From: James Morse <james.morse@arm.com>
To: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: maz@kernel.org, linux-arm-kernel@lists.infradead.org,
will@kernel.org, kvmarm@lists.cs.columbia.edu
Subject: Re: [RFC PATCH v3 06/16] KVM: arm64: Introduce SPE primitives
Date: Thu, 19 Nov 2020 16:58:26 +0000 [thread overview]
Message-ID: <8939725c-0922-e147-2622-ae5f752a74fc@arm.com> (raw)
In-Reply-To: <20201027172705.15181-7-alexandru.elisei@arm.com>
Hi Alex,
On 27/10/2020 17:26, Alexandru Elisei wrote:
> KVM SPE emulation depends on the configuration option KVM_ARM_SPE and on on
> having hardware SPE support on all CPUs.
> The host driver must be
> compiled-in because we need the SPE interrupt to be enabled; it will be
> used to kick us out of the guest when the profiling buffer management
> interrupt is asserted by the GIC (for example, when the buffer is full).
Great: SPE IRQ very important...
> Add a VCPU flag to inform KVM that the guest has SPE enabled.
>
> It's worth noting that even though the KVM_ARM_SPE config option is gated
> by the SPE host driver being compiled-in, we don't actually check that the
> driver was loaded successfully when we advertise SPE support for guests.
Eh?
> That's because we can live with the SPE interrupt being disabled. There is
> a delay between when the SPE hardware asserts the interrupt and when the
> GIC samples the interrupt line and asserts it to the CPU. If the SPE
> interrupt is disabled at the GIC level, this delay will be larger,
How does this work? Surely the IRQ needs to be enabled before it can become pending at the
CPU to kick us out of the guest...
> at most a host timer tick.
(Because the timer brings us out of the guest anyway?)
Thanks,
James
_______________________________________________
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: James Morse <james.morse@arm.com>
To: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: suzuki.poulose@arm.com, maz@kernel.org,
linux-arm-kernel@lists.infradead.org, will@kernel.org,
kvmarm@lists.cs.columbia.edu, julien.thierry.kdev@gmail.com
Subject: Re: [RFC PATCH v3 06/16] KVM: arm64: Introduce SPE primitives
Date: Thu, 19 Nov 2020 16:58:26 +0000 [thread overview]
Message-ID: <8939725c-0922-e147-2622-ae5f752a74fc@arm.com> (raw)
In-Reply-To: <20201027172705.15181-7-alexandru.elisei@arm.com>
Hi Alex,
On 27/10/2020 17:26, Alexandru Elisei wrote:
> KVM SPE emulation depends on the configuration option KVM_ARM_SPE and on on
> having hardware SPE support on all CPUs.
> The host driver must be
> compiled-in because we need the SPE interrupt to be enabled; it will be
> used to kick us out of the guest when the profiling buffer management
> interrupt is asserted by the GIC (for example, when the buffer is full).
Great: SPE IRQ very important...
> Add a VCPU flag to inform KVM that the guest has SPE enabled.
>
> It's worth noting that even though the KVM_ARM_SPE config option is gated
> by the SPE host driver being compiled-in, we don't actually check that the
> driver was loaded successfully when we advertise SPE support for guests.
Eh?
> That's because we can live with the SPE interrupt being disabled. There is
> a delay between when the SPE hardware asserts the interrupt and when the
> GIC samples the interrupt line and asserts it to the CPU. If the SPE
> interrupt is disabled at the GIC level, this delay will be larger,
How does this work? Surely the IRQ needs to be enabled before it can become pending at the
CPU to kick us out of the guest...
> at most a host timer tick.
(Because the timer brings us out of the guest anyway?)
