From nobody Sat Oct 24 20:15:28 2026 Received: from mta0.migadu.com (out-75.mta0.migadu.com [91.218.175.75]) (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 076E53C76AD for ; Sun, 11 Oct 2026 14:36:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.75 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791729415; cv=none; b=TS17yAfnM5yS6GFDuljCXSjxddsgwLrLRK/OZjsSQWoIjjUYlNju9nswLvWfU2MVv8XTvxBiLYt971jqIWwgzOwqDIm52GP+dcpa1MPTCgMIRnA8w6suQYbo8y9EYuPM3cbzSnn7aK5PaDzJ8+tKohfNXAQ9EgqojjJh9vt58m0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791729415; c=relaxed/simple; bh=OYn21/OL8lrH8NaEq6iDghNkvvHb7mfdPr+Xymc5Uv4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=B0gXjKqqjdwG3OkDLGOzp+aGp3y2aY5Qg1iwWfgznhDRlAY7S46G5PHegk2MViSOXqh6HOPoJAV41BV3olQGRHvt/tLY9rcupyH9atEm1q9fQEbAw5ECVY65lGnnFzRNMzhNGVjPyXFiCTIox7q/N4MjO4a835GP1mH9u6lSnRs= 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=pagB3q/F; arc=none smtp.client-ip=91.218.175.75 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="pagB3q/F" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=OYn21/OL8lrH8NaEq6iDghNkvvHb7mfdPr+Xymc5Uv4=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1791729410; v=1; x=1792334210; b=pagB3q/FkgcGgbi/SX8/Y4X6grPtD6gyyVgB3lIw4yE2QjFrRLWAgs8Fpw0XZ3iyJjHH+ChN RawBGI6CSXQFaCT8w0MD6NzJr+7rPFZeKbFdHt8H92kD4P9hgPu/d3ypsU6RiKwOgcsONCRnVCH F45f1cl0XPiD9ISsHct75XaY= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id c296a38619e6afa6; Sun, 11 Oct 2026 14:36:50 +0000 X-Mizu-Trace-ID: c296a38619e6afa6 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, vdonnefort@google.com, qperret@google.com, Sascha.Bischoff@arm.com, steven.price@arm.com, tabba@google.com Subject: [PATCH v2 1/5] KVM: arm64: Reject the GICv5 CPU interface hypercalls under pKVM Date: Sun, 11 Oct 2026 15:36:44 +0100 Message-Id: <20261011143648.211337-2-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20261011143648.211337-1-fuad.tabba@linux.dev> References: <20261011143648.211337-1-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: quoted-printable Content-Type: text/plain; charset="utf-8" __vgic_v5_save_apr() and __vgic_v5_restore_vmcr_apr() remain callable once pKVM has finalised. pKVM never registers a GICv5 vgic, so neither has a valid caller in protected mode, and on a GICv3 machine both reach a register that is UNDEFINED at EL2 and panic the hypervisor. Move both into the band the dispatcher rejects once pKVM has finalised. Fixes: af325e87af5da ("KVM: arm64: gic-v5: Add vgic-v5 save/restore hyp int= erface") Signed-off-by: Fuad Tabba Reviewed-by: Suzuki K Poulose --- arch/arm64/include/asm/kvm_asm.h | 4 ++-- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_= asm.h index e5b92ac09e69e..ea319c496bb26 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -62,6 +62,8 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___kvm_enable_ssbs, __KVM_HOST_SMCCC_FUNC___vgic_v3_init_lrs, __KVM_HOST_SMCCC_FUNC___vgic_v3_get_gic_config, + __KVM_HOST_SMCCC_FUNC___vgic_v5_save_apr, + __KVM_HOST_SMCCC_FUNC___vgic_v5_restore_vmcr_apr, =20 MARKER(__KVM_HOST_SMCCC_FUNC_MIN_PKVM), =20 @@ -87,8 +89,6 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___tracing_write_event, __KVM_HOST_SMCCC_FUNC___vgic_v3_save_aprs, __KVM_HOST_SMCCC_FUNC___vgic_v3_restore_vmcr_aprs, - __KVM_HOST_SMCCC_FUNC___vgic_v5_save_apr, - __KVM_HOST_SMCCC_FUNC___vgic_v5_restore_vmcr_apr, =20 