On arm64, the maximum number of vcpus is constrained by the type
of interrupt controller that has been selected (GICv2 imposes a
limit of 8 vcpus, while GICv3 currently has a limit of 512).
It is thus important to request this limit on the VM file descriptor
rather than on the one that corresponds to /dev/kvm, as the latter
is likely to return something that doesn't take the constraints into
account.
Reported-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
kvm.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kvm.c b/kvm.c
index e327541..3d5173d 100644
--- a/kvm.c
+++ b/kvm.c
@@ -406,7 +406,7 @@ int kvm__recommended_cpus(struct kvm *kvm)
{
int ret;
- ret = ioctl(kvm->sys_fd, KVM_CHECK_EXTENSION, KVM_CAP_NR_VCPUS);
+ ret = ioctl(kvm->vm_fd, KVM_CHECK_EXTENSION, KVM_CAP_NR_VCPUS);
if (ret <= 0)
/*
* api.txt states that if KVM_CAP_NR_VCPUS does not exist,
@@ -421,7 +421,7 @@ int kvm__max_cpus(struct kvm *kvm)
{
int ret;
- ret = ioctl(kvm->sys_fd, KVM_CHECK_EXTENSION, KVM_CAP_MAX_VCPUS);
+ ret = ioctl(kvm->vm_fd, KVM_CHECK_EXTENSION, KVM_CAP_MAX_VCPUS);
if (ret <= 0)
ret = kvm__recommended_cpus(kvm);
--
2.26.2
