From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2642ACA5FCB for ; Thu, 1 Oct 2026 13:58:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=BCTBRBnQKS1H3xHTNYsoSU9MklcmQZ0VHVNoZcdPf98=; b=iHeSbFKc4ULMBIhiCK58NBtApy kzzhx6DkAsgTto+roS3t2NPrETry9aJhRSKWr1TrcqdHs2hU+Y3gJCpu9DnbLnJCanbRdUysmMVEr UDtI2CQ9EQEwi/VMrotgU2rXcpL12KE4TjQ2ASb9r79sQwz7yVR3s0i0x2VZkDQIA3LjbOpCpkVqS PyKalTOVyBtwmhbUyFHQ34sqthDX+6+BFmhj49T14HbpQl+m1V3p2E17uv9DlGS2HpVCfh9f2uvAO kwwYUBAZUy6mbH5wgal4Wi/FrZGpC7HEHA6gWQHMtx1qQLtns7lbQ3lucX4km7GVAeLeuCHbueSWu TLahuwxg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xCHJ9-00000009J6T-32Xs; Thu, 01 Oct 2026 13:58:47 +0000 Received: from out-50.mta1.migadu.com ([95.215.58.50] helo=mta1.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xCHJ7-00000009J3o-3uRy for linux-arm-kernel@lists.infradead.org; Thu, 01 Oct 2026 13:58:47 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=XWE8MuJsJ9e7UfacDyXUgTl5aLh076wgSHsAAG8fiBg=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790863124; v=1; x=1791467924; b=wO0132znEVl5PGgdLJy3DxeQ2O499Gl6s0UmmcpDneo+O89+r0XHteavdzOR3o9DpxZFJfHP watxgdiT0MJPu93WtW2CDJMUnw4ggGhEKkceZI6ZKTimows8Fla+4N4vMRIVaUpVXDOPgriUL46 iVJ0FKERa86+730zKOin9gPU= X-Envelope-To: linux-arm-kernel@lists.infradead.org Received: by smtp.migadu.com with ESMTPS id 87ed9d2d75c0e355; Thu, 01 Oct 2026 13:58:44 +0000 X-Mizu-Trace-ID: 87ed9d2d75c0e355 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 11/18] KVM: arm64: Restrict KVM_ARM_VCPU_INIT and PSCI version for protected VMs Date: Thu, 1 Oct 2026 14:57:04 +0100 Message-Id: <20261001135711.1640520-12-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> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261001_065846_125025_47A10FF9 X-CRM114-Status: GOOD ( 14.70 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org EL2 masks a protected VM's vCPU features down to the set pKVM allows, so a KVM_ARM_VCPU_INIT that requests more succeeds and produces a guest without them. Reject such an init with -EINVAL. The host and EL2 both take the allowed set from kvm_pkvm_vcpu_allowed_features(). EL2 returns 1.1 for a protected guest's PSCI_VERSION whatever the host is configured for, and forwards the platform calls to the host. Require KVM_ARM_VCPU_PSCI_0_2: without it the host dispatches the forwarded calls as PSCI 0.1. Reject a KVM_REG_ARM_PSCI_VERSION write below 1.1: below it the host rejects the SYSTEM_RESET2 that EL2 advertises. Signed-off-by: Fuad Tabba --- arch/arm64/include/asm/kvm_pkvm.h | 24 ++++++++++++++++++++++++ arch/arm64/kvm/arm.c | 13 +++++++++++++ arch/arm64/kvm/hyp/nvhe/pkvm.c | 17 ++--------------- arch/arm64/kvm/hypercalls.c | 7 +++++++ 4 files changed, 46 insertions(+), 15 deletions(-) diff --git a/arch/arm64/include/asm/kvm_pkvm.h b/arch/arm64/include/asm/kvm_pkvm.h index beea00e693a0a..fbea052fa3e16 100644 --- a/arch/arm64/include/asm/kvm_pkvm.h +++ b/arch/arm64/include/asm/kvm_pkvm.h @@ -53,6 +53,30 @@ static inline bool kvm_pkvm_ext_allowed(struct kvm *kvm, long ext) } } +/* + * The vCPU features a protected VM may use: checked by the host at + * KVM_ARM_VCPU_INIT, applied by EL2 when the hyp VM is created. + */ +static inline void kvm_pkvm_vcpu_allowed_features(struct kvm *kvm, + unsigned long *allowed) +{ + bitmap_zero(allowed, KVM_VCPU_MAX_FEATURES); + + set_bit(KVM_ARM_VCPU_PSCI_0_2, allowed); + + if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_PMU_V3)) + set_bit(KVM_ARM_VCPU_PMU_V3, allowed); + + if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_PTRAUTH_ADDRESS)) + set_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, allowed); + + if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_PTRAUTH_GENERIC)) + set_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, allowed); + + if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_SVE)) + set_bit(KVM_ARM_VCPU_SVE, allowed); +} + /* * Check whether the KVM VM IOCTL is allowed in pKVM. * diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index cceeeee266902..ca6e109b3e5d6 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1620,6 +1620,19 @@ static int kvm_vcpu_init_check_features(struct kvm_vcpu *vcpu, if (features & ~system_supported_vcpu_features()) return -EINVAL; + /* Reject features EL2 would drop when it creates the hyp VM. */ + if (vcpu_is_protected(vcpu)) { + DECLARE_BITMAP(allowed, KVM_VCPU_MAX_FEATURES); + + kvm_pkvm_vcpu_allowed_features(vcpu->kvm, allowed); + if (!bitmap_subset(&features, allowed, KVM_VCPU_MAX_FEATURES)) + return -EINVAL; + + /* EL2 implements PSCI 1.1; the host must not dispatch as 0.1. */ + if (!test_bit(KVM_ARM_VCPU_PSCI_0_2, &features)) + return -EINVAL; + } + /* * For now make sure that both address/generic pointer authentication * features are requested by the userspace together. diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c index dcc1db6201f14..696f999996b13 100644 --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c @@ -410,23 +410,10 @@ static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struc if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_MTE)) kvm->arch.flags |= host_arch_flags & BIT(KVM_ARCH_FLAG_MTE_ENABLED); - bitmap_zero(allowed_features, KVM_VCPU_MAX_FEATURES); + kvm_pkvm_vcpu_allowed_features(kvm, allowed_features); - set_bit(KVM_ARM_VCPU_PSCI_0_2, allowed_features); - - if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_PMU_V3)) - set_bit(KVM_ARM_VCPU_PMU_V3, allowed_features); - - if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_PTRAUTH_ADDRESS)) - set_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, allowed_features); - - if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_PTRAUTH_GENERIC)) - set_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, allowed_features); - - if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_SVE)) { - set_bit(KVM_ARM_VCPU_SVE, allowed_features); + if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_SVE)) kvm->arch.flags |= host_arch_flags & BIT(KVM_ARCH_FLAG_GUEST_HAS_SVE); - } bitmap_and(kvm->arch.vcpu_features, host_kvm->arch.vcpu_features, allowed_features, KVM_VCPU_MAX_FEATURES); diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c index b11b8821c9fbc..e43ed13c82bec 100644 --- a/arch/arm64/kvm/hypercalls.c +++ b/arch/arm64/kvm/hypercalls.c @@ -580,6 +580,13 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) wants_02 = vcpu_has_feature(vcpu, KVM_ARM_VCPU_PSCI_0_2); + /* + * EL2 advertises PSCI 1.1; the host handles the forwarded calls + * by this version. + */ + if (vcpu_is_protected(vcpu) && val < KVM_ARM_PSCI_1_1) + return -EINVAL; + switch (val) { case KVM_ARM_PSCI_0_1: if (wants_02) -- 2.39.5