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

[Tony Krowiak <akrowiak@linux.ibm.com>]

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