From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: kvm@vger.kernel.org, kvmarm@lists.linux.dev
Cc: maz@kernel.org, will@kernel.org, catalin.marinas@arm.com,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, steven.price@arm.com,
aneesh.kumar@kernel.org, oupton@kernel.org, gshan@redhat.com,
joey.gouly@arm.com, tabba@google.com, yuzenghui@huawei.com,
linux-coco@lists.linux.dev, gankulkarni@os.amperecomputing.com,
sdonthineni@nvidia.com, alpergun@google.com,
fj0570is@fujitsu.com, WeiLin.Chang@arm.com,
lpieralisi@kernel.org, enju.kohei@fujitsu.com,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Fuad Tabba <fuad.tabba@linux.dev>
Subject: [PATCH v19 02/20] KVM: arm64: Disable Steal time accounting for protected guests
Date: Sun, 20 Sep 2026 22:28:27 +0100 [thread overview]
Message-ID: <20260920212845.707-3-suzuki.poulose@arm.com> (raw)
In-Reply-To: <20260920212845.707-1-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.
Reviewed-by: Fuad Tabba <fuad.tabba@linux.dev>
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 | 14 +++++++-------
3 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 27fe0cd5b2d7a..286489a69dff5 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1346,7 +1346,7 @@ 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 8b080804bc90b..db36815630790 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -447,7 +447,7 @@ 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..579e0a4720ad2 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_protected(kvm));
}
int kvm_arm_pvtime_set_attr(struct kvm_vcpu *vcpu,
@@ -81,8 +81,8 @@ int kvm_arm_pvtime_set_attr(struct kvm_vcpu *vcpu,
int ret = 0;
int idx;
- if (!kvm_arm_pvtime_supported() ||
- attr->attr != KVM_ARM_VCPU_PVTIME_IPA)
+ if (!kvm_arm_pvtime_supported(kvm) ||
+ (attr->attr != KVM_ARM_VCPU_PVTIME_IPA))
return -ENXIO;
if (get_user(ipa, user))
@@ -110,8 +110,8 @@ int kvm_arm_pvtime_get_attr(struct kvm_vcpu *vcpu,
u64 __user *user = (u64 __user *)attr->addr;
u64 ipa;
- if (!kvm_arm_pvtime_supported() ||
- attr->attr != KVM_ARM_VCPU_PVTIME_IPA)
+ if (!kvm_arm_pvtime_supported(vcpu->kvm) ||
+ (attr->attr != KVM_ARM_VCPU_PVTIME_IPA))
return -ENXIO;
ipa = vcpu->arch.steal.base;
@@ -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
next prev parent reply other threads:[~2026-09-20 21:29 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-20 21:28 [PATCH v19 00/20] KVM: arm64: CCA: Add basic plumbing for Realms Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 01/20] KVM: arm64: protected VM: Handle user writes to CNTVCT_EL0/CNTPCT_EL0 Suzuki K Poulose
2026-09-20 21:28 ` Suzuki K Poulose [this message]
2026-09-20 21:28 ` [PATCH v19 03/20] KVM: arm64: Include kvm_emulate.h in kvm/arm_psci.h Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 04/20] KVM: arm64: Avoid including linux/kvm_host.h in kvm_pgtable.h Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 05/20] KVM: arm64: Track the type of VM in kvm_arch Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 06/20] KVM: arm64: Refactor the vcpu_load to allow for VM specific callbacks Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 07/20] KVM: arm64: Add vcpu load/put call backs for flavors Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 08/20] KVM: arm64: Reuse kvm_stage2_unmap_range in kvm_unmap_gfn_range Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 09/20] KVM: arm64: Add VM specific callback for S2 MMU operations Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 10/20] KVM: arm64: Abstract out memory abort handling Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 11/20] KVM: arm64: Mandate VGIC v3 for for VMs running on hyp that don't trust the host Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 12/20] KVM: arm64: CCA: Add a new mode for supporting Realm guests Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 13/20] KVM: arm64: CCA: Add VCPU load/put for Realms Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 14/20] KVM: arm64: CCA: Add bare minimal S2 operations for Realm Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 15/20] KVM: arm64: CCA: Introduce Realms Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 16/20] KVM: arm64: CCA: Don't expose unsupported capabilities for realm guests Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 17/20] KVM: arm64: CCA: WARN on injected undef exceptions Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 18/20] KVM: arm64: CCA: Support timers in realm RECs Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 19/20] KVM: arm64: CCA: Expose SVE VL register before VCPU finalization Suzuki K Poulose
2026-09-20 21:28 ` [PATCH v19 20/20] KVM: arm64: CCA: Control user register access for Realms Suzuki K Poulose
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