MARKER(__KVM_HOST_SMCCC_FUNC_PKVM_ONLY), =20 diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/h= yp-main.c index 9a3b92e626adb..7c939baf9c1ba 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -911,6 +911,8 @@ static const hcall_t host_hcall[] =3D { HANDLE_FUNC(__kvm_enable_ssbs), HANDLE_FUNC(__vgic_v3_init_lrs), HANDLE_FUNC(__vgic_v3_get_gic_config), + HANDLE_FUNC(__vgic_v5_save_apr), + HANDLE_FUNC(__vgic_v5_restore_vmcr_apr), HANDLE_FUNC(__pkvm_prot_finalize), =20 HANDLE_FUNC(__kvm_adjust_pc), @@ -932,8 +934,6 @@ static const hcall_t host_hcall[] =3D { HANDLE_FUNC(__tracing_write_event), HANDLE_FUNC(__vgic_v3_save_aprs), HANDLE_FUNC(__vgic_v3_restore_vmcr_aprs), - HANDLE_FUNC(__vgic_v5_save_apr), - HANDLE_FUNC(__vgic_v5_restore_vmcr_apr), =20 HANDLE_FUNC(__pkvm_host_share_hyp), HANDLE_FUNC(__pkvm_host_unshare_hyp), --=20 2.39.5 From nobody Sat Oct 24 20:15:28 2026 Received: from mta1.migadu.com (out-142.mta1.migadu.com [95.215.58.142]) (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 79820457E45 for ; 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arc=none smtp.client-ip=95.215.58.142 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="CD6XUNik" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=UabJMBs9Z2dMomcvezICknlRvRSdmtK2yTGhqNrS3jk=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1791729413; v=1; x=1792334213; b=CD6XUNikE/0hSOs+fSeODgrWZ6EdBpDl5CDYDU6jlK6BBPFsnhJJPL4rdvTA6VVq5UhuVUw6 7NP8SiyPb4ZoFk/z/8Rzf2CuRS6SU/aWaSEWoU/PGd+JY5Rnad1wipdjap70V9Lu4lKL/ZzcLXo 71dWlLqIsXVWkfnmkEwr/O5w= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 9b626a34dbb21967; Sun, 11 Oct 2026 14:36:53 +0000 X-Mizu-Trace-ID: 9b626a34dbb21967 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, vdonnefort@google.com, qperret@google.com, Sascha.Bischoff@arm.com, steven.price@arm.com, tabba@google.com Subject: [PATCH v2 2/5] KVM: arm64: Reject the stage-2 flush hypercalls under pKVM Date: Sun, 11 Oct 2026 15:36:45 +0100 Message-Id: <20261011143648.211337-3-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20261011143648.211337-1-fuad.tabba@linux.dev> References: <20261011143648.211337-1-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: quoted-printable Content-Type: text/plain; charset="utf-8" The stage-2 TLB and context flush hypercalls remain callable once pKVM has finalised, and five of the six dereference a host-supplied struct kvm_s2_mmu pointer. Under pKVM none has a valid caller: the host walks no guest stage-2, its TLB flushes go through the handle-based __pkvm_tlb_flush_vmid, and kvm_arch_vcpu_load() skips both the VMID update and the CPU context flush. Move them into the band the dispatcher rejects once pKVM has finalised. Reported-by: Sashiko Closes: https://lore.kernel.org/all/20260914130152.F0D5F1F000FF@smtp.kernel= .org/ Signed-off-by: Fuad Tabba Reviewed-by: Suzuki K Poulose --- arch/arm64/include/asm/kvm_asm.h | 12 ++++++------ arch/arm64/kvm/hyp/nvhe/hyp-main.c | 11 ++++++----- 2 files changed, 12 insertions(+), 11 deletions(-) diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_= asm.h index ea319c496bb26..b182c908c1a98 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -64,6 +64,12 