From: Thomas Huth <th...@redhat.com>
commit a86cb413f4bf273a9d341a3ab2c2ca44e12eb317 upstream.
KVM_CAP_MAX_VCPU_ID is currently always reporting KVM_MAX_VCPU_ID on all
architectures. However, on s390x, the amount of usable CPUs is determined
during runtime - it is depending on the features of the machine the code
is running on. Since we are using the vcpu_id as an index into the SCA
structures that are defined by the hardware (see e.g. the sca_add_vcpu()
function), it is not only the amount of CPUs that is limited by the hard-
ware, but also the range of IDs that we can use.
Thus KVM_CAP_MAX_VCPU_ID must be determined during runtime on s390x, too.
So the handling of KVM_CAP_MAX_VCPU_ID has to be moved from the common
code into the architecture specific code, and on s390x we have to return
the same value here as for KVM_CAP_MAX_VCPUS.
This problem has been discovered with the kvm_create_max_vcpus selftest.
With this change applied, the selftest now passes on s390x, too.
Reviewed-by: Andrew Jones <drjo...@redhat.com>
Reviewed-by: Cornelia Huck <coh...@redhat.com>
Reviewed-by: David Hildenbrand <da...@redhat.com>
Signed-off-by: Thomas Huth <th...@redhat.com>
Message-Id: <20190523164309.13345-9-th...@redhat.com>
Cc: sta...@vger.kernel.org
Signed-off-by: Christian Borntraeger <borntrae...@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/mips/kvm/mips.c | 3 +++
arch/powerpc/kvm/powerpc.c | 3 +++
arch/s390/kvm/kvm-s390.c | 1 +
arch/x86/kvm/x86.c | 3 +++
virt/kvm/arm/arm.c | 3 +++
virt/kvm/kvm_main.c | 2 --
6 files changed, 13 insertions(+), 2 deletions(-)
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -1099,6 +1099,9 @@ int kvm_vm_ioctl_check_extension(struct
case KVM_CAP_MAX_VCPUS:
r = KVM_MAX_VCPUS;
break;
+ case KVM_CAP_MAX_VCPU_ID:
+ r = KVM_MAX_VCPU_ID;
+ break;
case KVM_CAP_MIPS_FPU:
/* We don't handle systems with inconsistent cpu_has_fpu */
r = !!raw_cpu_has_fpu;
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -632,6 +632,9 @@ int kvm_vm_ioctl_check_extension(struct
case KVM_CAP_MAX_VCPUS:
r = KVM_MAX_VCPUS;
break;
+ case KVM_CAP_MAX_VCPU_ID:
+ r = KVM_MAX_VCPU_ID;
+ break;
#ifdef CONFIG_PPC_BOOK3S_64
case KVM_CAP_PPC_GET_SMMU_INFO:
r = 1;
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -489,6 +489,7 @@ int kvm_vm_ioctl_check_extension(struct
break;
case KVM_CAP_NR_VCPUS:
case KVM_CAP_MAX_VCPUS:
+ case KVM_CAP_MAX_VCPU_ID:
r = KVM_S390_BSCA_CPU_SLOTS;
if (!kvm_s390_use_sca_entries())
r = KVM_MAX_VCPUS;
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2987,6 +2987,9 @@ int kvm_vm_ioctl_check_extension(struct
case KVM_CAP_MAX_VCPUS:
r = KVM_MAX_VCPUS;
break;
+ case KVM_CAP_MAX_VCPU_ID:
+ r = KVM_MAX_VCPU_ID;
+ break;
case KVM_CAP_NR_MEMSLOTS:
r = KVM_USER_MEM_SLOTS;
break;
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -223,6 +223,9 @@ int kvm_vm_ioctl_check_extension(struct
case KVM_CAP_MAX_VCPUS:
r = KVM_MAX_VCPUS;
break;
+ case KVM_CAP_MAX_VCPU_ID:
+ r = KVM_MAX_VCPU_ID;
+ break;
case KVM_CAP_NR_MEMSLOTS:
r = KVM_USER_MEM_SLOTS;
break;
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2965,8 +2965,6 @@ static long kvm_vm_ioctl_check_extension
case KVM_CAP_MULTI_ADDRESS_SPACE:
return KVM_ADDRESS_SPACE_NUM;
#endif
- case KVM_CAP_MAX_VCPU_ID:
- return KVM_MAX_VCPU_ID;
default:
break;
}
