask); + clear_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.idle_mask); } static void __reset_intercept_indicators(struct kvm_vcpu *vcpu) @@ -3050,18 +3050,18 @@ int kvm_s390_get_irq_state(struct kvm_vcpu *vcpu, __u8 __user *buf, int len) static void __airqs_kick_single_vcpu(struct kvm *kvm, u8 deliverable_mask) { - int vcpu_id, online_vcpus = atomic_read(&kvm->online_vcpus); + int vcpu_idx, online_vcpus = atomic_read(&kvm->online_vcpus); struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int; struct kvm_vcpu *vcpu; - for_each_set_bit(vcpu_id, kvm->arch.idle_mask, online_vcpus) { - vcpu = kvm_get_vcpu(kvm, vcpu_id); + for_each_set_bit(vcpu_idx, kvm->arch.idle_mask, online_vcpus) { + vcpu = kvm_get_vcpu(kvm, vcpu_idx); if (psw_ioint_disabled(vcpu)) continue; deliverable_mask &= (u8)(vcpu->arch.sie_block->gcr[6] >> 24); if (deliverable_mask) { /* lately kicked but not yet running */ - if (test_and_set_bit(vcpu_id, gi->kicked_mask)) + if (test_and_set_bit(vcpu_idx, gi->kicked_mask)) return; kvm_s390_vcpu_wakeup(vcpu); return; diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 5b45c83ced21..e144c8046ceb 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -4026,7 +4026,7 @@ static int vcpu_pre_run(struct kvm_vcpu *vcpu) kvm_s390_patch_guest_per_regs(vcpu); } - clear_bit(vcpu->vcpu_id, vcpu->kvm->arch.gisa_int.kicked_mask); + clear_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.gisa_int.kicked_mask); vcpu->arch.sie_block->icptcode = 0; cpuflags = atomic_read(&vcpu->arch.sie_block->cpuflags); diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h index 9fad25109b0d..ecd741ee3276 100644 --- a/arch/s390/kvm/kvm-s390.h +++ b/arch/s390/kvm/kvm-s390.h @@ -79,7 +79,7 @@ static inline int is_vcpu_stopped(struct kvm_vcpu *vcpu) static inline int is_vcpu_idle(struct kvm_vcpu *vcpu) { - return test_bit(vcpu->vcpu_id, vcpu->kvm->arch.idle_mask); + return test_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.idle_mask); } static inline int kvm_is_ucontrol(struct kvm *kvm) -- cgit