Re: [RFC 02/19] KVM: s390: refactor crypto initialization

Christian Borntraeger
2017-11-02T12:41:18Z

On 10/13/2017 07:38 PM, Tony Krowiak wrote:
> This patch introduces the following changes to crypto initialization.
>
> * For key management operations support, the crypto control block
> (CRYCB) referenced by the KVM guest's SIE state description is
> formatted only if the Message-Security-Assist (MSA) extension 3
> facility is installed (STFLE.76 is set). Virtualization of AP
> facilities, however; requires that a CRYCB of the appropriate
> format be made available to SIE regardless of the value of STFLE.76.
>
> * The Execution Controls A (ECA) field bit 28 in the SIE block needs
> to be set to enable interpretive execution mode of adjunct processor (AP)
> instructions.

We should fence setting ECA to cases where we have virtualization capability
for crypto. In addition we need to bind this somehow to the CPU model, so
I guess we need to add some CRYPTO feature e.g. add KVM_S390_VM_CPU_FEAT_AP to the
list of know features
(see arch/s390/include/uapi/asm/kvm.h)
---snip---
#define KVM_S390_VM_CPU_FEAT_ESOP 0
#define KVM_S390_VM_CPU_FEAT_SIEF2 1
#define KVM_S390_VM_CPU_FEAT_64BSCAO 2
#define KVM_S390_VM_CPU_FEAT_SIIF 3
#define KVM_S390_VM_CPU_FEAT_GPERE 4
#define KVM_S390_VM_CPU_FEAT_GSLS 5
#define KVM_S390_VM_CPU_FEAT_IB 6
#define KVM_S390_VM_CPU_FEAT_CEI 7
#define KVM_S390_VM_CPU_FEAT_IBS 8
#define KVM_S390_VM_CPU_FEAT_SKEY 9
#define KVM_S390_VM_CPU_FEAT_CMMA 10
#define KVM_S390_VM_CPU_FEAT_PFMFI 11
#define KVM_S390_VM_CPU_FEAT_SIGPIF 12
#define KVM_S390_VM_CPU_FEAT_KSS 13
---snip---

I will try to find out a way to properly detect that.

>
> Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com>
> ---
> arch/s390/include/asm/kvm_host.h | 1 +
> arch/s390/kvm/kvm-s390.c | 17 +++++++++++++----
> 2 files changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
> index 50a6b25..5683f18 100644
> --- a/arch/s390/include/asm/kvm_host.h
> +++ b/arch/s390/include/asm/kvm_host.h
> @@ -188,6 +188,7 @@ struct kvm_s390_sie_block {
> #define ECA_MVPGI 0x01000000
> #define ECA_VX 0x00020000
> #define ECA_PROTEXCI 0x00002000
> +#define ECA_AP 0x00000008
> #define ECA_SII 0x00000001
> __u32 eca; /* 0x004c */
> #define ICPT_INST 0x04
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 40d0a1a..e57fc9b 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -1819,7 +1819,9 @@ static void kvm_s390_set_crycb_format(struct kvm *kvm)
> {
> kvm->arch.crypto.crycbd = (__u32)(unsigned long) kvm->arch.crypto.crycb;
>
> - if (kvm_s390_apxa_installed())
> + if (!test_kvm_facility(kvm, 76))
> + kvm->arch.crypto.crycbd &= ~(CRYCB_FORMAT2); /* format 0 */
> + else if (kvm_s390_apxa_installed())
> kvm->arch.crypto.crycbd |= CRYCB_FORMAT2;
> else
> kvm->arch.crypto.crycbd |= CRYCB_FORMAT1;
> @@ -1836,12 +1838,12 @@ static u64 kvm_s390_get_initial_cpuid(void)
>
> static void kvm_s390_crypto_init(struct kvm *kvm)
> {
> - if (!test_kvm_facility(kvm, 76))
> - return;
> -
> kvm->arch.crypto.crycb = &kvm->arch.sie_page2->crycb;
> kvm_s390_set_crycb_format(kvm);
>
> + if (!test_kvm_facility(kvm, 76))
> + return;
> +
> /* Enable AES/DEA protected key functions by default */
> kvm->arch.crypto.aes_kw = 1;
> kvm->arch.crypto.dea_kw = 1;
> @@ -2366,8 +2368,15 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
> vcpu->arch.enabled_gmap = vcpu->arch.gmap;
> }
>
> +static void kvm_s390_vcpu_set_crypto_exec_mode(struct kvm_vcpu *vcpu)
> +{
> + vcpu->arch.sie_block->eca |= ECA_AP;
> +}
> +
> static void kvm_s390_vcpu_crypto_setup(struct kvm_vcpu *vcpu)
> {
> + kvm_s390_vcpu_set_crypto_exec_mode(vcpu);
> +
> if (!test_kvm_facility(vcpu->kvm, 76))
> return;
>