[PATCH 3/3] s390/kvm: set host program identifier

[PATCH 3/3] s390/kvm: set host program identifier

[Collin Walling]

A host program identifier (HPID) provides information regarding the underlying
host environment. A level-2 (VM) guest will have an HPID denoting Linux/KVM,
which is set during VCPU setup. A level-3 (VM on a VM) and beyond guest will
have an HPID denoting VSIE, which is set (and is overwritten) during shadowing
of the SCB.

Signed-off-by: Collin Walling <walling@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
---
 arch/s390/include/asm/kvm_host.h | 6 +++++-
 arch/s390/kvm/kvm-s390.c         | 2 ++
 arch/s390/kvm/vsie.c             | 2 ++
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index fabeb32..8c877f5 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -238,7 +238,11 @@ struct kvm_s390_sie_block {
 	psw_t	gpsw;			/* 0x0090 */
 	__u64	gg14;			/* 0x00a0 */
 	__u64	gg15;			/* 0x00a8 */
-	__u8	reservedb0[20];		/* 0x00b0 */
+	__u8	reservedb0[8];		/* 0x00b0 */
+#define HPID_KVM	0x4
+#define HPID_VSIE	0x5
+	__u8	hpid;			/* 0x00b8 */
+	__u8	reservedb9[11];		/* 0x00b9 */
 	__u16	extcpuaddr;		/* 0x00c4 */
 	__u16	eic;			/* 0x00c6 */
 	__u32	reservedc8;		/* 0x00c8 */
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 678c9cb..aac8a22 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2773,6 +2773,8 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
 	hrtimer_init(&vcpu->arch.ckc_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	vcpu->arch.ckc_timer.function = kvm_s390_idle_wakeup;
 
+	vcpu->arch.sie_block->hpid = HPID_KVM;
+
 	kvm_s390_vcpu_crypto_setup(vcpu);
 
 	return rc;
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index 63844b9..2b701b4 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -382,6 +382,8 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 	if (test_kvm_facility(vcpu->kvm, 156))
 		scb_s->ecd |= scb_o->ecd & ECD_ETOKENF;
 
+	scb_s->hpid = HPID_VSIE;
+
 	prepare_ibc(vcpu, vsie_page);
 	rc = shadow_crycb(vcpu, vsie_page);
 out:
-- 
2.7.4

Re: [PATCH 3/3] s390/kvm: set host program identifier

[David Hildenbrand]

Am 17.09.18 um 09:54 schrieb Christian Borntraeger:
> 
> 
> On 09/17/2018 09:46 AM, David Hildenbrand wrote:
>> Am 04.09.18 um 13:16 schrieb Christian Borntraeger:
>>> Changed subject to KVM: s390: .... and modified the commit message.
>>>
>>> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
>>>
>>> Patch 3 applied and scheduled for >4.19 (kvm/next).
>>>
>>
>> Christian, is it okay to set this field even without HW support?
>>
>> (I slightly remember that certain reserved fields should remain
>> untouched if there is no HW support for them, maybe I am wrong or this
>> does not apply here)
> 
> Yes, there is no scp bit for this, it can be set unconditionally.
> 

Thanks, feel free to add

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 

Thanks,

David / dhildenb