[PATCH v9 07/22] KVM: s390: refactor crypto initialization

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

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         |   81 +++++++++++++++++++-------------------
 3 files changed, 44 insertions(+), 40 deletions(-)

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index af39561..4a739d4 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -187,6 +187,7 @@ struct kvm_s390_sie_block {
 #define ECA_AIV		0x00200000
 #define ECA_VX		0x00020000
 #define ECA_PROTEXCI	0x00002000
+#define ECA_APIE	0x00000008
 #define ECA_SII		0x00000001
 	__u32	eca;			/* 0x004c */
 #define ICPT_INST	0x04
@@ -256,6 +257,7 @@ struct kvm_s390_sie_block {
 	__u8	reservede4[4];		/* 0x00e4 */
 	__u64	tecmc;			/* 0x00e8 */
 	__u8	reservedf0[12];		/* 0x00f0 */
+#define CRYCB_FORMAT_MASK 0x00000003
 #define CRYCB_FORMAT1 0x00000001
 #define CRYCB_FORMAT2 0x00000003
 	__u32	crycbd;			/* 0x00fc */
diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h
index 4cdaa55..a580dec 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 19f4f44..f7de123 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"
 
@@ -1881,49 +1882,37 @@ long kvm_arch_vm_ioctl(struct file *filp,
 	return r;
 }
 
-static int kvm_s390_query_ap_config(u8 *config)
-{
-	u32 fcn_code = 0x04000000UL;
-	u32 cc = 0;
-
-	memset(config, 0, 128);
-	asm volatile(
-		"lgr 0,%1\n"
-		"lgr 2,%2\n"
-		".long 0xb2af0000\n"		/* PQAP(QCI) */
-		"0: ipm %0\n"
-		"srl %0,28\n"
-		"1:\n"
-		EX_TABLE(0b, 1b)
-		: "+r" (cc)
-		: "r" (fcn_code), "r" (config)
-		: "cc", "0", "2", "memory"
-	);
-
-	return cc;
-}
-
 static int kvm_s390_apxa_installed(void)
 {
-	u8 config[128];
-	int cc;
+	struct ap_config_info info;
 
-	if (test_facility(12)) {
-		cc = kvm_s390_query_ap_config(config);
-
-		if (cc)
-			pr_err("PQAP(QCI) failed with cc=%d", cc);
-		else
-			return config[0] & 0x40;
+	if (ap_instructions_available()) {
+		if (ap_qci(&info) == 0)
+			return info.apxa;
 	}
 
 	return 0;
 }
 
+/*
+ * The format of the crypto control block (CRYCB) is specified in the 3 low
+ * order bits of the CRYCB designation (CRYCBD) field as follows:
+ * Format 0: Neither the message security assist extension 3 (MSAX3) nor the
+ *	     AP extended addressing (APXA) facility are installed.
+ * Format 1: The APXA facility is not installed but the MSAX3 facility is.
+ * Format 2: Both the APXA and MSAX3 facilities are installed
+ */
 static void kvm_s390_set_crycb_format(struct kvm *kvm)
 {
 	kvm->arch.crypto.crycbd = (__u32)(unsigned long) kvm->arch.crypto.crycb;
 
+	/* Clear the CRYCB format bits - i.e., set format 0 by default */
+	kvm->arch.crypto.crycbd &= ~(CRYCB_FORMAT_MASK);
+
+	/* Check whether MSAX3 is installed */
+	if (!test_kvm_facility(kvm, 76))
+		return;
+
 	if (kvm_s390_apxa_installed())
 		kvm->arch.crypto.crycbd |= CRYCB_FORMAT2;
 	else
@@ -1941,12 +1930,12 @@ 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;
@@ -2474,17 +2463,29 @@ 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 installed
+	 * on the host, then there is no need for a CRYCB in SIE because they
+	 * will not be installed on the guest either.
+	 */
+	if (!test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_AP) &&
+	    !test_facility(76))
 		return;
 
+	vcpu->arch.sie_block->crycbd = vcpu->kvm->arch.crypto.crycbd;
 	vcpu->arch.sie_block->ecb3 &= ~(ECB3_AES | ECB3_DEA);
 
-	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->eca &= ~ECA_APIE;
+	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_AP))
+		vcpu->arch.sie_block->eca |= ECA_APIE;
 
-	vcpu->arch.sie_block->crycbd = vcpu->kvm->arch.crypto.crycbd;
+	/* If MSAX3 is installed on the guest, set up protected key support */
+	if (test_kvm_facility(vcpu->kvm, 76)) {
+		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;
+	}
 }
 
 void kvm_s390_vcpu_unsetup_cmma(struct kvm_vcpu *vcpu)
-- 
1.7.1