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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Steven Price <steven.price@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>,
	James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	kvmarm <kvmarm@lists.cs.columbia.edu>,
	arm-mail-list <linux-arm-kernel@lists.infradead.org>,
	lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Dave Martin <Dave.Martin@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	QEMU Developers <qemu-devel@nongnu.org>,
	Juan Quintela <quintela@redhat.com>,
	Richard Henderson <richard.henderson@linaro.org>,
	Haibo Xu <Haibo.Xu@arm.com>, Andrew Jones <drjones@redhat.com>
Subject: Re: [PATCH v5 0/2] MTE support for KVM guest
Date: Mon, 23 Nov 2020 12:16:11 +0000	[thread overview]
Message-ID: <20201123121611.GG3022@work-vm> (raw)
In-Reply-To: <CAFEAcA85fiqA206FuFANKbV_3GkfY1F8Gv7MP58BgTT81bs9kA@mail.gmail.com>

* Peter Maydell (peter.maydell@linaro.org) wrote:
> On Thu, 19 Nov 2020 at 15:39, Steven Price <steven.price@arm.com> wrote:
> > This series adds support for Arm's Memory Tagging Extension (MTE) to
> > KVM, allowing KVM guests to make use of it. This builds on the existing
> > user space support already in v5.10-rc1, see [1] for an overview.
> 
> > The change to require the VMM to map all guest memory PROT_MTE is
> > significant as it means that the VMM has to deal with the MTE tags even
> > if it doesn't care about them (e.g. for virtual devices or if the VMM
> > doesn't support migration). Also unfortunately because the VMM can
> > change the memory layout at any time the check for PROT_MTE/VM_MTE has
> > to be done very late (at the point of faulting pages into stage 2).
> 
> I'm a bit dubious about requring the VMM to map the guest memory
> PROT_MTE unless somebody's done at least a sketch of the design
> for how this would work on the QEMU side. Currently QEMU just
> assumes the guest memory is guest memory and it can access it
> without special precautions...

Although that is also changing because of the encrypted/protected memory
in things like SEV.

Dave

> thanks
> -- PMM
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK


WARNING: multiple messages have this Message-ID (diff)
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Andrew Jones <drjones@redhat.com>, Haibo Xu <Haibo.Xu@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	QEMU Developers <qemu-devel@nongnu.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Juan Quintela <quintela@redhat.com>,
	Richard Henderson <richard.henderson@linaro.org>,
	lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Steven Price <steven.price@arm.com>,
	James Morse <james.morse@arm.com>,
	arm-mail-list <linux-arm-kernel@lists.infradead.org>,
	Marc Zyngier <maz@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Will Deacon <will@kernel.org>,
	kvmarm <kvmarm@lists.cs.columbia.edu>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH v5 0/2] MTE support for KVM guest
Date: Mon, 23 Nov 2020 12:16:11 +0000	[thread overview]
Message-ID: <20201123121611.GG3022@work-vm> (raw)
In-Reply-To: <CAFEAcA85fiqA206FuFANKbV_3GkfY1F8Gv7MP58BgTT81bs9kA@mail.gmail.com>

* Peter Maydell (peter.maydell@linaro.org) wrote:
> On Thu, 19 Nov 2020 at 15:39, Steven Price <steven.price@arm.com> wrote:
> > This series adds support for Arm's Memory Tagging Extension (MTE) to
> > KVM, allowing KVM guests to make use of it. This builds on the existing
> > user space support already in v5.10-rc1, see [1] for an overview.
> 
> > The change to require the VMM to map all guest memory PROT_MTE is
> > significant as it means that the VMM has to deal with the MTE tags even
> > if it doesn't care about them (e.g. for virtual devices or if the VMM
> > doesn't support migration). Also unfortunately because the VMM can
> > change the memory layout at any time the check for PROT_MTE/VM_MTE has
> > to be done very late (at the point of faulting pages into stage 2).
> 
> I'm a bit dubious about requring the VMM to map the guest memory
> PROT_MTE unless somebody's done at least a sketch of the design
> for how this would work on the QEMU side. Currently QEMU just
> assumes the guest memory is guest memory and it can access it
> without special precautions...

Although that is also changing because of the encrypted/protected memory
in things like SEV.

