[PATCH for 5.1 and older] KVM: s390: Do not report unusabled IDs via KVM_CAP_MAX_VCPU_ID

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Thomas Huth <thuth@xxxxxxxxxx>

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 <drjones@xxxxxxxxxx>
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
Message-Id: <20190523164309.13345-9-thuth@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
[backport to 5.1 and older]
---
 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(-)

diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 6d0517ac18e50..0369f26ab96d6 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -1122,6 +1122,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	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;
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 8885377ec3e0c..d2e800e27f036 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -650,6 +650,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	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;
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 4638303ba6a85..c4180ecfbb2a4 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -507,6 +507,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		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;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6b8575c547eed..efc8adf7ca0e0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3090,6 +3090,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	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;
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index f412ebc906100..8e2a5eb38bc07 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -224,6 +224,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	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;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2b2a460c62520..48c549a884869 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3062,8 +3062,6 @@ static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
 	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;
 	}
-- 
2.21.0




[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux