From: Peter Maydell <peter.maydell@linaro.org>
To: Steven Price <steven.price@arm.com>
Cc: Haibo Xu <haibo.xu@linaro.org>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
Juan Quintela <quintela@redhat.com>,
Marc Zyngier <maz@kernel.org>,
Richard Henderson <richard.henderson@linaro.org>,
QEMU Developers <qemu-devel@nongnu.org>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>,
kvmarm <kvmarm@lists.cs.columbia.edu>,
arm-mail-list <linux-arm-kernel@lists.infradead.org>,
Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH v5 0/2] MTE support for KVM guest
Date: Mon, 7 Dec 2020 15:27:40 +0000 [thread overview]
Message-ID: <CAFEAcA_Q8RSB-zcS8+cEfvWz_0U5GLzmsf12m_7BFjX8h-1hrA@mail.gmail.com> (raw)
In-Reply-To: <46fd98a2-ee39-0086-9159-b38c406935ab@arm.com>
On Mon, 7 Dec 2020 at 14:48, Steven Price <steven.price@arm.com> wrote:
> Sounds like you are making good progress - thanks for the update. Have
> you thought about how the PROT_MTE mappings might work if QEMU itself
> were to use MTE? My worry is that we end up with MTE in a guest
> preventing QEMU from using MTE itself (because of the PROT_MTE
> mappings). I'm hoping QEMU can wrap its use of guest memory in a
> sequence which disables tag checking (something similar will be needed
> for the "protected VM" use case anyway), but this isn't something I've
> looked into.
It's not entirely the same as the "protected VM" case. For that
the patches currently on list basically special case "this is a
debug access (eg from gdbstub/monitor)" which then either gets
to go via "decrypt guest RAM for debug" or gets failed depending
on whether the VM has a debug-is-ok flag enabled. For an MTE
guest the common case will be guests doing standard DMA operations
to or from guest memory. The ideal API for that from QEMU's
point of view would be "accesses to guest RAM don't do tag
checks, even if tag checks are enabled for accesses QEMU does to
memory it has allocated itself as a normal userspace program".
thanks
-- PMM
WARNING: multiple messages have this Message-ID (diff)
From: Peter Maydell <peter.maydell@linaro.org>
To: Steven Price <steven.price@arm.com>
Cc: Juan Quintela <quintela@redhat.com>,
Marc Zyngier <maz@kernel.org>,
Richard Henderson <richard.henderson@linaro.org>,
QEMU Developers <qemu-devel@nongnu.org>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
arm-mail-list <linux-arm-kernel@lists.infradead.org>,
Haibo Xu <haibo.xu@linaro.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>,
kvmarm <kvmarm@lists.cs.columbia.edu>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH v5 0/2] MTE support for KVM guest
Date: Mon, 7 Dec 2020 15:27:40 +0000 [thread overview]
Message-ID: <CAFEAcA_Q8RSB-zcS8+cEfvWz_0U5GLzmsf12m_7BFjX8h-1hrA@mail.gmail.com> (raw)
In-Reply-To: <46fd98a2-ee39-0086-9159-b38c406935ab@arm.com>
On Mon, 7 Dec 2020 at 14:48, Steven Price <steven.price@arm.com> wrote:
> Sounds like you are making good progress - thanks for the update. Have
> you thought about how the PROT_MTE mappings might work if QEMU itself
> were to use MTE? My worry is that we end up with MTE in a guest
> preventing QEMU from using MTE itself (because of the PROT_MTE
> mappings). I'm hoping QEMU can wrap its use of guest memory in a
> sequence which disables tag checking (something similar will be needed
> for the "protected VM" use case anyway), but this isn't something I've
> looked into.