Dave

> thanks
> -- PMM
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK



WARNING: multiple messages have this Message-ID (diff)
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: QEMU Developers <qemu-devel@nongnu.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Juan Quintela <quintela@redhat.com>,
	Richard Henderson <richard.henderson@linaro.org>,
	lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Steven Price <steven.price@arm.com>,
	arm-mail-list <linux-arm-kernel@lists.infradead.org>,
	Marc Zyngier <maz@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Will Deacon <will@kernel.org>,
	kvmarm <kvmarm@lists.cs.columbia.edu>,
	Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH v5 0/2] MTE support for KVM guest
Date: Mon, 23 Nov 2020 12:16:11 +0000	[thread overview]
Message-ID: <20201123121611.GG3022@work-vm> (raw)
In-Reply-To: <CAFEAcA85fiqA206FuFANKbV_3GkfY1F8Gv7MP58BgTT81bs9kA@mail.gmail.com>

* Peter Maydell (peter.maydell@linaro.org) wrote:
> On Thu, 19 Nov 2020 at 15:39, Steven Price <steven.price@arm.com> wrote:
> > This series adds support for Arm's Memory Tagging Extension (MTE) to
> > KVM, allowing KVM guests to make use of it. This builds on the existing
> > user space support already in v5.10-rc1, see [1] for an overview.
> 
> > The change to require the VMM to map all guest memory PROT_MTE is
> > significant as it means that the VMM has to deal with the MTE tags even
> > if it doesn't care about them (e.g. for virtual devices or if the VMM
> > doesn't support migration). Also unfortunately because the VMM can
> > change the memory layout at any time the check for PROT_MTE/VM_MTE has
> > to be done very late (at the point of faulting pages into stage 2).
> 
> I'm a bit dubious about requring the VMM to map the guest memory
> PROT_MTE unless somebody's done at least a sketch of the design
> for how this would work on the QEMU side. Currently QEMU just
> assumes the guest memory is guest memory and it can access it
> without special precautions...

Although that is also changing because of the encrypted/protected memory
in things like SEV.

Dave

> thanks
> -- PMM
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

_______________________________________________
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: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Andrew Jones <drjones@redhat.com>, Haibo Xu <Haibo.Xu@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	QEMU Developers <qemu-devel@nongnu.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Juan Quintela <quintela@redhat.com>,
	Richard Henderson <richard.henderson@linaro.org>,
	lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Steven Price <steven.price@arm.com>,
	James Morse <james.morse@arm.com>,
	arm-mail-list <linux-arm-kernel@lists.infradead.org>,
	Marc Zyngier <maz@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Will Deacon <will@kernel.org>,
	kvmarm <kvmarm@lists.cs.columbia.edu>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH v5 0/2] MTE support for KVM guest
Date: Mon, 23 Nov 2020 12:16:11 +0000	[thread overview]
Message-ID: <20201123121611.GG3022@work-vm> (raw)
In-Reply-To: <CAFEAcA85fiqA206FuFANKbV_3GkfY1F8Gv7MP58BgTT81bs9kA@mail.gmail.com>

* Peter Maydell (peter.maydell@linaro.org) wrote:
> On Thu, 19 Nov 2020 at 15:39, Steven Price <steven.price@arm.com> wrote:
> > This series adds support for Arm's Memory Tagging Extension (MTE) to
> > KVM, allowing KVM guests to make use of it. This builds on the existing
> > user space support already in v5.10-rc1, see [1] for an overview.
> 
> > The change to require the VMM to map all guest memory PROT_MTE is
> > significant as it means that the VMM has to deal with the MTE tags even
> > if it doesn't care about them (e.g. for virtual devices or if the VMM
> > doesn't support migration). Also unfortunately because the VMM can
> > change the memory layout at any time the check for PROT_MTE/VM_MTE has
> > to be done very late (at the point of faulting pages into stage 2).
> 
> I'm a bit dubious about requring the VMM to map the guest memory
> PROT_MTE unless somebody's done at least a sketch of the design
> for how this would work on the QEMU side. Currently QEMU just
> assumes the guest memory is guest memory and it can access it
> without special precautions...

Although that is also changing because of the encrypted/protected memory
in things like SEV.

