From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-69.mta0.migadu.com [91.218.175.69]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 31300518142 for ; Thu, 1 Oct 2026 13:57:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.69 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790863063; cv=none; b=OV6wW/Rt/9lCeoHcGyMEWOo6Z9v4ow5xrBGKAfopE40KGn8yA+pNCpW4QsH0xBwyMlb4o5j3qxA5XuDfyMIKNq2IBGtMGFA86j3BcplO/KNZa/BzE80Q9fm+mnaoJwk88ztSkPApGAewF+Jnv4uqpGwz48QaUFIfUCnngOulWD0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790863063; c=relaxed/simple; bh=1Ws9n6iE1+OrWs/XcdHuXlvIueQS+tIjV4+vXzqVwmw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=GmJCm/352hZQGUU5ECgYZGlVUKt/JnvQnoVKExM6iA/syk7+0Gt72BGTNK+8nkxHHP7g9uaiJWPphhbNK5xGqYrpvgc+TougFzgzuE3Pqe/G7LGQqvLMIxdwvfP6+vsmgaflORBlXjayUewEa7xkqtot9wv9jgiNuVERKrGKsTE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=vXZh9OT2; arc=none smtp.client-ip=91.218.175.69 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="vXZh9OT2" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=1Ws9n6iE1+OrWs/XcdHuXlvIueQS+tIjV4+vXzqVwmw=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790863055; v=1; x=1791467855; b=vXZh9OT2GH+8/cDS93zQVOupF1QRfQWYYgYhatoqfaOJ7tb9uzEPJqYf0u4YZCBQKl95axC+ x6GhSDoYIFVyicuwED89RnB1HqeIpSuVDD1bt0/j6SYBtUJ9s6d/XUqFv8j59bH9TxYi0LHag+o Y5ti5vlC1UxoW0JjZnRsnIzI= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id e098126e4f2d483f; Thu, 01 Oct 2026 13:57:35 +0000 X-Mizu-Trace-ID: e098126e4f2d483f X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: maz@kernel.org, oupton@kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: catalin.marinas@arm.com, will@kernel.org, joey.gouly@arm.com, seiden@linux.ibm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, mark.rutland@arm.com, steven.price@arm.com, vdonnefort@google.com, qperret@google.com, tabba@google.com Subject: [PATCH v4 04/18] KVM: arm64: Disable steal time for protected VMs Date: Thu, 1 Oct 2026 14:56:57 +0100 Message-Id: <20261001135711.1640520-5-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20261001135711.1640520-1-fuad.tabba@linux.dev> References: <20261001135711.1640520-1-fuad.tabba@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit pKVM doesn't support steal time for protected guests, and KVM_CAP_STEAL_TIME already reads 0 for them on the VM file descriptor, but kvm_arm_pvtime_supported() takes no VM, so the host still accepts the KVM_ARM_VCPU_PVTIME_CTRL attribute, whose IPA would point kvm_update_stolen_time() at the guest's private memory on every vCPU load. Pass the VM in and return false for a protected one, so the attribute returns -ENXIO as it does where steal time isn't implemented. Reviewed-by: Vincent Donnefort Signed-off-by: Fuad Tabba --- 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 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..053fe831fa541 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, @@ -81,7 +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; -- 2.39.5