Re: [PATCH v10 03/26] KVM: s390: refactor crypto initialization

Tony Krowiak
2018-09-21T23:18:57Z

On 09/12/2018 03:42 PM, Tony Krowiak wrote:
> From: Tony Krowiak <akrowiak@linux.ibm.com>
>
> This patch refactors the code that initializes and sets up the
> crypto configuration for a guest. The following changes are
> implemented via this patch:
>
> 1. Prior to the introduction of AP device virtualization, it
> was not necessary to provide guest access to the CRYCB
> unless the MSA extension 3 (MSAX3) facility was installed
> on the host system. With the introduction of AP device
> virtualization, the CRYCB must be made accessible to the
> guest if the AP instructions are installed on the host
> and are to be provided to the guest.
>
> 2. Introduces a flag indicating AP instructions executed on
> the guest shall be interpreted by the firmware. It is
> initialized to indicate AP instructions are to be
> to be interpreted and is used to set the SIE bit for
> each vcpu during vcpu setup.
>
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
> Acked-by: Janosch Frank <frankja@linux.ibm.com>
> Tested-by: Michael Mueller <mimu@linux.ibm.com>
> Tested-by: Farhan Ali <alifm@linux.ibm.com>
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
> arch/s390/include/asm/kvm_host.h | 2 +
> arch/s390/include/uapi/asm/kvm.h | 1 +
> arch/s390/kvm/kvm-s390.c | 71 ++++++++++++++++++--------------------
> 3 files changed, 37 insertions(+), 37 deletions(-)
>

(...)

> diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h
> index 9a50f02..8c23afc 100644
> --- a/arch/s390/include/uapi/asm/kvm.h
> +++ b/arch/s390/include/uapi/asm/kvm.h
> @@ -130,6 +130,7 @@ struct kvm_s390_vm_cpu_machine {
> #define KVM_S390_VM_CPU_FEAT_PFMFI 11
> #define KVM_S390_VM_CPU_FEAT_SIGPIF 12
> #define KVM_S390_VM_CPU_FEAT_KSS 13
> +#define KVM_S390_VM_CPU_FEAT_AP 14
> struct kvm_s390_vm_cpu_feat {
> __u64 feat[16];
> };
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 876fbb2..d717041 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -40,6 +40,7 @@
> #include <asm/sclp.h>
> #include <asm/cpacf.h>
> #include <asm/timex.h>
> +#include <asm/ap.h>
> #include "kvm-s390.h"
> #include "gaccess.h"
>

(...)

> @@ -2586,17 +2575,25 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
>
> static void kvm_s390_vcpu_crypto_setup(struct kvm_vcpu *vcpu)
> {
> - if (!test_kvm_facility(vcpu->kvm, 76))
> + /*
> + * If neither the AP instructions nor the MSAX3 facility are configured
> + * for the guest, there is nothing to set up.
> + */
> + if (!test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_AP) &&
> + !test_kvm_facility(vcpu->kvm, 76))
> return;
>
> + vcpu->arch.sie_block->crycbd = vcpu->kvm->arch.crypto.crycbd;
> vcpu->arch.sie_block->ecb3 &= ~(ECB3_AES | ECB3_DEA);
>
> + if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_AP))
> + vcpu->arch.sie_block->eca |= ECA_APIE;
> +
> + /* Set up protected key support */
> if (vcpu->kvm->arch.crypto.aes_kw)
> vcpu->arch.sie_block->ecb3 |= ECB3_AES;
> if (vcpu->kvm->arch.crypto.dea_kw)
> vcpu->arch.sie_block->ecb3 |= ECB3_DEA;
> -
> - vcpu->arch.sie_block->crycbd = vcpu->kvm->arch.crypto.crycbd;
> }
>
> void kvm_s390_vcpu_unsetup_cmma(struct kvm_vcpu *vcpu)
>

The fixup! patch below modifies this patch (03/26) to illustrate how

David's recommendation will be implemented for v11 of the series. It

is one of three fixup! patches (the other two are in responses to
11/26
and 25/26) included to generate discussion in v10 rather than

waiting until v11 for comments.

-----------------------------------8<-----------------------------------

From: Tony Krowiak <akrowiak@linux.ibm.com>
Date: Thu, 20 Sep 2018 12:26:08 -0400
Subject: [FIXUP v10] fixup!: KVM: s390: refactor crypto initialization

---
arch/s390/include/asm/kvm_host.h | 1 +
arch/s390/include/uapi/asm/kvm.h | 1 -
arch/s390/kvm/kvm-s390.c | 9 ++++-----
3 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/s390/include/asm/kvm_host.h
b/arch/s390/include/asm/kvm_host.h
index 423cce7..79fa0a3 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -718,6 +718,7 @@ struct kvm_s390_crypto {
__u32 crycbd;
__u8 aes_kw;
__u8 dea_kw;
+ __u8 apie;
};

#define APCB0_MASK_SIZE 1
diff --git a/arch/s390/include/uapi/asm/kvm.h
b/arch/s390/include/uapi/asm/kvm.h
index 8c23afc..9a50f02 100644
--- a/arch/s390/include/uapi/asm/kvm.h
+++ b/arch/s390/include/uapi/asm/kvm.h
@@ -130,7 +130,6 @@ struct kvm_s390_vm_cpu_machine {
#define KVM_S390_VM_CPU_FEAT_PFMFI 11
#define KVM_S390_VM_CPU_FEAT_SIGPIF 12
#define KVM_S390_VM_CPU_FEAT_KSS 13
-#define KVM_S390_VM_CPU_FEAT_AP 14
struct kvm_s390_vm_cpu_feat {
__u64 feat[16];
};
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index d717041..ae4769b 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2576,17 +2576,16 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
static void kvm_s390_vcpu_crypto_setup(struct kvm_vcpu *vcpu)
{
/*
- * If neither the AP instructions nor the MSAX3 facility are configured
- * for the guest, there is nothing to set up.
+ * If the AP instructions are not available and the MSAX3 facility
+ * is not configured for the guest, there is nothing to set up.
*/
- if (!test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_AP) &&
- !test_kvm_facility(vcpu->kvm, 76))
+ if (!ap_instructions_available() && !test_kvm_facility(vcpu->kvm, 76))
return;

vcpu->arch.sie_block->crycbd = vcpu->kvm->arch.crypto.crycbd;
vcpu->arch.sie_block->ecb3 &= ~(ECB3_AES | ECB3_DEA);

- if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_AP))
+ if (vcpu->kvm->arch.crypto.apie)
vcpu->arch.sie_block->eca |= ECA_APIE;

/* Set up protected key support */
--
1.7.1