Dave

> thanks
> -- PMM
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK


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

  parent reply	other threads:[~2020-11-23 12:17 UTC|newest]

Thread overview: 152+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-19 15:38 [PATCH v5 0/2] MTE support for KVM guest Steven Price
2020-11-19 15:38 ` Steven Price
2020-11-19 15:38 ` Steven Price
2020-11-19 15:38 ` Steven Price
2020-11-19 15:39 ` [PATCH v5 1/2] arm64: kvm: Save/restore MTE registers Steven Price
2020-11-19 15:39   ` Steven Price
2020-11-19 15:39   ` Steven Price
2020-11-19 15:39   ` Steven Price
2020-11-19 15:39 ` [PATCH v5 2/2] arm64: kvm: Introduce MTE VCPU feature Steven Price
2020-11-19 15:39   ` Steven Price
2020-11-19 15:39   ` Steven Price
2020-11-19 15:39   ` Steven Price
2020-11-19 15:45 ` [PATCH v5 0/2] MTE support for KVM guest Peter Maydell
2020-11-19 15:45   ` Peter Maydell
2020-11-19 15:45   ` Peter Maydell
2020-11-19 15:45   ` Peter Maydell
2020-11-19 15:57   ` Steven Price
2020-11-19 15:57     ` Steven Price
2020-11-19 15:57     ` Steven Price
2020-11-19 15:57     ` Steven Price
2020-11-19 16:39     ` Peter Maydell
2020-11-19 16:39       ` Peter Maydell
2020-11-19 16:39       ` Peter Maydell
2020-11-19 16:39       ` Peter Maydell
2020-11-19 18:42   ` Andrew Jones
2020-11-19 18:42     ` Andrew Jones
2020-11-19 18:42     ` Andrew Jones
2020-11-19 18:42     ` Andrew Jones
2020-11-19 19:11     ` Marc Zyngier
2020-11-19 19:11       ` Marc Zyngier
2020-11-19 19:11       ` Marc Zyngier
2020-11-19 19:11       ` Marc Zyngier
2020-11-20  9:50       ` Steven Price
2020-11-20  9:50         ` Steven Price
2020-11-20  9:50         ` Steven Price
2020-11-20  9:50         ` Steven Price
2020-11-20  9:56         ` Marc Zyngier
2020-11-20  9:56           ` Marc Zyngier
2020-11-20  9:56           ` Marc Zyngier
2020-11-20  9:56           ` Marc Zyngier
2020-11-20  9:58           ` Steven Price
2020-11-20  9:58             ` Steven Price
2020-11-20  9:58             ` Steven Price
2020-11-20  9:58             ` Steven Price
2020-12-04  8:25         ` Haibo Xu
2020-12-04  8:25           ` Haibo Xu
2020-12-04  8:25           ` Haibo Xu
2020-12-04  8:25           ` Haibo Xu
2020-12-07 14:48           ` Steven Price
2020-12-07 14:48             ` Steven Price
2020-12-07 14:48             ` Steven Price
2020-12-07 14:48             ` Steven Price
2020-12-07 15:27             ` Peter Maydell
2020-12-07 15:27               ` Peter Maydell
2020-12-07 15:27               ` Peter Maydell
2020-12-07 15:27               ` Peter Maydell
2020-12-07 15:45               ` Steven Price
2020-12-07 15:45                 ` Steven Price
2020-12-07 15:45                 ` Steven Price
2020-12-07 15:45                 ` Steven Price
2020-12-07 16:05                 ` Marc Zyngier
2020-12-07 16:05                   ` Marc Zyngier
2020-12-07 16:05                   ` Marc Zyngier
2020-12-07 16:05                   ` Marc Zyngier
2020-12-07 16:34                   ` Catalin Marinas
2020-12-07 16:34                     ` Catalin Marinas
2020-12-07 16:34                     ` Catalin Marinas
2020-12-07 16:34                     ` Catalin Marinas
2020-12-07 19:03                     ` Marc Zyngier
2020-12-07 19:03                       ` Marc Zyngier
2020-12-07 19:03                       ` Marc Zyngier
2020-12-07 19:03                       ` Marc Zyngier
2020-12-08 17:21                       ` Catalin Marinas
2020-12-08 17:21                         ` Catalin Marinas
2020-12-08 17:21                         ` Catalin Marinas
2020-12-08 17:21                         ` Catalin Marinas
2020-12-08 18:21                         ` Marc Zyngier
2020-12-08 18:21                           ` Marc Zyngier
2020-12-08 18:21                           ` Marc Zyngier
2020-12-08 18:21                           ` Marc Zyngier
2020-12-09 12:44                           ` Catalin Marinas
2020-12-09 12:44                             ` Catalin Marinas
