From nobody Sat Oct 24 20:42:35 2026 Received: from mta0.migadu.com (out-95.mta0.migadu.com [91.218.175.95]) (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 6FEDB4A5EB4 for ; Mon, 12 Oct 2026 16:15:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.95 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791821743; cv=none; b=erP+Zk0IdylAwWbYGgpHXlo8XKfWgFv/Vbye37TD6RPibIzOzY4lEeSPj7TJLVLMNoMtHrV2XADmH3a0kBcHoHsMCoTA+/s1sZ9z9cLeLl4wI5VgaONdEbvKdg4ojYf+pofhLKmCznj9ASbuASVk+pQPhWyCqX+w7qdEmpm2u44= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791821743; c=relaxed/simple; bh=8gCu4rhChE8WNWy4D5zHkBnBqB6ebjExaCX/l1sJrV4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=WVr/hse1TGA4lYP9woVWhgmIYofLtLE7agxAIFH+XVF7tHyR71ftMbfWbN9Cs/sbwpOwYJfLMQftkTdjSj7xezkyVOG5qxVRd5hy1W+rq2MH+u0XcwHtPKwTRgA928+rUKG8XCxFte8F/uqX5P/1HlS7y5Wsu1AdB841TBIho6E= 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=YMmjyTND; arc=none smtp.client-ip=91.218.175.95 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="YMmjyTND" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=8gCu4rhChE8WNWy4D5zHkBnBqB6ebjExaCX/l1sJrV4=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1791821739; v=1; x=1792426539; b=YMmjyTND2tmeKbrXTACknnhjDs9WR9bPA0EZhhEgNanjxTRDbg6vjc/8KfWxMzR+DMH24JtC Bl6vbL1hxFgBFl9b6CCiWE85UQrV3EIW84GhWHzqKw4z9WFGj28PMbBSXGXF94LVJDn2ZIzvYlA lMYiHSIFWb+MqF1+/nzba0g4= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 78425c6ac2fc2bac; Mon, 12 Oct 2026 16:15:38 +0000 X-Mizu-Trace-ID: 78425c6ac2fc2bac 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 v3 1/5] KVM: arm64: Reject the GICv5 CPU interface hypercalls under pKVM Date: Mon, 12 Oct 2026 17:15:20 +0100 Message-Id: <20261012161524.4016464-2-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20261012161524.4016464-1-fuad.tabba@linux.dev> References: <20261012161524.4016464-1-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") Reviewed-by: Suzuki K Poulose Signed-off-by: Fuad Tabba --- 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 20:42:35 2026 Received: from mta0.migadu.com (out-99.mta0.migadu.com [91.218.175.99]) (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 C33484AB3A3 for ; 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arc=none smtp.client-ip=91.218.175.99 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="Onbftcie" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=MS6Ai7kYsGDBUhWOJOqxT06KTaz3wq2XFRTVLCJ+Ee0=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1791821741; v=1; x=1792426541; b=OnbftcieTnKywjJLyKVZOdM8BTW+wixQ/5LsZ8xU5M13j0njVoFzb6/xQzK1PNoh3BRzxViO /SO/h5jt/qcY3Fl5cDLtwMaylPbtg2aQ7WuMbILvDFFXGXqbnRHrhRJuS2dWLPbeQfBcIIIDe9E ef6ltG42wXQKwRA/Rlo4H7g8= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 35b98ee5bcb724f9; Mon, 12 Oct 2026 16:15:41 +0000 X-Mizu-Trace-ID: 35b98ee5bcb724f9 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 v3 2/5] KVM: arm64: Reject the stage-2 flush hypercalls under pKVM Date: Mon, 12 Oct 2026 17:15:21 +0100 Message-Id: <20261012161524.4016464-3-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20261012161524.4016464-1-fuad.tabba@linux.dev> References: <20261012161524.4016464-1-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/ Reviewed-by: Suzuki K Poulose Signed-off-by: Fuad Tabba --- 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 20:42:35 2026 Received: from mta0.migadu.com (out-104.mta0.migadu.com [91.218.175.104]) (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 B155B4A9D49 for ; Mon, 12 Oct 2026 16:15:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.104 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791821746; cv=none; b=JtkEYTwW+HdnifelTXrBmlWz6/8XBRIrjA51v2QBY2zrwc4BtQg9NwxqhVgqvHTy0a9MDYw//KY4b69RRoZ81Pt8eUdoSuxTpC0MkglXyuIlcJhfUE9BgeUlUbqE4BGkiLhpYK4X2PO+Zp/Dd1r7Cj2Ddjtnm3bA1cbYJ8ZxkMw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791821746; c=relaxed/simple; bh=AlgWXXlL64ISukcpD4mn3Z6rAwsBvHEkYXTdPZYRaJc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Njaw067zJQAzTairft7S11UF/Y0/+b532etfXQ73QaQMoZUWpP17aYd0STuAkpOHYastgi4CRG/YnT7wlofjwipWYmMIaH2st1sB5vGXwXLNpIcsHp9VsavwDgfzn0vfjQScgEISIlbWUzPmuoH/NVmgYV7fxAZAfR6h/eNClEI= 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=HCuaq9+v; arc=none smtp.client-ip=91.218.175.104 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="HCuaq9+v" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=AlgWXXlL64ISukcpD4mn3Z6rAwsBvHEkYXTdPZYRaJc=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1791821742; v=1; x=1792426542; b=HCuaq9+v5ALKLNCbRSNr8Z653I6mdvCxrk9bQmp8DV03vFB/P1Nc+Ab/75Mo573yKvazsQgW yTVC6k+z5RDOpY8I7NY22GD2A53NVDVjjDcxTX/2PCXa7VaO1AftYXw1cF8k2/v4Gs1gGsshkVd UlstUEETRWPCPBw1fu4LWkSk= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id da1724085719ce2e; Mon, 12 Oct 2026 16:15:42 +0000 X-Mizu-Trace-ID: da1724085719ce2e 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 v3 3/5] KVM: arm64: Validate the host-provided vgic model in pKVM Date: Mon, 12 Oct 2026 17:15:22 +0100 Message-Id: <20261012161524.4016464-4-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20261012161524.4016464-1-fuad.tabba@linux.dev> References: <20261012161524.4016464-1-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") Reviewed-by: Suzuki K Poulose Signed-off-by: Fuad Tabba --- 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 20:42:35 2026 Received: from mta1.migadu.com (out-19.mta1.migadu.com [95.215.58.19]) (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 2C6D04ACC68 for ; Mon, 12 Oct 2026 16:15:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.19 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791821746; cv=none; b=E8aX3YKUZS3TZnlUBnOIaOA3Oq2kumjwiTjX1UeWwmT2Q/6CRNTqOpCXs+r3UH67pPyjZ7W6k9zWVfI/cKS1RTKHVnR9OeH/j7jOOQwVzrP1oj0vrsWdh6N/0D9UynP2KPMvohm6Q0M9WIP66npaDNftOeKf/6OkQV0TA2ZoXZM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791821746; c=relaxed/simple; bh=o7DFXgB7gt6JJSGpUWCP61Fwkd7G9jFVrpvO58x0yzY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=PawGzLmHHXj2Q+j/66KaC7W/JMWcJWe92qvDYFmuYP5vur9ShQ2rZpNPyzzaVtoGbHz52cF7mPK5ZISH8Vi9Hg6GZONQ6ybYuqumkyFX5QRQxg0lRYmbbX3HmvaZjfeuXoFa0PsP0AZsa1N8YQyC4k6T9QqigYdKG0nTL8qUs6g= 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=v1I7JqKv; arc=none smtp.client-ip=95.215.58.19 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="v1I7JqKv" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=o7DFXgB7gt6JJSGpUWCP61Fwkd7G9jFVrpvO58x0yzY=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1791821743; v=1; x=1792426543; b=v1I7JqKv0A4pu4KQCydGJ/aRNeXNNUp6kEFfLJPQSyfRH3tLXG+SDPpHrVL0S7MQQrz0Zaj8 tr25OBH8mVLd1F6fXR599w28M1QgmNHtQM7aOkr3hbC2WV/R/fYqJzunL12paHdpsWpv4oNhBpj t/W3m+mnwZQ/9WFEKyAw4Lfo= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 14a0d496e56a0a12; Mon, 12 Oct 2026 16:15:43 +0000 X-Mizu-Trace-ID: 