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From: Marc Zyngier <maz@kernel.org>
To: Reiji Watanabe <reijiw@google.com>
Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	kernel-team@android.com, Will Deacon <will@kernel.org>,
	Mark Brown <broonie@kernel.org>
Subject: Re: [PATCH 06/18] KVM: arm64: Add three sets of flags to the vcpu state
Date: Fri, 10 Jun 2022 08:48:27 +0100	[thread overview]
Message-ID: <875yl93qno.wl-maz@kernel.org> (raw)
In-Reply-To: <CAAeT=FxH_rK9HT+-QLkbH9hn0LhObwCCTrbdqt0x--BgqtaK_g@mail.gmail.com>

On Thu, 09 Jun 2022 18:24:39 +0100,
Reiji Watanabe <reijiw@google.com> wrote:
> 
> I've just realized that GUEST_HAS_PTRAUTH (cflags) is used by
> hypervisor code (kvm_hyp_handle_ptrauth and get_pvm_id_aa64isar{1,2}).
> Shouldn't GUEST_HAS_PTRAUTH be handled as iflags ?
> Or, in choosing one of these three for a flag, is immutability (once
> the vcpu has run) the highest priority, followed by whether or not
> it is used by hypervisor code ?

It can be construed that most configuration flags are also input flags
to the hypervisor, as they will eventually affect its behaviour. But
the fact that a flag is immutable once the vcpu has run is a clear
criterion for a configuration flag.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: Reiji Watanabe <reijiw@google.com>
Cc: kvm@vger.kernel.org, kernel-team@android.com,
	Mark Brown <broonie@kernel.org>, Will Deacon <will@kernel.org>,
	kvmarm@lists.cs.columbia.edu,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 06/18] KVM: arm64: Add three sets of flags to the vcpu state
Date: Fri, 10 Jun 2022 08:48:27 +0100	[thread overview]
Message-ID: <875yl93qno.wl-maz@kernel.org> (raw)
In-Reply-To: <CAAeT=FxH_rK9HT+-QLkbH9hn0LhObwCCTrbdqt0x--BgqtaK_g@mail.gmail.com>

On Thu, 09 Jun 2022 18:24:39 +0100,
Reiji Watanabe <reijiw@google.com> wrote:
> 
> I've just realized that GUEST_HAS_PTRAUTH (cflags) is used by
> hypervisor code (kvm_hyp_handle_ptrauth and get_pvm_id_aa64isar{1,2}).
> Shouldn't GUEST_HAS_PTRAUTH be handled as iflags ?
> Or, in choosing one of these three for a flag, is immutability (once
> the vcpu has run) the highest priority, followed by whether or not
> it is used by hypervisor code ?

It can be construed that most configuration flags are also input flags
to the hypervisor, as they will eventually affect its behaviour. But
the fact that a flag is immutable once the vcpu has run is a clear
criterion for a configuration flag.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: Reiji Watanabe <reijiw@google.com>
Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	kernel-team@android.com, Will Deacon <will@kernel.org>,
	Mark Brown <broonie@kernel.org>
Subject: Re: [PATCH 06/18] KVM: arm64: Add three sets of flags to the vcpu state
Date: Fri, 10 Jun 2022 08:48:27 +0100	[thread overview]
Message-ID: <875yl93qno.wl-maz@kernel.org> (raw)
In-Reply-To: <CAAeT=FxH_rK9HT+-QLkbH9hn0LhObwCCTrbdqt0x--BgqtaK_g@mail.gmail.com>

On Thu, 09 Jun 2022 18:24:39 +0100,
Reiji Watanabe <reijiw@google.com> wrote:
> 
> I've just realized that GUEST_HAS_PTRAUTH (cflags) is used by
> hypervisor code (kvm_hyp_handle_ptrauth and get_pvm_id_aa64isar{1,2}).
> Shouldn't GUEST_HAS_PTRAUTH be handled as iflags ?
> Or, in choosing one of these three for a flag, is immutability (once
> the vcpu has run) the highest priority, followed by whether or not
> it is used by hypervisor code ?

It can be construed that most configuration flags are also input flags
to the hypervisor, as they will eventually affect its behaviour. But
the fact that a flag is immutable once the vcpu has run is a clear
criterion for a configuration flag.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2022-06-10  7:48 UTC|newest]

