[PATCH kvmtool 4/5] arm64: Query steal-time support on the VM fd

[Fuad Tabba <fuad.tabba@linux.dev>]

kvm_cpu__setup_pvtime() probes KVM_CAP_STEAL_TIME with
kvm__supports_extension(), which issues KVM_CHECK_EXTENSION on the
global /dev/kvm fd. That reports the host's raw capabilities, unaware of
any per-VM restrictions.

pKVM does not offer steal-time to a protected VM, and reflects that on
the VM fd alone. kvmtool goes on to KVM_HAS_DEVICE_ATTR, the kernel
refuses the PVTIME attribute with -EPERM, and kvm_cpu__arch_init() dies:

  Fatal: Unable to initialise vcpu

Query it on the VM fd via kvm__supports_vm_extension(), as
commit 84464ba0246b ("arm64: Query per-VM capabilities when selecting
vCPU features") did for the vCPU feature probes. kvmtool then takes the
no_pvtime path it already has when steal-time is unsupported.

Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
---
 arm64/pvtime.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arm64/pvtime.c b/arm64/pvtime.c
index 2933ac7..839aa8a 100644
--- a/arm64/pvtime.c
+++ b/arm64/pvtime.c
@@ -58,8 +58,8 @@ int kvm_cpu__setup_pvtime(struct kvm_cpu *vcpu)
 	if (kvm_cfg->no_pvtime)
 		return 0;
 
-	has_stolen_time = kvm__supports_extension(vcpu->kvm,
-						  KVM_CAP_STEAL_TIME);
+	has_stolen_time = kvm__supports_vm_extension(vcpu->kvm,
+						     KVM_CAP_STEAL_TIME);
 	if (!has_stolen_time) {
 		kvm_cfg->no_pvtime = true;
 		return 0;
-- 
2.39.5