14a0d496e56a0a12 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 v3 4/5] KVM: arm64: vgic: Do not access the GICv5 CPU interface from EL1 Date: Mon, 12 Oct 2026 17:15:23 +0100 Message-Id: <20261012161524.4016464-5-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20261012161524.4016464-1-fuad.tabba@linux.dev> References: <20261012161524.4016464-1-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() requires VHE only for 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, and running a vCPU oopses the host. The nVHE world switch already does that work at EL2. Anything that requires EL2 system registers or instructions is out of reach of a kernel running at EL1, which leaves GICv2, the one memory-mapped CPU interface. Allow GICv2 from EL1 and require VHE for everything else. Fixes: 9b8e3d4ca0e73 ("KVM: arm64: gic-v5: Implement GICv5 load/put and sav= e/restore") Suggested-by: Marc Zyngier Reviewed-by: Sascha Bischoff Signed-off-by: Fuad Tabba --- arch/arm64/kvm/vgic/vgic.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c index b25303d9919fd..fe5b14a8b1214 100644 --- a/arch/arm64/kvm/vgic/vgic.c +++ b/arch/arm64/kvm/vgic/vgic.c @@ -1045,11 +1045,10 @@ 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. + * GICv2 is memory-mapped. Every other CPU interface uses EL2 system + * registers, which only VHE can access from the kernel. */ - return !static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif) || has= _vhe(); + return has_vhe() || kvm_vgic_global_state.type =3D=3D VGIC_V2; } =20 static inline void vgic_save_state(struct kvm_vcpu *vcpu) --=20 2.39.5 From nobody Sat Oct 24 20:42:35 2026 Received: from mta0.migadu.com (out-119.mta0.migadu.com [91.218.175.119]) (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 07ABF3168E6 for ; Mon, 12 Oct 2026 16:16:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.119 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791821762; cv=none; b=AlFRJdiWrbMAwqUV6NcHbP8KOBCqYmkWNmYlE4R1Lf7JHJ7CVWw8gEtJqT6ZUumJnF2p725OuCg9PMkzzkibNlLCmbas9jhykmJn9lOTjae70ICUY85i3ssm8Ky/pZFxyOCi3UN7vzJUymHx9vgMze/f+X5hqzv2p3w0GyYIE4o= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791821762; c=relaxed/simple; bh=sXzD5OweRtbt4uiu9AwJiDOee0ALx9j8z+8yBBR+qWw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=LVzmyuBH2PGkb3dL2TWoolhPvYgxgEi7xO98TuN02XtdWz/gPP1cQ2VY61M9nI9/2tAnu4G3KFISL9kzxYSdBoN3ovuB+eOCbAe29zXJyLZUTLZBihJI1oowv9JfXj99ZULB0ePHbHuZzYeBxPj2FQwvRjfbENUvkYVXADnvSD4= 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=sjchyi9D; arc=none smtp.client-ip=91.218.175.119 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="sjchyi9D" 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=1791821758; v=1; x=1792426558; b=sjchyi9Dc7HfKs3LWQyGGgk1Owu8D9l7c4Vyxi1vdxOzv21Tlx/sWGVmfoqsVFvUJYTm61+u 7SEW/SVjtS8nXukcU8fLy109CjeWOI1mRjPXPKoN4WZ8UXSGo67xj1pn0SYaT5IlqC4+WQ9xCA/ Lc0qbc89JTiKznQlKNIaU1Lg= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id a637eb0a5d7055a4; Mon, 12 Oct 2026 16:15:58 +0000 X-Mizu-Trace-ID: a637eb0a5d7055a4 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 v3 5/5] KVM: arm64: Fix stale VGICv3 comments in the nVHE world switch Date: Mon, 12 Oct 2026 17:15:24 +0100 Message-Id: <20261012161524.4016464-6-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20261012161524.4016464-1-fuad.tabba@linux.dev> References: <20261012161524.4016464-1-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