From: Peter Maydell <peter.maydell@linaro.org>
To: Andrew Jones <drjones@redhat.com>
Cc: Steven Price <steven.price@arm.com>,
Peter Maydell <Peter.Maydell@arm.com>,
Juan Quintela <quintela@redhat.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Richard Henderson <richard.henderson@linaro.org>,
QEMU Developers <qemu-devel@nongnu.org>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
kvmarm@lists.cs.columbia.edu,
arm-mail-list <linux-arm-kernel@lists.infradead.org>,
Marc Zyngier <maz@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>, Dave Martin <Dave.Martin@arm.com>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 2/2] arm64: kvm: Introduce MTE VCPU feature
Date: Wed, 9 Sep 2020 16:53:02 +0100 [thread overview]
Message-ID: <CAFEAcA_1YnBg3HVmtrSMP8u7GqHY8mtDAJwVcZuNUhwA+q9q=w@mail.gmail.com> (raw)
In-Reply-To: <20200909154804.mide6szbzgdy7jju@kamzik.brq.redhat.com>
On Wed, 9 Sep 2020 at 16:48, Andrew Jones <drjones@redhat.com> wrote:
> We either need a KVM cap or a new CPU feature probing interface to avoid
> making userspace try features one at a time. It's too bad that VCPU_INIT
> doesn't clear all offending features from the feature set when returning
> EINVAL, because then userspace could create a scratch VCPU with everything
> it supports in order to see what KVM also supports in one go.
You could add one if you wanted -- add a new feature bit
TELL_ME_WHAT_YOU_HAVE. If the kernel sees that then on filure
it clears out feature bits it doesn't support and also clears
TELL_ME_WHAT_YOU_HAVE. If QEMU sees EINVAL and TELL_ME_WHAT_YOU_HAVE
is still set, then it knows it's dealing with an old kernel
and has to do one-at-a-time probing. If it sees EINVAL but not
TELL_ME_WHAT_YOU_HAVE then it knows it has a new kernel and
has just got all the info.
-- PMM
WARNING: multiple messages have this Message-ID (diff)
From: Peter Maydell <peter.maydell@linaro.org>
To: Andrew Jones <drjones@redhat.com>
Cc: Peter Maydell <Peter.Maydell@arm.com>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
Juan Quintela <quintela@redhat.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Richard Henderson <richard.henderson@linaro.org>,
QEMU Developers <qemu-devel@nongnu.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@lists.cs.columbia.edu,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH v2 2/2] arm64: kvm: Introduce MTE VCPU feature
Date: Wed, 9 Sep 2020 16:53:02 +0100 [thread overview]
Message-ID: <CAFEAcA_1YnBg3HVmtrSMP8u7GqHY8mtDAJwVcZuNUhwA+q9q=w@mail.gmail.com> (raw)
In-Reply-To: <20200909154804.mide6szbzgdy7jju@kamzik.brq.redhat.com>
On Wed, 9 Sep 2020 at 16:48, Andrew Jones <drjones@redhat.com> wrote:
> We either need a KVM cap or a new CPU feature probing interface to avoid
> making userspace try features one at a time. It's too bad that VCPU_INIT
> doesn't clear all offending features from the feature set when returning
> EINVAL, because then userspace could create a scratch VCPU with everything
> it supports in order to see what KVM also supports in one go.
You could add one if you wanted -- add a new feature bit
TELL_ME_WHAT_YOU_HAVE. If the kernel sees that then on filure
it clears out feature bits it doesn't support and also clears
TELL_ME_WHAT_YOU_HAVE. If QEMU sees EINVAL and TELL_ME_WHAT_YOU_HAVE
is still set, then it knows it's dealing with an old kernel
and has to do one-at-a-time probing. If it sees EINVAL but not
TELL_ME_WHAT_YOU_HAVE then it knows it has a new kernel and
has just got all the info.