Thread overview: 141+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-28 11:38 [PATCH 00/18] KVM/arm64: Refactoring the vcpu flags Marc Zyngier
2022-05-28 11:38 ` Marc Zyngier
2022-05-28 11:38 ` Marc Zyngier
2022-05-28 11:38 ` [PATCH 01/18] KVM: arm64: Always start with clearing SVE flag on load Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-30 14:41   ` Mark Brown
2022-05-30 14:41     ` Mark Brown
2022-05-30 14:41     ` Mark Brown
2022-06-06 11:28     ` Marc Zyngier
2022-06-06 11:28       ` Marc Zyngier
2022-06-06 11:28       ` Marc Zyngier
2022-06-06 12:16       ` Mark Brown
2022-06-06 12:16         ` Mark Brown
2022-06-06 12:16         ` Mark Brown
2022-05-28 11:38 ` [PATCH 02/18] KVM: arm64: Always start with clearing SME " Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-30 14:51   ` Mark Brown
2022-05-30 14:51     ` Mark Brown
2022-05-30 14:51     ` Mark Brown
2022-05-28 11:38 ` [PATCH 03/18] KVM: arm64: Drop FP_FOREIGN_STATE from the hypervisor code Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-06-03  5:23   ` Reiji Watanabe
2022-06-03  5:23     ` Reiji Watanabe
2022-06-03  5:23     ` Reiji Watanabe
2022-06-04  8:10     ` Marc Zyngier
2022-06-04  8:10       ` Marc Zyngier
2022-06-04  8:10       ` Marc Zyngier
2022-06-07  4:47       ` Reiji Watanabe
2022-06-07  4:47         ` Reiji Watanabe
2022-06-07  4:47         ` Reiji Watanabe
2022-06-03  9:09   ` Mark Brown
2022-06-03  9:09     ` Mark Brown
2022-06-03  9:09     ` Mark Brown
2022-05-28 11:38 ` [PATCH 04/18] KVM: arm64: Move FP state ownership from flag to a tristate Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-06-03  9:14   ` Mark Brown
2022-06-03  9:14     ` Mark Brown
2022-06-03  9:14     ` Mark Brown
2022-06-06  8:41     ` Marc Zyngier
2022-06-06  8:41       ` Marc Zyngier
2022-06-06  8:41       ` Marc Zyngier
2022-06-06 10:31       ` Mark Brown
2022-06-06 10:31         ` Mark Brown
2022-06-06 10:31         ` Mark Brown
2022-06-04  8:16   ` Reiji Watanabe
2022-06-04  8:16     ` Reiji Watanabe
2022-06-04  8:16     ` Reiji Watanabe
2022-05-28 11:38 ` [PATCH 05/18] KVM: arm64: Add helpers to manipulate vcpu flags among a set Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-06-08  5:26   ` Reiji Watanabe
2022-06-08  5:26     ` Reiji Watanabe
2022-06-08  5:26     ` Reiji Watanabe
2022-06-08  6:51     ` Marc Zyngier
2022-06-08  6:51       ` Marc Zyngier
2022-06-08  6:51       ` Marc Zyngier
2022-06-09  2:25       ` Reiji Watanabe
2022-06-09  2:25         ` Reiji Watanabe
2022-06-09  2:25         ` Reiji Watanabe
2022-05-28 11:38 ` [PATCH 06/18] KVM: arm64: Add three sets of flags to the vcpu state Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-06-08 15:23   ` Fuad Tabba
2022-06-08 15:23     ` Fuad Tabba
2022-06-08 15:23     ` Fuad Tabba
2022-06-09  6:10   ` Reiji Watanabe
2022-06-09  6:10     ` Reiji Watanabe
2022-06-09  6:10     ` Reiji Watanabe
2022-06-09  7:46     ` Marc Zyngier
2022-06-09  7:46       ` Marc Zyngier
2022-06-09  7:46       ` Marc Zyngier
2022-06-09 17:24       ` Reiji Watanabe
2022-06-09 17:24         ` Reiji Watanabe
2022-06-09 17:24         ` Reiji Watanabe
2022-06-10  7:48         ` Marc Zyngier [this message]
2022-06-10  7:48           ` Marc Zyngier
2022-06-10  7:48           ` Marc Zyngier
2022-05-28 11:38 ` [PATCH 07/18] KVM: arm64: Move vcpu configuration flags into their own set Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-06-09  6:15   ` Reiji Watanabe
2022-06-09  6:15     ` Reiji Watanabe
2022-06-09  6:15     ` Reiji Watanabe
2022-05-28 11:38 ` [PATCH 08/18] KVM: arm64: Move vcpu PC/Exception flags to the input flag set Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-06-10  6:13   ` Reiji Watanabe
2022-06-10  6:13     ` Reiji Watanabe
2022-06-10  6:13     ` Reiji Watanabe
2022-05-28 11:38 ` [PATCH 09/18] KVM: arm64: Move vcpu debug/SPE/TRBE " Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-06-08 15:16   ` Fuad Tabba
2022-06-08 15:16     ` Fuad Tabba
2022-06-08 15:16     ` Fuad Tabba
2022-06-08 16:01     ` Marc Zyngier
2022-06-08 16:01       ` Marc Zyngier
2022-06-08 16:01       ` Marc Zyngier
2022-05-28 11:38 ` [PATCH 10/18] KVM: arm64: Move vcpu SVE/SME flags to the state " Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38 ` [PATCH 11/18] KVM: arm64: Move vcpu ON_UNSUPPORTED_CPU flag " Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38 ` [PATCH 12/18] KVM: arm64: Move vcpu WFIT " Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38 ` [PATCH 13/18] KVM: arm64: Kill unused vcpu flags field Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38 ` [PATCH 14/18] KVM: arm64: Convert vcpu sysregs_loaded_on_cpu to a state flag Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38 ` [PATCH 15/18] KVM: arm64: Warn when PENDING_EXCEPTION and INCREMENT_PC are set together Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-06-08 15:16   ` Fuad Tabba
2022-06-08 15:16     ` Fuad Tabba
2022-06-08 15:16     ` Fuad Tabba
2022-06-08 16:42     ` Marc Zyngier
2022-06-08 16:42       ` Marc Zyngier
2022-06-08 16:42       ` Marc Zyngier
2022-05-28 11:38 ` [PATCH 16/18] KVM: arm64: Add build-time sanity checks for flags Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38 ` [PATCH 17/18] KVM: arm64: Reduce the size of the vcpu flag members Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38 ` [PATCH 18/18] KVM: arm64: Document why pause cannot be turned into a flag Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-28 11:38   ` Marc Zyngier
2022-05-30  8:28 ` [PATCH 00/18] KVM/arm64: Refactoring the vcpu flags Marc Zyngier
2022-05-30  8:28   ` Marc Zyngier
2022-05-30  8:28   ` Marc Zyngier
2022-06-07 13:43 ` Marc Zyngier
2022-06-07 13:43   ` Marc Zyngier
2022-06-07 13:43   ` Marc Zyngier

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