It's not entirely the same as the "protected VM" case. For that
the patches currently on list basically special case "this is a
debug access (eg from gdbstub/monitor)" which then either gets
to go via "decrypt guest RAM for debug" or gets failed depending
on whether the VM has a debug-is-ok flag enabled. For an MTE
guest the common case will be guests doing standard DMA operations
to or from guest memory. The ideal API for that from QEMU's
point of view would be "accesses to guest RAM don't do tag
checks, even if tag checks are enabled for accesses QEMU does to
memory it has allocated itself as a normal userspace program".
thanks
-- PMM
WARNING: multiple messages have this Message-ID (diff)
From: Peter Maydell <peter.maydell@linaro.org>
To: Steven Price <steven.price@arm.com>
Cc: Juan Quintela <quintela@redhat.com>,
Marc Zyngier <maz@kernel.org>,
Richard Henderson <richard.henderson@linaro.org>,
QEMU Developers <qemu-devel@nongnu.org>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
arm-mail-list <linux-arm-kernel@lists.infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>,
kvmarm <kvmarm@lists.cs.columbia.edu>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH v5 0/2] MTE support for KVM guest
Date: Mon, 7 Dec 2020 15:27:40 +0000 [thread overview]
Message-ID: <CAFEAcA_Q8RSB-zcS8+cEfvWz_0U5GLzmsf12m_7BFjX8h-1hrA@mail.gmail.com> (raw)
In-Reply-To: <46fd98a2-ee39-0086-9159-b38c406935ab@arm.com>
On Mon, 7 Dec 2020 at 14:48, Steven Price <steven.price@arm.com> wrote:
> Sounds like you are making good progress - thanks for the update. Have
> you thought about how the PROT_MTE mappings might work if QEMU itself
> were to use MTE? My worry is that we end up with MTE in a guest
> preventing QEMU from using MTE itself (because of the PROT_MTE
> mappings). I'm hoping QEMU can wrap its use of guest memory in a
> sequence which disables tag checking (something similar will be needed
> for the "protected VM" use case anyway), but this isn't something I've
> looked into.
It's not entirely the same as the "protected VM" case. For that
the patches currently on list basically special case "this is a
debug access (eg from gdbstub/monitor)" which then either gets
to go via "decrypt guest RAM for debug" or gets failed depending
on whether the VM has a debug-is-ok flag enabled. For an MTE
guest the common case will be guests doing standard DMA operations
to or from guest memory. The ideal API for that from QEMU's
point of view would be "accesses to guest RAM don't do tag
checks, even if tag checks are enabled for accesses QEMU does to
memory it has allocated itself as a normal userspace program".
thanks
-- PMM
_______________________________________________
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: Peter Maydell <peter.maydell@linaro.org>
To: Steven Price <steven.price@arm.com>
Cc: Juan Quintela <quintela@redhat.com>,
Marc Zyngier <maz@kernel.org>,
Richard Henderson <richard.henderson@linaro.org>,
QEMU Developers <qemu-devel@nongnu.org>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
arm-mail-list <linux-arm-kernel@lists.infradead.org>,
Haibo Xu <haibo.xu@linaro.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>,
kvmarm <kvmarm@lists.cs.columbia.edu>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH v5 0/2] MTE support for KVM guest
Date: Mon, 7 Dec 2020 15:27:40 +0000 [thread overview]
Message-ID: <CAFEAcA_Q8RSB-zcS8+cEfvWz_0U5GLzmsf12m_7BFjX8h-1hrA@mail.gmail.com> (raw)
In-Reply-To: <46fd98a2-ee39-0086-9159-b38c406935ab@arm.com>
On Mon, 7 Dec 2020 at 14:48, Steven Price <steven.price@arm.com> wrote:
> Sounds like you are making good progress - thanks for the update. Have
> you thought about how the PROT_MTE mappings might work if QEMU itself
> were to use MTE? My worry is that we end up with MTE in a guest
> preventing QEMU from using MTE itself (because of the PROT_MTE
> mappings). I'm hoping QEMU can wrap its use of guest memory in a
> sequence which disables tag checking (something similar will be needed
> for the "protected VM" use case anyway), but this isn't something I've
> looked into.
It's not entirely the same as the "protected VM" case. For that
the patches currently on list basically special case "this is a
debug access (eg from gdbstub/monitor)" which then either gets
to go via "decrypt guest RAM for debug" or gets failed depending
on whether the VM has a debug-is-ok flag enabled. For an MTE
guest the common case will be guests doing standard DMA operations
to or from guest memory. The ideal API for that from QEMU's
point of view would be "accesses to guest RAM don't do tag
checks, even if tag checks are enabled for accesses QEMU does to
memory it has allocated itself as a normal userspace program".
thanks
-- PMM
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-12-07 15:28 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 [this message]
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
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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