Re: [PATCH v9 07/22] KVM: s390: refactor crypto initialization
From: Tony Krowiak
Date: Mon Aug 20 2018 - 16:34:05 EST
On 08/20/2018 12:41 PM, David Hildenbrand wrote:
On 13.08.2018 23:48, Tony Krowiak wrote:
From: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Reviewed-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
Acked-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Acked-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
Tested-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
Tested-by: Farhan Ali <alifm@xxxxxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
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))
I think this can just stay "test_kvm_facility(vcpu->kvm, 76)", and the
comment should be changed to
"If neither the AP instructions nor the MSAX3 facility are configured
for the guest, there is nothing to set up."
Or am I missing something important here?
No, you're not missing anything, it can be test_kvm_facility() and I'm
more than happy to change the comment.
After the CPU has been created, both feature can no longer change. The
only thing that might change is kvm->arch.crypto.aes_kw/dea_kw but only
with 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 (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;
As this feature can never flip, clearing the flag is not necessary.
Okay.
+ 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;
+ }
As the feature can never change, and aes_kw/dea_kw are only set to 1 in
case we have test_kvm_facility(vcpu->kvm, 76), this change is not needed.
I think this function can be pretty much left alone. Just add the
KVM_S390_VM_CPU_FEAT_AP handling.
I disagree, what about the case where the KVM_S390_VM_CPU_FEAT_AP is
configured for the guest but the MSAX3 facility (76) is not?
}
void kvm_s390_vcpu_unsetup_cmma(struct kvm_vcpu *vcpu)