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___vgic_v3_get_gic_config, __KVM_HOST_SMCCC_FUNC___vgic_v5_save_apr, __KVM_HOST_SMCCC_FUNC___vgic_v5_restore_vmcr_apr, + __KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context, + __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_ipa, + __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_ipa_nsh, + __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid, + __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_range, + __KVM_HOST_SMCCC_FUNC___kvm_flush_cpu_context, =20 MARKER(__KVM_HOST_SMCCC_FUNC_MIN_PKVM), =20 @@ -72,12 +78,6 @@ enum __kvm_host_smccc_func { /* Hypercalls that are always available and common to [nh]VHE/pKVM. */ __KVM_HOST_SMCCC_FUNC___kvm_adjust_pc, __KVM_HOST_SMCCC_FUNC___kvm_vcpu_run, - __KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context, - __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_ipa, - __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_ipa_nsh, - __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid, - __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_range, - __KVM_HOST_SMCCC_FUNC___kvm_flush_cpu_context, __KVM_HOST_SMCCC_FUNC___kvm_timer_set_cntvoff, __KVM_HOST_SMCCC_FUNC___tracing_load, __KVM_HOST_SMCCC_FUNC___tracing_unload, diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/h= yp-main.c index 7c939baf9c1ba..b2657a3c65b40 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -913,16 +913,16 @@ static const hcall_t host_hcall[] =3D { HANDLE_FUNC(__vgic_v3_get_gic_config), HANDLE_FUNC(__vgic_v5_save_apr), HANDLE_FUNC(__vgic_v5_restore_vmcr_apr), - HANDLE_FUNC(__pkvm_prot_finalize), - - HANDLE_FUNC(__kvm_adjust_pc), - HANDLE_FUNC(__kvm_vcpu_run), HANDLE_FUNC(__kvm_flush_vm_context), HANDLE_FUNC(__kvm_tlb_flush_vmid_ipa), HANDLE_FUNC(__kvm_tlb_flush_vmid_ipa_nsh), HANDLE_FUNC(__kvm_tlb_flush_vmid), HANDLE_FUNC(__kvm_tlb_flush_vmid_range), HANDLE_FUNC(__kvm_flush_cpu_context), + HANDLE_FUNC(__pkvm_prot_finalize), + + HANDLE_FUNC(__kvm_adjust_pc), + HANDLE_FUNC(__kvm_vcpu_run), HANDLE_FUNC(__kvm_timer_set_cntvoff), HANDLE_FUNC(__tracing_load), HANDLE_FUNC(__tracing_unload), @@ -969,7 +969,8 @@ static void handle_host_hcall(struct kvm_cpu_context *h= ost_ctxt) =20 /* * If pKVM has been initialised then reject any calls to the - * early "privileged" hypercalls. Note that we cannot reject + * early "privileged" hypercalls, and to the ones the host has no + * use for in protected mode. Note that we cannot reject * calls to __pkvm_prot_finalize for two reasons: (1) The static * key used to determine initialisation must be toggled prior to * finalisation and (2) finalisation is performed on a per-CPU --=20 2.39.5 From nobody Sat Oct 24 20:15:28 2026 Received: from mta1.migadu.com (out-145.mta1.migadu.com [95.215.58.145]) (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 1FD494582F6 for ; Sun, 11 Oct 2026 14:36:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.145 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791729421; cv=none; b=KHio5IL/gPvjkxcHddFIl26o5TBh9x4RTzAKR64R9HjjGUdZA0U+bhxow8ZjnFdWMCl55N/jBNZ+kwVM4q42ye3+WV3gulArQBS937IdadnAqoAXABCRUPoitCq4sTPe++Jg46DAzYrjfWrhcYva3qBtYHYDlsLpJBInfeITwvs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791729421; c=relaxed/simple; bh=kI4k7LKRskEk7+Aou1508QIGGibzNJmNHk2adKMVvWo=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=tXv9DrMQJlbvctq5Tfd9simjIGoblLoDRqkWH4gaG3O0xRCrTDegnO+3fWLkX80m0XngxTIY5nRm3BX9p2NEljRNVDGjKCM6FqUrCC8tH4hx86tVtb4Jxr6THj+IBk0XWp0yNESfVd6+N/6jCvzNWcESXkCGKPI8gHJesvazdTM= 