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authorAndrew Jones <drjones@redhat.com>2020-08-04 19:06:04 +0200
committerMarc Zyngier <maz@kernel.org>2020-08-21 14:05:19 +0100
commit004a01241c5a0d375266ebf1c72f208de99294e9 (patch)
tree956e8aee5d5a69cbbdf3d5dff427bae747a003b1 /arch/arm64/kvm
parent739c7af7daeede8e2ec78392f2617c965ce0342a (diff)
downloadlinux-004a01241c5a0d375266ebf1c72f208de99294e9.tar.bz2
arm64/x86: KVM: Introduce steal-time cap
arm64 requires a vcpu fd (KVM_HAS_DEVICE_ATTR vcpu ioctl) to probe support for steal-time. However this is unnecessary, as only a KVM fd is required, and it complicates userspace (userspace may prefer delaying vcpu creation until after feature probing). Introduce a cap that can be checked instead. While x86 can already probe steal-time support with a kvm fd (KVM_GET_SUPPORTED_CPUID), we add the cap there too for consistency. Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Steven Price <steven.price@arm.com> Link: https://lore.kernel.org/r/20200804170604.42662-7-drjones@redhat.com
Diffstat (limited to 'arch/arm64/kvm')
-rw-r--r--arch/arm64/kvm/arm.c3
-rw-r--r--arch/arm64/kvm/pvtime.c2
2 files changed, 4 insertions, 1 deletions
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 691d21e4c717..57876b0b870b 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -206,6 +206,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
*/
r = 1;
break;
+ case KVM_CAP_STEAL_TIME:
+ r = kvm_arm_pvtime_supported();
+ break;
default:
r = kvm_arch_vm_ioctl_check_extension(kvm, ext);
break;
diff --git a/arch/arm64/kvm/pvtime.c b/arch/arm64/kvm/pvtime.c
index 75234321d896..920ac43077ad 100644
--- a/arch/arm64/kvm/pvtime.c
+++ b/arch/arm64/kvm/pvtime.c
@@ -71,7 +71,7 @@ gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu)
return base;
}
-static bool kvm_arm_pvtime_supported(void)
+bool kvm_arm_pvtime_supported(void)
{
return !!sched_info_on();
}