From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 64E853E123F; Tue, 6 Oct 2026 08:30:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791275437; cv=none; b=Iz0qH0pHX4gSJajW1WFtGM/QpFMLNZn4yi5kbDz2xMyeNjYDHCJMUNiPYJbNKFDhFt8cjfy7Iq/rEVOjkxckqVMPdwfg2hGoxSyGiogRy3+dMVP9r7v46/uQYfwPWRhDzFmcLtDxSIsfKNV+hh5MKSl4l0l/oukAKaHRLm383Fc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791275437; c=relaxed/simple; bh=S104aBvWvcjDpwSAuYRp94+JN5ILa7zOtEE62s70xcQ=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=CIT/BJUCH5YGTK1j7MzJkEsBcSTFAMRA7d1904w9x8gkgp/1AP+3MtaxJ2Hx2jfMnfreOCITWHb11Tt3Tqcro3W5eoQGDhEtJl26seSuXCPf4Xe58aK3wzLIN7+kmYjPqnEUWUAOCimeWh+jirVcCeDPK5+MDPru/POuWhlv24E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LG0K2CBh; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LG0K2CBh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8D111F000FF; Tue, 6 Oct 2026 08:30:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791275435; bh=ezI8UiBBWAdumn89F3u9bJA9IULMvyJf/Nv4niiHgUs=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=LG0K2CBhlcbzq74ehpntcnmQwYNzuCCtfG+S7uiSuMlqrCskcf1ruTLjEnZaz4X6S whbuXKS0axRYVR2GNMEHt2ede3C6LSO1PJ8oajSdnoJtYGOzcHdJHT7CMEghiecNoO d3ejR3sDbl8CK8v8Bj7LkBM493PrlFJ3BXyN+HvCLsX8RNaVIAzTBylD0JJW1DmXgN srl5le4e32gBvHR/72yX9/bDldGG/cQVZgKMGpHtbXaZ0oxJK7bjaNlqoMaRbCHuBE sVQYVu/Qcsbz05wIv7TB/KMWF1ZS2tKWrk2ct+I49euc+5QexvJ7OkpdwnbsT7jrKp k4vWQ1UZQgDXg== Received: from sofa.misterjones.org ([185.219.108.64] helo=lobster-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1xE0ZE-0000000HLLe-26HQ; Tue, 06 Oct 2026 08:30:33 +0000 Date: Tue, 06 Oct 2026 09:33:39 +0100 Message-ID: <87cxtn2pp8.wl-maz@kernel.org> From: Marc Zyngier To: Suzuki K Poulose Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, will@kernel.org, catalin.marinas@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, steven.price@arm.com, aneesh.kumar@kernel.org, oupton@kernel.org, gshan@redhat.com, joey.gouly@arm.com, tabba@google.com, yuzenghui@huawei.com, linux-coco@lists.linux.dev, gankulkarni@os.amperecomputing.com, sdonthineni@nvidia.com, alpergun@google.com, fj0570is@fujitsu.com, WeiLin.Chang@arm.com, lpieralisi@kernel.org, enju.kohei@fujitsu.com, sudeep.holla@arm.com, jonathan.cameron@oss.qualcomm.com Subject: Re: [PATCH v22 05/23] KVM: arm64: Track the type of VM in kvm_arch In-Reply-To: <20261005090754.2140522-6-suzuki.poulose@arm.com> References: <20261005090754.2140522-1-suzuki.poulose@arm.com> <20261005090754.2140522-6-suzuki.poulose@arm.com> 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: linux-kernel@vger.kernel.org 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: suzuki.poulose@arm.com, kvm@vger.kernel.org, kvmarm@lists.linux.dev, will@kernel.org, catalin.marinas@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, steven.price@arm.com, aneesh.kumar@kernel.org, oupton@kernel.org, gshan@redhat.com, joey.gouly@arm.com, tabba@google.com, yuzenghui@huawei.com, linux-coco@lists.linux.dev, gankulkarni@os.amperecomputing.com, sdonthineni@nvidia.com, alpergun@google.com, fj0570is@fujitsu.com, WeiLin.Chang@arm.com, lpieralisi@kernel.org, enju.kohei@fujitsu.com, sudeep.holla@arm.com, jonathan.cameron@oss.qualcomm.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, 05 Oct 2026 10:07:36 +0100, Suzuki K Poulose wrote: > > KVM arm64 has different types of VMs with all the different modes in which > the hypervisor code can be run. e.g., VHE, nVHE, pKVM etc. Then there is > protected VM and normal VMs with pKVM. We might soon add other types, > e.g., Arm CCA Realm. So in an effort to make the handling of these > different types of VMs a bit more friendly to the eyes, add a VM flavor to > the kvm_arch and we could then add handlers for different operations based > on the VM type. > > Keep the flavor initialisation at the beginning to allow for the detection > early enough and fail out on any unsupported requests. > > With that, add wrappers for checking the "type" of a VM and replace the > existing users with the new wrappers. > > Given we already have the construct of "kvm_vm_is_protected" in the core > KVM code, use that for all confidential compute guests including Realms > that we are about to add. Adds __VM_PROTECTED marker vm flavor to draw the > boundary for "protected VMs". In later patches, we would add Realm VMs, > which would also be classified as protected. > > Add a explicit helper to detect if a given VM is a "protected" VM under pKVM. > Change the existing users that precisely want to check the VM type. These > include : > - kvm_arch_prepare_memory_region - For preventing memslot changes after > pVM creation. > > All the others are retained as a wider check for confidential guest VMs. > These are: > - kvm_vm_ioctl_set_counter_offset - For disallowing timer offset > configuration > - io_mem_abort for dabt handling without valid syndrome information > > Both of which are true for Realms too. > > Realms support is restricted to VHE host and thus "kvm_vm_is_protected()" > checks in the pkvm hyp specific code doesn't need to change, as the only > protected guests it deals with is "protected pKVM" guests. To tighten this > init_pkvm_hyp_vm() restricts the hyp copy of the vm_flavor to the ones it > supports. > > vcpu_is_protected() usage from nVHE hyp code is tricky, as we need to > convert the vcpu->kvm to the HYP VA before checking the flavor. This > involves kern_hyp_va() usage in asm/kvm_host.h. To avoid build breaks, > include asm/kvm_mmu.h to arm64/kvm/mmio.c. > > While at it move the psci_version around to keep the structure packed. > > Suggested-by: Marc Zyngier > Tested-by: Gavin Shan > Signed-off-by: Suzuki K Poulose > --- > Changes since v21: > - Drop kern_hyp_va() and restrict nvhe code to always use vcpu_is_protected_pkvm() > - Drop kvm_vm_is_unprotected_pkvm() and open code the check > - Move psci_version field in kvm_arch around to keep the structure packed > --- > arch/arm64/include/asm/kvm_host.h | 42 +++++++++++++++++++++++--- > arch/arm64/include/asm/kvm_pkvm.h | 4 +-- > arch/arm64/kvm/arm.c | 33 ++++++++++++++++---- > arch/arm64/kvm/hyp/include/nvhe/pkvm.h | 2 +- > arch/arm64/kvm/hyp/nvhe/pkvm.c | 6 +++- > arch/arm64/kvm/hyp/nvhe/switch.c | 4 +-- > arch/arm64/kvm/hyp/nvhe/timer-sr.c | 2 +- > arch/arm64/kvm/mmio.c | 1 + > arch/arm64/kvm/mmu.c | 2 +- > arch/arm64/kvm/pkvm.c | 6 ++-- > 10 files changed, 79 insertions(+), 23 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 286489a69dff5..dedb5df15a803 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -257,7 +257,6 @@ struct kvm_protected_vm { > pkvm_handle_t handle; > struct kvm_hyp_memcache teardown_mc; > struct kvm_hyp_memcache stage2_teardown_mc; > - bool is_protected; > bool is_created; > > /* > @@ -306,9 +305,22 @@ enum fgt_group_id { > __NR_FGT_GROUP_IDS__ > }; > > +enum kvm_arm_vm_flavor { > + VM_NVHE, > + VM_VHE, > + VM_PKVM, /* Normal guests on pKVM */ > + MARKER(__VM_PROTECTED), > + VM_PROTECTED_PKVM, /* Protected VM */ > + VM_FLAVOR_MAX > +}; > + > struct kvm_arch { > struct kvm_s2_mmu mmu; > > + enum kvm_arm_vm_flavor vm_flavor; > + /* Mandated version of PSCI */ > + u32 psci_version; > + > /* > * Fine-Grained UNDEF, mimicking the FGT layout defined by the > * architecture. We track them globally, as we present the > @@ -332,9 +344,6 @@ struct kvm_arch { > /* Timers */ > struct arch_timer_vm_data timer_data; > > - /* Mandated version of PSCI */ > - u32 psci_version; > - > /* Protects VM-scoped configuration data */ > struct mutex config_lock; > > @@ -1504,9 +1513,32 @@ struct kvm *kvm_arch_alloc_vm(void); > > #define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS_RANGE > > -#define kvm_vm_is_protected(kvm) (is_protected_kvm_enabled() && (kvm)->arch.pkvm.is_protected) > +#define kvm_vm_is_protected(kvm) ((kvm)->arch.vm_flavor >= __VM_PROTECTED) > > +#ifdef __KVM_NVHE_HYPERVISOR__ > +/* > + * Accessing vcpu->kvm from nVHE hyp stub is tricky, as we need to convert the > + * pointer to the hyp VA. With pKVM, the nVHE code runs with the hyp_vcpu, > + * which is populated correctly. Always vcpu_is_protected_pkvm(), which is Always *use*? > + * gated on is_protected_kvm_enabled(). > + */ > +#define vcpu_is_protected(vcpu) BUILD_BUG_ON(1) > +#else > #define vcpu_is_protected(vcpu) kvm_vm_is_protected((vcpu)->kvm) > +#endif > + > +#define kvm_vm_is_protected_pkvm(kvm) \ > + (is_protected_kvm_enabled() && ((kvm)->arch.vm_flavor == VM_PROTECTED_PKVM)) > +/* > + * Rely on is_protected_kvm_enabled() check in kvm_vm_is_protected_pkvm() to > + * make sure the vcpu->kvm is always valid VA in the context > + */ > +#define vcpu_is_protected_pkvm(vcpu) \ > + ({ \ > + struct kvm *__kvm = READ_ONCE((vcpu)->kvm); \ > + \ > + (__kvm && kvm_vm_is_protected_pkvm(__kvm)); \ > + }) But why do we have to have this pkvm-specific stuff? I thought we had established it is not necessary in [1]. I really want to avoid any backend-specific helper, as it really gets in the way of maintainability. M. [1] https://lore.kernel.org/r/86pkxs2npx.wl-maz@kernel.org -- Jazz isn't dead. It just smells funny.