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=ov8XNhVR; arc=none smtp.client-ip=95.215.58.145 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="ov8XNhVR" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=kI4k7LKRskEk7+Aou1508QIGGibzNJmNHk2adKMVvWo=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1791729414; v=1; x=1792334214; b=ov8XNhVRxvhpv5wQO/L/CJrPBS2+qvEuH99qe37jDJWRiQxOrtIiTvtwZWcl56ga0ztYJDuu QZiAzHfyzxGdCf/BKuVCTrT18caYD/GFX6dpNzKBTWtaWla8Nv6GGEeYIIgC5rECEbycpP1y7zT gPTTMMq6HUOitJhTW6NAQt5Y= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 4bc7a2959fe86583; Sun, 11 Oct 2026 14:36:54 +0000 X-Mizu-Trace-ID: 4bc7a2959fe86583 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, vdonnefort@google.com, qperret@google.com, Sascha.Bischoff@arm.com, steven.price@arm.com, tabba@google.com Subject: [PATCH v2 3/5] KVM: arm64: Validate the host-provided vgic model in pKVM Date: Sun, 11 Oct 2026 15:36:46 +0100 Message-Id: <20261011143648.211337-4-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20261011143648.211337-1-fuad.tabba@linux.dev> References: <20261011143648.211337-1-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: quoted-printable Content-Type: text/plain; charset="utf-8" EL2 copies vgic_model from the host's struct kvm unchecked, and the nVHE world switch dispatches on it with no cpucap guard. A host writing KVM_DEV_TYPE_ARM_VGIC_V5 makes EL2 access GICv5 CPU interface registers that are UNDEFINED without FEAT_GCIE, and panics the hypervisor on any GICv3 machine. Accept only GICv3, the one model pKVM supports, and force anything else to 0, as for a VM with no in-kernel irqchip. EL2 reads the model only to pick the GICv5 world switch and to emulate GICv3 CPU interface accesses, and the host's own copy is left alone. Fixes: 9b8e3d4ca0e73 ("KVM: arm64: gic-v5: Implement GICv5 load/put and sav= e/restore") Signed-off-by: Fuad Tabba Reviewed-by: Suzuki K Poulose --- arch/arm64/kvm/hyp/nvhe/pkvm.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c index 459bd9eb7e4bc..a9d0e94709199 100644 --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c @@ -340,13 +340,19 @@ static void pkvm_init_features_from_host(struct pkvm_= hyp_vm *hyp_vm, const struc { struct kvm *kvm =3D &hyp_vm->kvm; unsigned long host_arch_flags =3D READ_ONCE(host_kvm->arch.flags); + u32 vgic_model =3D READ_ONCE(host_kvm->arch.vgic.vgic_model); DECLARE_BITMAP(allowed_features, KVM_VCPU_MAX_FEATURES); =20 /* CTR_EL0 is always under host control, even for protected VMs. */ hyp_vm->kvm.arch.ctr_el0 =3D host_kvm->arch.ctr_el0; =20 - /* Preserve the vgic model so that GICv3 emulation works */ - hyp_vm->kvm.arch.vgic.vgic_model =3D host_kvm->arch.vgic.vgic_model; + /* + * pKVM runs only GICv3. Anything else becomes 0, the model of a VM + * with no in-kernel irqchip, which keeps EL2 off the GICv5 registers. + */ + if (vgic_model !