On 02/28/2018 06:58 AM, David Hildenbrand wrote:
On 28.02.2018 12:40, Christian Borntraeger wrote:
On 02/28/2018 10:48 AM, David Hildenbrand wrote:
On 27.02.2018 15:28, Tony Krowiak wrote:
Introduces a new CPU model feature and two CPU model
facilities to support AP virtualization for KVM guests.
CPU model feature:
The KVM_S390_VM_CPU_FEAT_AP feature indicates that the
AP facilities are installed on the KVM guest. This
feature will be enabled by the kernel only if the AP
facilities are installed on the linux host. This feature
must be specifically turned on for the KVM guest from
userspace to allow guest access to AP devices installed
on the linux host.
CPU model facilities:
1. AP Query Configuration Information (QCI) facility is installed.
This is indicated by setting facilities bit 12 for
the guest. The kernel will not enable this facility
for the guest if it is not set on the host. This facility
must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP
feature is not installed.
2. AP Facilities Test facility (APFT) is installed.
This is indicated by setting facilities bit 15 for
the guest. The kernel will not enable this facility for
the guest if it is not set on the host. This facility
must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP
feature is not installed.
Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Reviewed-by: Halil Pasic <pasic@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx>
---
arch/s390/include/uapi/asm/kvm.h | 1 +
arch/s390/kvm/kvm-s390.c | 4 ++++
arch/s390/tools/gen_facilities.c | 2 ++
3 files changed, 7 insertions(+), 0 deletions(-)
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 de1e299..c68ca86 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -347,6 +347,10 @@ static void kvm_s390_cpu_feat_init(void)
if (MACHINE_HAS_ESOP)
allow_cpu_feat(KVM_S390_VM_CPU_FEAT_ESOP);
+
+ if (ap_instructions_installed()) /* AP instructions installed on host */
+ allow_cpu_feat(KVM_S390_VM_CPU_FEAT_AP);
Don't we have a SIE specific AP feature? So is it true, that once we
have AP instructions, we are allowed to use them for SIE? Isn't there a
"AP interpretation facility" or anything like that? (that unlocks ECA_APIE)
This seems to be coupled to the AP facility and there is no facility or scp bit.
AP is too old to have that (predates STFLE)
Interesting, so we (I :) ) didn't implement vSIE support back then
because we never indicated the AP facility (sensed by executing the
instruction) to the guest.
So ECA_APIE can be used when we sense the AP facility. Thanks!
All true.
