Messages in this thread | | | Subject | Re: [PATCH v4 02/15] KVM: s390: reset crypto attributes for all vcpus | From | Tony Krowiak <> | Date | Tue, 17 Apr 2018 09:47:58 -0400 |
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On 04/17/2018 07:34 AM, Cornelia Huck wrote: > On Sun, 15 Apr 2018 17:22:12 -0400 > Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote: > >> Introduces a new function to reset the crypto attributes for all >> vcpus whether they are running or not. Each vcpu in KVM will >> be removed from SIE prior to resetting the crypto attributes in its >> SIE state description. After all vcpus have had their crypto attributes >> reset the vcpus will be restored to SIE. >> >> This function will be used in a later patch to set the ECA.28 >> bit in the SIE state description to enable interpretive execution of >> AP instructions. It will also be incorporated into the >> kvm_s390_vm_set_crypto(kvm) function to fix an issue whereby the crypto >> key wrapping attributes could potentially get out of synch for running >> vcpus. > So, this description leads me to think it would make sense to queue > this patch (fixing the key wrapping) independently of this series, > wouldn't it? I considered that because I figured there might be objections, but since separating them would create dependency issues I didn't see any harm in including it here. I can remove this from the explanation above and the code below and create a separate patch for the key wrapping if you'd prefer. > >> Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com> >> --- >> arch/s390/kvm/kvm-s390.c | 19 +++++++++++++------ >> arch/s390/kvm/kvm-s390.h | 14 ++++++++++++++ >> 2 files changed, 27 insertions(+), 6 deletions(-) >> >> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >> index 64c9862..d0c3518 100644 >> --- a/arch/s390/kvm/kvm-s390.c >> +++ b/arch/s390/kvm/kvm-s390.c >> @@ -791,11 +791,21 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att >> >> static void kvm_s390_vcpu_crypto_setup(struct kvm_vcpu *vcpu); >> >> -static int kvm_s390_vm_set_crypto(struct kvm *kvm, struct kvm_device_attr *attr) >> +void kvm_s390_vcpu_crypto_reset_all(struct kvm *kvm) > _reset_all() or _set_all()? Don't really care much, tbh. Then why bring it up?:) I chose _reset_all because in both places from which this is called, we are changing a crypto attribute value and are thus resetting the crypto settings for all the vcpus. > >> { >> - struct kvm_vcpu *vcpu; >> int i; >> + struct kvm_vcpu *vcpu; > I'd avoid swapping the order of the declarations. This was unintentional, I can revert it. > >> + >> + kvm_s390_vcpu_block_all(kvm); >> + >> + kvm_for_each_vcpu(i, vcpu, kvm) >> + kvm_s390_vcpu_crypto_setup(vcpu); >> and >> + kvm_s390_vcpu_unblock_all(kvm); >> +} >> + >> +static int kvm_s390_vm_set_crypto(struct kvm *kvm, struct kvm_device_attr *attr) >> +{ >> if (!test_kvm_facility(kvm, 76)) >> return -EINVAL; >> >> @@ -832,10 +842,7 @@ static int kvm_s390_vm_set_crypto(struct kvm *kvm, struct kvm_device_attr *attr) >> return -ENXIO; >> } >> >> - kvm_for_each_vcpu(i, vcpu, kvm) { >> - kvm_s390_vcpu_crypto_setup(vcpu); >> - exit_sie(vcpu); >> - } >> + kvm_s390_vcpu_crypto_reset_all(kvm); >> mutex_unlock(&kvm->lock); >> return 0; >> } >> diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h >> index 1b5621f..76324b7 100644 >> --- a/arch/s390/kvm/kvm-s390.h >> +++ b/arch/s390/kvm/kvm-s390.h >> @@ -410,4 +410,18 @@ static inline int kvm_s390_use_sca_entries(void) >> } >> void kvm_s390_reinject_machine_check(struct kvm_vcpu *vcpu, >> struct mcck_volatile_info *mcck_info); >> + >> +/** >> + * kvm_s390_vcpu_crypto_reset_all >> + * >> + * Reset the crypto attributes for each vcpu. This can be done while the vcpus >> + * are running as each vcpu will be removed from SIE before resetting the crypto >> + * attributes and restored to SIE afterward. >> + * >> + * Note: The kvm->lock mutex must be locked prior to calling this function and >> + * unlocked after it returns. > "Must be called with kvm->lock held"? Yes. The kvm->lock must be held to set the crypto attributes that will be copied to the vcpus via the kvm_s390_vcpu_crypto_reset_all() function, so it made sense to hold the lock across the entire operation.
> >> + * >> + * @kvm: the KVM guest >> + */ >> +void kvm_s390_vcpu_crypto_reset_all(struct kvm *kvm); >> #endif > Other than the nits above, looks good to me. Great! >
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