[PATCH v17 10/20] KVM: arm64: coco: Disable Steal time accounting for coco guests

[Suzuki K Poulose <suzuki.poulose@arm.com>]

PVTIME support is advertised by KVM_CAP_STEAL_TIME, which doesn't take into
account the kvm instance. Even with that, a VMM could skip the CAP check and
proceed to configure the PVTIME as we don't do further check on the DEVICE_CTRL.
Tighten this up by passing the KVM instance around wherever possible and
catch things early

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 arch/arm64/include/asm/kvm_host.h |  2 +-
 arch/arm64/kvm/arm.c              |  2 +-
 arch/arm64/kvm/pvtime.c           | 10 +++++-----
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 020aef5a1b698..0f258f16fdf81 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1367,7 +1367,7 @@ long kvm_hypercall_pv_features(struct kvm_vcpu *vcpu);
 gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu);
 void kvm_update_stolen_time(struct kvm_vcpu *vcpu);
 
-bool kvm_arm_pvtime_supported(void);
+bool kvm_arm_pvtime_supported(struct kvm *kvm);
 int kvm_arm_pvtime_set_attr(struct kvm_vcpu *vcpu,
 			    struct kvm_device_attr *attr);
 int kvm_arm_pvtime_get_attr(struct kvm_vcpu *vcpu,
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 2ecd92156f7cc..b5e0893ea16f1 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -473,7 +473,7 @@ 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();
+		r = kvm_arm_pvtime_supported(kvm);
 		break;
 	case KVM_CAP_ARM_EL1_32BIT:
 		r = cpus_have_final_cap(ARM64_HAS_32BIT_EL1);
diff --git a/arch/arm64/kvm/pvtime.c b/arch/arm64/kvm/pvtime.c
index 4ceabaa4c30bd..41fbfd92cd292 100644
--- a/arch/arm64/kvm/pvtime.c
+++ b/arch/arm64/kvm/pvtime.c
@@ -67,9 +67,9 @@ gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu)
 	return base;
 }
 
-bool kvm_arm_pvtime_supported(void)
+bool kvm_arm_pvtime_supported(struct kvm *kvm)
 {
-	return !!sched_info_on();
+	return !!sched_info_on() && (!kvm || !kvm_vm_is_confidential(kvm));
 }
 
 int kvm_arm_pvtime_set_attr(struct kvm_vcpu *vcpu,
@@ -81,7 +81,7 @@ int kvm_arm_pvtime_set_attr(struct kvm_vcpu *vcpu,
 	int ret = 0;
 	int idx;
 
-	if (!kvm_arm_pvtime_supported() ||
+	if (!kvm_arm_pvtime_supported(kvm) ||
 	    attr->attr != KVM_ARM_VCPU_PVTIME_IPA)
 		return -ENXIO;
 
@@ -110,7 +110,7 @@ int kvm_arm_pvtime_get_attr(struct kvm_vcpu *vcpu,
 	u64 __user *user = (u64 __user *)attr->addr;
 	u64 ipa;
 
-	if (!kvm_arm_pvtime_supported() ||
+	if (!kvm_arm_pvtime_supported(vcpu->kvm) ||
 	    attr->attr != KVM_ARM_VCPU_PVTIME_IPA)
 		return -ENXIO;
 
@@ -126,7 +126,7 @@ int kvm_arm_pvtime_has_attr(struct kvm_vcpu *vcpu,
 {
 	switch (attr->attr) {
 	case KVM_ARM_VCPU_PVTIME_IPA:
-		if (kvm_arm_pvtime_supported())
+		if (kvm_arm_pvtime_supported(vcpu->kvm))
 			return 0;
 	}
 	return -ENXIO;
-- 
2.43.0