diff mbox series

[RFC,22/28] arm64: Don't expose stolen time for realm guests

Message ID 20230127112932.38045-23-steven.price@arm.com (mailing list archive)
State New, archived
Headers show
Series arm64: Support for Arm CCA in KVM | expand

Commit Message

Steven Price Jan. 27, 2023, 11:29 a.m. UTC 
It doesn't make much sense and with the ABI as it is it's a footgun for
the VMM which makes fatal granule protection faults easy to trigger.

Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/arm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 46c152a9a150..645df5968e1e 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -302,7 +302,10 @@  int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		r = system_supports_mte();
 		break;
 	case KVM_CAP_STEAL_TIME:
-		r = kvm_arm_pvtime_supported();
+		if (kvm && kvm_is_realm(kvm))
+			r = 0;
+		else
+			r = kvm_arm_pvtime_supported();
 		break;
 	case KVM_CAP_ARM_EL1_32BIT:
 		r = cpus_have_const_cap(ARM64_HAS_32BIT_EL1);