Messages in this thread | | | Date | Mon, 24 Jan 2022 15:24:51 +0100 | Subject | Re: [PATCH v2 17/30] KVM: s390: mechanism to enable guest zPCI Interpretation | From | Pierre Morel <> |
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On 1/14/22 21:31, Matthew Rosato wrote: > The guest must have access to certain facilities in order to allow > interpretive execution of zPCI instructions and adapter event > notifications. However, there are some cases where a guest might > disable interpretation -- provide a mechanism via which we can defer > enabling the associated zPCI interpretation facilities until the guest > indicates it wishes to use them. > > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> > --- > arch/s390/include/asm/kvm_host.h | 4 ++++ > arch/s390/kvm/kvm-s390.c | 40 ++++++++++++++++++++++++++++++++ > arch/s390/kvm/kvm-s390.h | 10 ++++++++ > 3 files changed, 54 insertions(+) > > diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h > index 3f147b8d050b..38982c1de413 100644 > --- a/arch/s390/include/asm/kvm_host.h > +++ b/arch/s390/include/asm/kvm_host.h > @@ -252,7 +252,10 @@ struct kvm_s390_sie_block { > #define ECB2_IEP 0x20 > #define ECB2_PFMFI 0x08 > #define ECB2_ESCA 0x04 > +#define ECB2_ZPCI_LSI 0x02 > __u8 ecb2; /* 0x0062 */ > +#define ECB3_AISI 0x20 > +#define ECB3_AISII 0x10 > #define ECB3_DEA 0x08 > #define ECB3_AES 0x04 > #define ECB3_RI 0x01 > @@ -938,6 +941,7 @@ struct kvm_arch{ > int use_cmma; > int use_pfmfi; > int use_skf; > + int use_zpci_interp; > int user_cpu_state_ctrl; > int user_sigp; > int user_stsi; > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index ab8b56deed11..b6c32fc3b272 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -1029,6 +1029,44 @@ static int kvm_s390_vm_set_crypto(struct kvm *kvm, struct kvm_device_attr *attr) > return 0; > } > > +static void kvm_s390_vcpu_pci_setup(struct kvm_vcpu *vcpu) > +{ > + /* Only set the ECB bits after guest requests zPCI interpretation */ > + if (!vcpu->kvm->arch.use_zpci_interp) > + return; > + > + vcpu->arch.sie_block->ecb2 |= ECB2_ZPCI_LSI; > + vcpu->arch.sie_block->ecb3 |= ECB3_AISII + ECB3_AISI;
As far as I understood, the interpretation is only possible if a gisa designation is associated with the PCI function via CLP enable.
Why do we setup the SIE ECB only when the guest requests for interpretation and not systematically in vcpu_setup?
If ECB2_ZPCI_LSI, ECB3_AISII or ECB3_AISI have an effect when the gisa designation is not specified shouldn't we have a way to clear these bits?
> +} > + > +void kvm_s390_vcpu_pci_enable_interp(struct kvm *kvm) > +{ > + struct kvm_vcpu *vcpu; > + int i; > + > + /* > + * If host is configured for PCI and the necessary facilities are > + * available, turn on interpretation for the life of this guest > + */ > + if (!IS_ENABLED(CONFIG_PCI) || !sclp.has_zpci_lsi || !sclp.has_aisii || > + !sclp.has_aeni || !sclp.has_aisi) > + return; > + > + mutex_lock(&kvm->lock); > + > + kvm->arch.use_zpci_interp = 1; > + > + kvm_s390_vcpu_block_all(kvm); > + > + kvm_for_each_vcpu(i, vcpu, kvm) { > + kvm_s390_vcpu_pci_setup(vcpu); > + kvm_s390_sync_request(KVM_REQ_VSIE_RESTART, vcpu); > + } > + > + kvm_s390_vcpu_unblock_all(kvm); > + mutex_unlock(&kvm->lock); > +} > + > static void kvm_s390_sync_request_broadcast(struct kvm *kvm, int req) > { > int cx; > @@ -3282,6 +3320,8 @@ static int kvm_s390_vcpu_setup(struct kvm_vcpu *vcpu) > > kvm_s390_vcpu_crypto_setup(vcpu); > > + kvm_s390_vcpu_pci_setup(vcpu); > + > mutex_lock(&vcpu->kvm->lock); > if (kvm_s390_pv_is_protected(vcpu->kvm)) { > rc = kvm_s390_pv_create_cpu(vcpu, &uvrc, &uvrrc); > diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h > index c07a050d757d..a2eccb8b977e 100644 > --- a/arch/s390/kvm/kvm-s390.h > +++ b/arch/s390/kvm/kvm-s390.h > @@ -481,6 +481,16 @@ void kvm_s390_reinject_machine_check(struct kvm_vcpu *vcpu, > */ > void kvm_s390_vcpu_crypto_reset_all(struct kvm *kvm); > > +/** > + * kvm_s390_vcpu_pci_enable_interp > + * > + * Set the associated PCI attributes for each vcpu to allow for zPCI Load/Store > + * interpretation as well as adapter interruption forwarding. > + * > + * @kvm: the KVM guest > + */ > +void kvm_s390_vcpu_pci_enable_interp(struct kvm *kvm); > + > /** > * diag9c_forwarding_hz > * >
-- Pierre Morel IBM Lab Boeblingen
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