=3D KVM_DEV_TYPE_ARM_VGIC_V3) + vgic_model =3D 0; + hyp_vm->kvm.arch.vgic.vgic_model =3D vgic_model; =20 /* No restrictions for non-protected VMs. */ if (!kvm_vm_is_protected(kvm)) { --=20 2.39.5 From nobody Sat Oct 24 20:15:28 2026 Received: from mta1.migadu.com (out-148.mta1.migadu.com [95.215.58.148]) (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 A6C013C0607 for ; Sun, 11 Oct 2026 14:36:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.148 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791729422; cv=none; b=oPyCTtoit6G8mivjNaL2Jy5gtgUf3OFFcUCymffzHXuSdIORZOiK0dXSjvg/+eAYt8R6mrQq12S2PNUcjyOzKH+5qkzArA4niw+cR6/1Qan/P6KaREOkFZQNPPXi1HfJcNrlqbME+UbU1U31rO0ilQos9VMhFKVf7f3y7nlzhIQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791729422; c=relaxed/simple; bh=W/CBcZgzrCyfWkw/en5F1F87whMpeCt6l2XK9zwdnwA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=VcvDdQeQtJHHY8KeYt+NMGN6KjT5/uOqN6f0HFOj39ih35cmRVSLwi/GE/fzMnbj9fD7fQ5gYlnbeUBnKMjup401WQdcgAa2+2GygN6KnTDyj3GYfyYpEvdnbpI50Xw7KVAaE1JTt9DTKTDvvBDxqMY9xzy5MflMN9cJ9kO99z4= 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=u9WvkEiJ; arc=none smtp.client-ip=95.215.58.148 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="u9WvkEiJ" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=W/CBcZgzrCyfWkw/en5F1F87whMpeCt6l2XK9zwdnwA=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1791729416; v=1; x=1792334216; b=u9WvkEiJYfVKNfKXd/Kz8sjtH/nxhG6NTWk+/gObY2YPMB9muWhzrnnQ087g/ov4il8fdUoh e8qv+nva89gGEnY27NsciUFWaQpqkPCdBW1B9mCIv6DWDnxatsggwBphqpnKwXTfj+nCKivfiyn LPfQKs+Zw1GcfEiYsNmB5cXU= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id d34b3f25e440f7c0; Sun, 11 Oct 2026 14:36:56 +0000 X-Mizu-Trace-ID: d34b3f25e440f7c0 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, vdonnefort@google.com, qperret@google.com, Sascha.Bischoff@arm.com, steven.price@arm.com, tabba@google.com Subject: [PATCH v2 4/5] KVM: arm64: vgic: Do not access the GICv5 CPU interface from EL1 Date: Sun, 11 Oct 2026 15:36:47 +0100 Message-Id: <20261011143648.211337-5-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20261011143648.211337-1-fuad.tabba@linux.dev> References: <20261011143648.211337-1-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: quoted-printable Content-Type: text/plain; charset="utf-8" can_access_vgic_from_kernel() excludes only the GICv3 system register interface, so on a native GICv5 system without FEAT_GCIE_LEGACY it returns true under nVHE. The kernel then saves and restores the CPU interface from EL1, where ICH_VMCR_EL2 and the ICH_PPI_* registers are UNDEFINED, so running a vCPU oopses the host. The nVHE world switch already does that work at EL2. Require VHE for GICv5 as for GICv3. Fixes: 9b8e3d4ca0e73 ("KVM: arm64: gic-v5: Implement GICv5 load/put and sav= e/restore") Reviewed-by: Sascha Bischoff Signed-off-by: Fuad Tabba --- arch/arm64/kvm/vgic/vgic.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c index b25303d9919fd..da72779d3b3ee 100644 --- a/arch/arm64/kvm/vgic/vgic.c +++ b/arch/arm64/kvm/vgic/vgic.c @@ -1045,11 +1045,15 @@ static void vgic_flush_lr_state(struct kvm_vcpu *vc= pu) static inline bool can_access_vgic_from_kernel(void) { /* - * GICv2 can always be accessed from the kernel because it is - * memory-mapped, and VHE systems can access GICv3 EL2 system - * registers. + * GICv3 and GICv5 drive the CPU interface through EL2 system + * registers, so only VHE reaches them from the kernel. GICv2 is + * memory-mapped and always reachable. */ - return !static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif) || has= _vhe(); + if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif) || + kvm_vgic_global_state.type =3D=3D VGIC_V5) + return has_vhe(); + + return true; } =20 static inline void vgic_save_state(struct kvm_vcpu *vcpu) --=20 2.39.5 From nobody Sat Oct 24 20:15:28 2026 Received: from mta1.migadu.com (out-157.mta1.migadu.com [95.215.58.157]) (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 71CBA457E45 for ; Sun, 11 Oct 2026 14:37:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.157 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791729439; cv=none; b=PErdStoREO33sZguA2EqiPVoxjP2aRNGGiBMvQw6WmcG27Tv1nWn8j9mdMyrd4CSf4SYBLbp/rSQ7UZNZ0YvF6XEehJXkkaqHxIuuwS7IOCLoO70dL3G2f8HcxaTpFRxPq/n9ovANgQt1S43gnN4EaMM9J7GuTcqhbooTM1Ys2I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791729439; c=relaxed/simple; bh=sXzD5OweRtbt4uiu9AwJiDOee0ALx9j8z+8yBBR+qWw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=bBH0PcpSibVjrMcpweLLb2X9v1CsgIwroIhTGexUsT3Rixr7g2al582IoFcDSG5QMLA7rJWQCk8e8udhhky7VoT0rIvOimDZ4ZA7cmksdNmdH4mUuL21xnyIGRyaxaFWvE+PSBUoQ6PBTEJIurvkiwwoamNKD3m7GtWrlasqDpI= 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=ZYz9clKn; arc=none smtp.client-ip=95.215.58.157 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="ZYz9clKn" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=sXzD5OweRtbt4uiu9AwJiDOee0ALx9j8z+8yBBR+qWw=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1791729436; v=1; x=1792334236; b=ZYz9clKnNdWI/O5o2aGxh+/ZoVtKOw/ugM8zfFc5swbuzadQsfIu/a7k5vywGkpLxCcuKx32 WwwdICmG1O2qvh6FZv0prANzB/ZP+W/Caz5K8/NRk9ILAzEoyMEsKN/iWbVkFM2dQv0IpZoBoC2 kHnYapCql8DBYDDnE5GV7WxU= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id f4561a6c30307f5b; Sun, 11 Oct 2026 14:37:16 +0000 X-Mizu-Trace-ID: f4561a6c30307f5b 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, vdonnefort@google.com, qperret@google.com, Sascha.Bischoff@arm.com, steven.price@arm.com, tabba@google.com Subject: [PATCH v2 5/5] KVM: arm64: Fix stale VGICv3 comments in the nVHE world switch Date: Sun, 11 Oct 2026 15:36:48 +0100 Message-Id: <20261011143648.211337-6-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20261011143648.211337-1-fuad.tabba@linux.dev> References: <20261011143648.211337-1-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: quoted-printable Content-Type: text/plain; charset="utf-8" __hyp_vgic_save_state() and __hyp_vgic_restore_state() handle GICv5 as well as GICv3, but their comments name VGICv3 only. Reviewed-by: Sascha Bischoff Signed-off-by: Fuad Tabba --- arch/arm64/kvm/hyp/nvhe/switch.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/swi= tch.c index 7318e3e6a5f36..6b9e20f6b31b3 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -110,7 +110,7 @@ static void __deactivate_traps(struct kvm_vcpu *vcpu) write_sysreg(__kvm_hyp_host_vector, vbar_el2); } =20 -/* Save VGICv3 state on non-VHE systems */ +/* Save vgic state on non-VHE systems */ static void __hyp_vgic_save_state(struct kvm_vcpu *vcpu) { if (vgic_is_v5(kern_hyp_va(vcpu->kvm))) { @@ -125,7 +125,7 @@ static void __hyp_vgic_save_state(struct kvm_vcpu *vcpu) } } =20 -/* Restore VGICv3 state on non-VHE systems */ +/* Restore vgic state on non-VHE systems */ static void __hyp_vgic_restore_state(struct kvm_vcpu *vcpu) { if (vgic_is_v5(kern_hyp_va(vcpu->kvm))) { --=20 2.39.5