From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: Fuad Tabba <fuad.tabba@linux.dev>
Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, maz@kernel.org,
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, 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 v23 13/14] KVM: arm64: Mandate VGIC v3 for pKVM VMs and Realms
Date: Thu, 8 Oct 2026 09:51:56 +0100 [thread overview]
Message-ID: <4cdd882b-832f-4968-9838-dcc29a899121@arm.com> (raw)
In-Reply-To: <CA+EHjTy_1EekD472UH=CDSpC7oksdy3eS8AP0rPxKkhQ_PyXdg@mail.gmail.com>
On 07/10/2026 14:45, Fuad Tabba wrote:
> Hi Suzuki,
>
> On Wed, 07 Oct 2026 08:35:36 +0100, Suzuki K Poulose
> <suzuki.poulose@arm.com> wrote:
>> pKVM does not trust the host. Realm VMs follow a similar trust model, with
>> the Realm Management Monitor owning the protected state instead of the
>> host. Add a helper to identify VMs that run under a host-distrusting
>> hypervisor.
>
> When I reviewed this in v21, the Realm patches that use this came
> later in the same series. Without them, kvm_vm_hyp_is_distrusting() is
> true exactly when is_protected_kvm_enabled() is, and protected mode
> already doesn't register a GICv2, so this patch doesn't change
> anything on its own. Should it move to the series that adds Realms?
But the second part of the changes are required for pKVM today, right ?
and you requested that here. The check as such is useful, except that
it is using kvm_vm_hyp_is_distrusting() rather than
is_protected_kvm_enabled(). I don't see this as a problem as this is
not a hotpath anyway.
https://lore.kernel.org/all/CA+EHjTzKjjEuAuoOuzGG0uKyVZE-r+CEreca2H2kEQYuRPpgUw@mail.gmail.com
Cheers
Suzuki>
> Cheers,
> /fuad
next prev parent reply other threads:[~2026-10-08 8:52 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-07 7:35 [PATCH v23 00/14] KVM: arm64: CCA: Add basic plumbing for Realms Suzuki K Poulose
2026-10-07 7:35 ` [PATCH v23 01/14] KVM: arm64: protected VM: Handle user writes to CNTVCT_EL0/CNTPCT_EL0 Suzuki K Poulose
2026-10-07 10:43 ` Fuad Tabba
2026-10-07 7:35 ` [PATCH v23 02/14] KVM: arm64: Disable Steal time accounting for protected guests Suzuki K Poulose
2026-10-07 10:51 ` Fuad Tabba
2026-10-07 13:10 ` Suzuki K Poulose
2026-10-07 7:35 ` [PATCH v23 03/14] KVM: arm64: Include kvm_emulate.h in kvm/arm_psci.h Suzuki K Poulose
2026-10-07 11:00 ` Fuad Tabba
2026-10-07 7:35 ` [PATCH v23 04/14] KVM: arm64: Avoid including linux/kvm_host.h in kvm_pgtable.h Suzuki K Poulose
2026-10-07 7:35 ` [PATCH v23 05/14] KVM: arm64: Track the type of VM in kvm_arch Suzuki K Poulose
2026-10-07 7:35 ` [PATCH v23 06/14] KVM: arm64: Don't call vcpu_set_pauth_traps for pKVM host Suzuki K Poulose
2026-10-07 11:07 ` Fuad Tabba
2026-10-07 7:35 ` [PATCH v23 07/14] KVM: arm64: Refactor the vcpu_load to allow for VM specific callbacks Suzuki K Poulose
2026-10-07 11:12 ` Fuad Tabba
2026-10-07 7:35 ` [PATCH v23 08/14] KVM: arm64: Add vcpu load/put call backs for flavors Suzuki K Poulose
2026-10-07 11:18 ` Fuad Tabba
2026-10-07 7:35 ` [PATCH v23 09/14] KVM: arm64: Consolidate stage2 unmap range into kvm_stage2_unmap_range Suzuki K Poulose
2026-10-07 11:23 ` Fuad Tabba
2026-10-07 7:35 ` [PATCH v23 10/14] KVM: arm64: Add VM specific callback for S2 MMU operations Suzuki K Poulose
2026-10-07 11:38 ` Fuad Tabba
2026-10-07 7:35 ` [PATCH v23 11/14] KVM: arm64: Use a local kvm pointer in kvm_handle_guest_abort() Suzuki K Poulose
2026-10-07 7:35 ` [PATCH v23 12/14] KVM: arm64: Abstract out memory abort handling Suzuki K Poulose
2026-10-07 13:45 ` Fuad Tabba
2026-10-07 7:35 ` [PATCH v23 13/14] KVM: arm64: Mandate VGIC v3 for pKVM VMs and Realms Suzuki K Poulose
2026-10-07 13:45 ` Fuad Tabba
2026-10-08 8:51 ` Suzuki K Poulose [this message]
2026-10-08 11:17 ` Fuad Tabba
2026-10-07 7:35 ` [PATCH v23 14/14] KVM: arm64: Prevent unsupported vcpu features for VM types Suzuki K Poulose
2026-10-07 14:19 ` Fuad Tabba
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