From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id AA87C415F1F; Mon, 3 Aug 2026 15:18:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785770306; cv=none; b=QelX2Jrj68tQ4c7hEhIjxRDuUF6kVhQj1z3by1nv/S6uA1PyXj3R+orERlA3Q3IwbajuwS4sFhgs/H4GEje36XK22nKexOTbFr1ToiycJKcDSUAYN/giFnhVfHIxgp9KvX5iyB12hhwcmS60WJcI8Pn4ESN74cuVNE2yY5xmsmo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785770306; c=relaxed/simple; bh=a5G5LMPPyNBg/dAf4FAYnm9izzvFgYrpS6qSIas4tHA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=hSzZA/CjFZr5PV93lavOQZbfrJi21CNEaH7AMftfEy8aR59llgOWt32t424fiB3SmU9aCFw1RmlxGi/1bF067K6G+XEYKwydSuJT4XtG9dp30CJyP4IRLhaCrB01FFbx9iC7djjtiSRiTpsu4Vpt1eiwaZChh4wGqfzrdjUwxZs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=P/EjJyab; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="P/EjJyab" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 42554143D; Mon, 3 Aug 2026 08:18:19 -0700 (PDT) Received: from [10.1.25.28] (e122027.cambridge.arm.com [10.1.25.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8F7343F66F; Mon, 3 Aug 2026 08:18:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1785770303; bh=a5G5LMPPyNBg/dAf4FAYnm9izzvFgYrpS6qSIas4tHA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=P/EjJyabE9lK32euTx1Wi9058FfNuSTH0MKFDFNkN+UG8A8xu4flKej/XWEImcgKK gUmWZDMAAlZyiQqrXlUaBmnNnsFkclTihe0Qx9fOzWmpPYsPFeOYYcsmMBJPuq5Q3E YxIzxM++5YQhYrS+i1gT99OSEKDffNCIVgT7C+dk= Message-ID: Date: Mon, 3 Aug 2026 16:18:14 +0100 Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v15 19/37] KVM: arm64: CCA: Activate realms on first vCPU run To: Marc Zyngier Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, Catalin Marinas , Will Deacon , James Morse , Oliver Upton , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . V" , Emi Kisanuki , Vishal Annapurve , WeiLin.Chang@arm.com, Lorenzo Pieralisi References: <20260715142841.80544-1-steven.price@arm.com> <20260715142841.80544-20-steven.price@arm.com> <8633wvcrqr.wl-maz@kernel.org> From: Steven Price Content-Language: en-GB In-Reply-To: <8633wvcrqr.wl-maz@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 03/08/2026 13:29, Marc Zyngier wrote: > On Wed, 15 Jul 2026 15:28:21 +0100, > Steven Price wrote: >> >> Use kvm_arch_vcpu_run_pid_change() to check if this is the first time >> the realm guest has run. If this is the first run then activate the >> realm. >> >> Signed-off-by: Steven Price >> >> --- >> Changes since v12: >> * Fix commit message >> * Change realm_state checks to be >= REALM_STATE_ACTIVE to avoid a dead >> guest being revived by kvm_activate_realm(). >> --- >> arch/arm64/include/asm/kvm_rmi.h | 1 + >> arch/arm64/kvm/arm.c | 6 +++++ >> arch/arm64/kvm/rmi.c | 45 ++++++++++++++++++++++++++++++-- >> 3 files changed, 50 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm64/include/asm/kvm_rmi.h b/arch/arm64/include/asm/kvm_rmi.h >> index 5461c49bea4d..5cb99c187202 100644 >> --- a/arch/arm64/include/asm/kvm_rmi.h >> +++ b/arch/arm64/include/asm/kvm_rmi.h >> @@ -96,6 +96,7 @@ void kvm_init_rmi(void); >> u32 kvm_rmm_ipa_limit(void); >> >> int kvm_init_realm(struct kvm *kvm); >> +int kvm_activate_realm(struct