-- PMM
WARNING: multiple messages have this Message-ID (diff)
From: Peter Maydell <peter.maydell@linaro.org>
To: Andrew Jones <drjones@redhat.com>
Cc: Peter Maydell <Peter.Maydell@arm.com>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
Juan Quintela <quintela@redhat.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Richard Henderson <richard.henderson@linaro.org>,
QEMU Developers <qemu-devel@nongnu.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@lists.cs.columbia.edu,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH v2 2/2] arm64: kvm: Introduce MTE VCPU feature
Date: Wed, 9 Sep 2020 16:53:02 +0100 [thread overview]
Message-ID: <CAFEAcA_1YnBg3HVmtrSMP8u7GqHY8mtDAJwVcZuNUhwA+q9q=w@mail.gmail.com> (raw)
In-Reply-To: <20200909154804.mide6szbzgdy7jju@kamzik.brq.redhat.com>
On Wed, 9 Sep 2020 at 16:48, Andrew Jones <drjones@redhat.com> wrote:
> We either need a KVM cap or a new CPU feature probing interface to avoid
> making userspace try features one at a time. It's too bad that VCPU_INIT
> doesn't clear all offending features from the feature set when returning
> EINVAL, because then userspace could create a scratch VCPU with everything
> it supports in order to see what KVM also supports in one go.
You could add one if you wanted -- add a new feature bit
TELL_ME_WHAT_YOU_HAVE. If the kernel sees that then on filure
it clears out feature bits it doesn't support and also clears
TELL_ME_WHAT_YOU_HAVE. If QEMU sees EINVAL and TELL_ME_WHAT_YOU_HAVE
is still set, then it knows it's dealing with an old kernel
and has to do one-at-a-time probing. If it sees EINVAL but not
TELL_ME_WHAT_YOU_HAVE then it knows it has a new kernel and
has just got all the info.
-- 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: Andrew Jones <drjones@redhat.com>
Cc: Peter Maydell <Peter.Maydell@arm.com>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
Juan Quintela <quintela@redhat.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Richard Henderson <richard.henderson@linaro.org>,
QEMU Developers <qemu-devel@nongnu.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@lists.cs.columbia.edu,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH v2 2/2] arm64: kvm: Introduce MTE VCPU feature
Date: Wed, 9 Sep 2020 16:53:02 +0100 [thread overview]
Message-ID: <CAFEAcA_1YnBg3HVmtrSMP8u7GqHY8mtDAJwVcZuNUhwA+q9q=w@mail.gmail.com> (raw)
In-Reply-To: <20200909154804.mide6szbzgdy7jju@kamzik.brq.redhat.com>
On Wed, 9 Sep 2020 at 16:48, Andrew Jones <drjones@redhat.com> wrote:
> We either need a KVM cap or a new CPU feature probing interface to avoid
> making userspace try features one at a time. It's too bad that VCPU_INIT
> doesn't clear all offending features from the feature set when returning
> EINVAL, because then userspace could create a scratch VCPU with everything
> it supports in order to see what KVM also supports in one go.
You could add one if you wanted -- add a new feature bit
TELL_ME_WHAT_YOU_HAVE. If the kernel sees that then on filure
it clears out feature bits it doesn't support and also clears
TELL_ME_WHAT_YOU_HAVE. If QEMU sees EINVAL and TELL_ME_WHAT_YOU_HAVE
is still set, then it knows it's dealing with an old kernel
and has to do one-at-a-time probing. If it sees EINVAL but not
TELL_ME_WHAT_YOU_HAVE then it knows it has a new kernel and
has just got all the info.