2020-12-09 12:44                             ` Catalin Marinas
2020-12-09 12:44                             ` Catalin Marinas
2020-12-09 13:25                             ` Marc Zyngier
2020-12-09 13:25                               ` Marc Zyngier
2020-12-09 13:25                               ` Marc Zyngier
2020-12-09 13:25                               ` Marc Zyngier
2020-12-09 15:27                               ` Catalin Marinas
2020-12-09 15:27                                 ` Catalin Marinas
2020-12-09 15:27                                 ` Catalin Marinas
2020-12-09 15:27                                 ` Catalin Marinas
2020-12-09 18:27                                 ` Richard Henderson
2020-12-09 18:27                                   ` Richard Henderson
2020-12-09 18:27                                   ` Richard Henderson
2020-12-09 18:27                                   ` Richard Henderson
2020-12-09 18:39                                   ` Catalin Marinas
2020-12-09 18:39                                     ` Catalin Marinas
2020-12-09 18:39                                     ` Catalin Marinas
2020-12-09 18:39                                     ` Catalin Marinas
2020-12-09 20:13                                     ` Richard Henderson
2020-12-09 20:13                                       ` Richard Henderson
2020-12-09 20:13                                       ` Richard Henderson
2020-12-09 20:13                                       ` Richard Henderson
2020-12-09 20:20                                       ` Peter Maydell
2020-12-09 20:20                                         ` Peter Maydell
2020-12-09 20:20                                         ` Peter Maydell
2020-12-09 20:20                                         ` Peter Maydell
2020-12-07 16:44                 ` Dr. David Alan Gilbert
2020-12-07 16:44                   ` Dr. David Alan Gilbert
2020-12-07 16:44                   ` Dr. David Alan Gilbert
2020-12-07 16:44                   ` Dr. David Alan Gilbert
2020-12-07 17:10                   ` Peter Maydell
2020-12-07 17:10                     ` Peter Maydell
2020-12-07 17:10                     ` Peter Maydell
2020-12-07 17:10                     ` Peter Maydell
2020-12-07 17:44                     ` Dr. David Alan Gilbert
2020-12-07 17:44                       ` Dr. David Alan Gilbert
2020-12-07 17:44                       ` Dr. David Alan Gilbert
2020-12-07 17:44                       ` Dr. David Alan Gilbert
2020-12-08 10:05                   ` Haibo Xu
2020-12-08 10:05                     ` Haibo Xu
2020-12-08 10:05                     ` Haibo Xu
2020-12-08 10:05                     ` Haibo Xu
2020-12-08  9:51             ` Haibo Xu
2020-12-08  9:51               ` Haibo Xu
2020-12-08  9:51               ` Haibo Xu
2020-12-08  9:51               ` Haibo Xu
2020-12-08 10:01               ` Marc Zyngier
2020-12-08 10:01                 ` Marc Zyngier
2020-12-08 10:01                 ` Marc Zyngier
2020-12-08 10:01                 ` Marc Zyngier
2020-12-08 10:10                 ` Haibo Xu
2020-12-08 10:10                   ` Haibo Xu
2020-12-08 10:10                   ` Haibo Xu
2020-12-08 10:10                   ` Haibo Xu
2020-12-16  7:31             ` Haibo Xu
2020-12-16  7:31               ` Haibo Xu
2020-12-16  7:31               ` Haibo Xu
2020-12-16  7:31               ` Haibo Xu
2020-12-16 10:22               ` Steven Price
2020-12-16 10:22                 ` Steven Price
2020-12-16 10:22                 ` Steven Price
2020-12-16 10:22                 ` Steven Price
2020-12-17  1:47                 ` Haibo Xu
2020-12-17  1:47                   ` Haibo Xu
2020-12-17  1:47                   ` Haibo Xu
2020-12-17  1:47                   ` Haibo Xu
2020-11-23 12:16   ` Dr. David Alan Gilbert [this message]
2020-11-23 12:16     ` Dr. David Alan Gilbert
2020-11-23 12:16     ` Dr. David Alan Gilbert
2020-11-23 12:16     ` Dr. David Alan Gilbert

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