kvm *kvm); >> void kvm_destroy_realm(struct kvm *kvm); >> int kvm_realm_teardown_stage2(struct kvm *kvm); >> void kvm_destroy_rec(struct kvm_vcpu *vcpu); >> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c >> index 534d33b7c67a..df33322b8fea 100644 >> --- a/arch/arm64/kvm/arm.c >> +++ b/arch/arm64/kvm/arm.c >> @@ -1034,6 +1034,12 @@ int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu) >> return ret; >> } >> >> + if (kvm_is_realm(vcpu->kvm)) { >> + ret = kvm_activate_realm(kvm); >> + if (ret) >> + return ret; >> + } >> + >> mutex_lock(&kvm->arch.config_lock); >> set_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &kvm->arch.flags); >> mutex_unlock(&kvm->arch.config_lock); >> diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c >> index 94776a9262c9..53b5b18f2275 100644 >> --- a/arch/arm64/kvm/rmi.c >> +++ b/arch/arm64/kvm/rmi.c >> @@ -687,7 +687,7 @@ static int realm_set_ipa_state(struct kvm_vcpu *vcpu, >> return ret; >> } >> >> -static int __maybe_unused realm_ensure_created(struct kvm *kvm) >> +static int realm_ensure_created(struct kvm *kvm) >> { >> lockdep_assert_held(&kvm->arch.config_lock); >> >> @@ -793,7 +793,7 @@ int noinstr kvm_rec_enter(struct kvm_vcpu *vcpu) >> return ret; >> } >> >> -static int __maybe_unused kvm_create_rec(struct kvm_vcpu *vcpu) >> +static int kvm_create_rec(struct kvm_vcpu *vcpu) >> { >> struct user_pt_regs *vcpu_regs = vcpu_gp_regs(vcpu); >> unsigned long mpidr = kvm_vcpu_get_mpidr_aff(vcpu); >> @@ -893,6 +893,47 @@ void kvm_destroy_rec(struct kvm_vcpu *vcpu) >> rec->rec_page = NULL; >> } >> >> +int kvm_activate_realm(struct kvm *kvm) >> +{ >> + struct realm *realm = &kvm->arch.realm; >> + struct kvm_vcpu *vcpu; >> + unsigned long i; >> + int ret; >> + >> + if (kvm_realm_state(kvm) >= REALM_STATE_ACTIVE) >> + return 0; >> + >> + if (!irqchip_in_kernel(kvm)) { >> + /* Userspace irqchip not yet supported with realms */ >> + return -EOPNOTSUPP; >> + } > > This could race with the irqchip being created on another CPU. Also, > an irqchip being in kernel doesn't mean it is ready, and I suspect > you also need to check that it has been initialised. Good point - moving the config_lock up and checking vgic_initialized() makes sense. >> + >> + guard(mutex)(&kvm->arch.config_lock); >> + /* Check again with the lock held */ >> + if (kvm_realm_state(kvm) >= REALM_STATE_ACTIVE) >> + return 0; >> + >> + ret = realm_ensure_created(kvm); >> + if (ret) >> + return ret; >> + >> + /* Mark state as dead in case we fail */ >> + kvm_set_realm_state(kvm, REALM_STATE_DEAD); >> + >> + kvm_for_each_vcpu(i, vcpu, kvm) { >> + ret = kvm_create_rec(vcpu); >> + if (ret) >> + return ret; >> + } > > If the realm is dead, shouldn't the KVM view of death apply as well? Indeed that would be a good improvement. I'll change these error paths to include a kvm_vm_dead() call. Thanks, Steve >> + >> + ret = rmi_realm_activate(virt_to_phys(realm->rd)); >> + if (ret) >> + return -ENXIO; >> + >> + kvm_set_realm_state(kvm, REALM_STATE_ACTIVE); >> + return 0; >> +} >> + >> void kvm_destroy_realm(struct kvm *kvm) >> { >> struct realm *realm = &kvm->arch.realm; > > Thanks, > > M. >