-- 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:[~2020-09-09 16:55 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 16:00 [PATCH v2 0/2] MTE support for KVM guest Steven Price
2020-09-04 16:00 ` Steven Price
2020-09-04 16:00 ` Steven Price
2020-09-04 16:00 ` Steven Price
2020-09-04 16:00 ` [PATCH v2 1/2] arm64: kvm: Save/restore MTE registers Steven Price
2020-09-04 16:00 ` Steven Price
2020-09-04 16:00 ` Steven Price
2020-09-04 16:00 ` Steven Price
2020-09-04 16:00 ` [PATCH v2 2/2] arm64: kvm: Introduce MTE VCPU feature Steven Price
2020-09-04 16:00 ` Steven Price
2020-09-04 16:00 ` Steven Price
2020-09-04 16:00 ` Steven Price
2020-09-09 15:48 ` Andrew Jones
2020-09-09 15:48 ` Andrew Jones
2020-09-09 15:48 ` Andrew Jones
2020-09-09 15:48 ` Andrew Jones
2020-09-09 15:53 ` Peter Maydell [this message]
2020-09-09 15:53 ` Peter Maydell
2020-09-09 15:53 ` Peter Maydell
2020-09-09 15:53 ` Peter Maydell
2020-09-10 6:38 ` Andrew Jones
2020-09-10 6:38 ` Andrew Jones
2020-09-10 6:38 ` Andrew Jones
2020-09-10 6:38 ` Andrew Jones
2020-09-10 10:01 ` Andrew Jones
2020-09-10 10:01 ` Andrew Jones
2020-09-10 10:01 ` Andrew Jones
2020-09-10 10:01 ` Andrew Jones
2020-09-10 9:21 ` Steven Price
2020-09-10 9:21 ` Steven Price
2020-09-10 9:21 ` Steven Price
2020-09-10 9:21 ` Steven Price
2020-09-10 11:49 ` Andrew Jones
2020-09-10 11:49 ` Andrew Jones
2020-09-10 11:49 ` Andrew Jones
2020-09-10 11:49 ` Andrew Jones
2020-09-07 15:28 ` [PATCH v2 0/2] MTE support for KVM guest Dr. David Alan Gilbert
2020-09-07 15:28 ` Dr. David Alan Gilbert
2020-09-07 15:28 ` Dr. David Alan Gilbert
2020-09-07 15:28 ` Dr. David Alan Gilbert
2020-09-09 9:15 ` Steven Price
2020-09-09 9:15 ` Steven Price
2020-09-09 9:15 ` Steven Price
2020-09-09 9:15 ` Steven Price
2020-09-09 15:25 ` Andrew Jones
2020-09-09 15:25 ` Andrew Jones
2020-09-09 15:25 ` Andrew Jones
2020-09-09 15:25 ` Andrew Jones
2020-09-09 16:04 ` Steven Price
2020-09-09 16:04 ` Steven Price
2020-09-09 16:04 ` Steven Price
2020-09-09 16:04 ` Steven Price
2020-09-10 6:29 ` Andrew Jones
2020-09-10 6:29 ` Andrew Jones
2020-09-10 6:29 ` Andrew Jones
2020-09-10 6:29 ` Andrew Jones
2020-09-10 9:21 ` Steven Price
2020-09-10 9:21 ` Steven Price
2020-09-10 9:21 ` Steven Price
2020-09-10 9:21 ` Steven Price
2020-09-10 13:56 ` Andrew Jones
2020-09-10 13:56 ` Andrew Jones
2020-09-10 13:56 ` Andrew Jones
2020-09-10 13:56 ` Andrew Jones
2020-09-10 14:14 ` Steven Price
2020-09-10 14:14 ` Steven Price
2020-09-10 14:14 ` Steven Price
2020-09-10 14:14 ` Steven Price
2020-09-10 1:45 ` Richard Henderson
2020-09-10 1:45 ` Richard Henderson
2020-09-10 1:45 ` Richard Henderson
2020-09-10 1:45 ` Richard Henderson
2020-09-10 5:44 ` Andrew Jones
2020-09-10 5:44 ` Andrew Jones
2020-09-10 5:44 ` Andrew Jones
2020-09-10 5:44 ` Andrew Jones
2020-09-10 13:27 ` Dr. David Alan Gilbert
2020-09-10 13:27 ` Dr. David Alan Gilbert
2020-09-10 13:27 ` Dr. David Alan Gilbert
2020-09-10 13:27 ` Dr. David Alan Gilbert
2020-09-10 13:39 ` Andrew Jones
2020-09-10 13:39 ` Andrew Jones
2020-09-10 13:39 ` Andrew Jones
2020-09-10 13:39 ` Andrew Jones
2020-09-10 0:33 ` Richard Henderson
2020-09-10 0:33 ` Richard Henderson
2020-09-10 0:33 ` Richard Henderson
2020-09-10 0:33 ` Richard Henderson
2020-09-10 10:24 ` Steven Price
2020-09-10 10:24 ` Steven Price
2020-09-10 10:24 ` Steven Price
2020-09-10 10:24 ` Steven Price
2020-09-10 15:36 ` Richard Henderson
2020-09-10 15:36 ` Richard Henderson
2020-09-10 15:36 ` Richard Henderson
2020-09-10 15:36 ` Richard Henderson
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