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Sat, 17 Oct 2026 16:24:12 +0000 Date: Sat, 17 Oct 2026 17:24:11 +0100 Message-ID: <865wz01ej8.wl-maz@kernel.org> From: Marc Zyngier To: Fuad Tabba Cc: oupton@kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, 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: Re: [PATCH v3 1/5] KVM: arm64: Reject the GICv5 CPU interface hypercalls under pKVM In-Reply-To: <20261012161524.4016464-2-fuad.tabba@linux.dev> References: <20261012161524.4016464-1-fuad.tabba@linux.dev> <20261012161524.4016464-2-fuad.tabba@linux.dev> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: fuad.tabba@linux.dev, oupton@kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, 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 X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Mon, 12 Oct 2026 17:15:20 +0100, Fuad Tabba wrote: > > __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 interface") > 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, > > MARKER(__KVM_HOST_SMCCC_FUNC_MIN_PKVM), > > @@ -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, > > MARKER(__KVM_HOST_SMCCC_FUNC_PKVM_ONLY), > > diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-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[] = { > 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), > > HANDLE_FUNC(__kvm_adjust_pc), > @@ -932,8 +934,6 @@ static const hcall_t host_hcall[] = { > 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), > > HANDLE_FUNC(__pkvm_host_share_hyp), > HANDLE_FUNC(__pkvm_host_unshare_hyp), In order to minimise the number of conflicts while merging this, I've dropped the last two hunks that only serve a cosmetic purpose. Same thing for the following patch. Thanks, M. -- Without deviation from the norm, progress is not possible.