Thanks,
James
_______________________________________________
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:[~2020-11-19 16:58 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 17:26 [RFC PATCH v3 00/16] KVM: arm64: Add Statistical Profiling Extension (SPE) support Alexandru Elisei
2020-10-27 17:26 ` Alexandru Elisei
2020-10-27 17:26 ` [RFC PATCH v3 01/16] KVM: arm64: Initialize VCPU mdcr_el2 before loading it Alexandru Elisei
2020-10-27 17:26 ` Alexandru Elisei
2020-11-19 16:58 ` James Morse
2020-11-19 16:58 ` James Morse
2020-12-02 14:25 ` Alexandru Elisei
2020-12-02 14:25 ` Alexandru Elisei
2020-10-27 17:26 ` [RFC PATCH v3 02/16] dt-bindings: ARM SPE: Highlight the need for PPI partitions on heterogeneous systems Alexandru Elisei
2020-10-27 17:26 ` Alexandru Elisei
2020-10-27 17:26 ` [RFC PATCH v3 03/16] KVM: arm64: Hide SPE from guests Alexandru Elisei
2020-10-27 17:26 ` Alexandru Elisei
2020-10-27 17:26 ` [RFC PATCH v3 04/16] arm64: Introduce CPU SPE feature Alexandru Elisei
2020-10-27 17:26 ` Alexandru Elisei
2020-11-19 16:58 ` James Morse
2020-11-19 16:58 ` James Morse
2020-12-02 14:29 ` Alexandru Elisei
2020-12-02 14:29 ` Alexandru Elisei
2020-12-02 17:23 ` Will Deacon
2020-12-02 17:23 ` Will Deacon
2020-12-03 10:07 ` Alexandru Elisei
2020-12-03 10:07 ` Alexandru Elisei
2020-10-27 17:26 ` [RFC PATCH v3 05/16] KVM: arm64: Introduce VCPU " Alexandru Elisei
2020-10-27 17:26 ` Alexandru Elisei
2020-10-27 17:26 ` [RFC PATCH v3 06/16] KVM: arm64: Introduce SPE primitives Alexandru Elisei
2020-10-27 17:26 ` Alexandru Elisei
2020-11-19 16:58 ` James Morse [this message]
2020-11-19 16:58 ` James Morse
2020-12-02 15:13 ` Alexandru Elisei
2020-12-02 15:13 ` Alexandru Elisei
2020-10-27 17:26 ` [RFC PATCH v3 07/16] KVM: arm64: Define SPE data structure for each VCPU Alexandru Elisei
2020-10-27 17:26 ` Alexandru Elisei
2020-10-27 17:26 ` [RFC PATCH v3 08/16] KVM: arm64: Add a new VCPU device control group for SPE Alexandru Elisei
2020-10-27 17:26 ` Alexandru Elisei
2020-11-05 9:58 ` Haibo Xu
2020-11-05 9:58 ` Haibo Xu
2020-12-02 15:20 ` Alexandru Elisei
2020-12-02 15:20 ` Alexandru Elisei
2020-11-19 16:58 ` James Morse
2020-11-19 16:58 ` James Morse
2020-12-02 16:28 ` Alexandru Elisei
2020-12-02 16:28 ` Alexandru Elisei
2020-10-27 17:26 ` [RFC PATCH v3 09/16] KVM: arm64: Use separate function for the mapping size in user_mem_abort() Alexandru Elisei
2020-10-27 17:26 ` Alexandru Elisei
2020-11-05 10:01 ` Haibo Xu
2020-11-05 10:01 ` Haibo Xu
2020-12-02 16:29 ` Alexandru Elisei
2020-12-02 16:29 ` Alexandru Elisei
2020-10-27 17:26 ` [RFC PATCH v3 10/16] KVM: arm64: Add a new VM device control group for SPE Alexandru Elisei
2020-10-27 17:26 ` Alexandru Elisei
2020-11-05 10:10 ` Haibo Xu
2020-11-05 10:10 ` Haibo Xu
2020-12-02 16:35 ` Alexandru Elisei
2020-12-02 16:35 ` Alexandru Elisei
2020-11-19 16:59 ` James Morse
2020-11-19 16:59 ` James Morse
2021-03-23 14:27 ` Alexandru Elisei
2021-03-23 14:27 ` Alexandru Elisei
2020-10-27 17:27 ` [RFC PATCH v3 11/16] KVM: arm64: Add SPE system registers to VCPU context Alexandru Elisei
2020-10-27 17:27 ` Alexandru Elisei
2020-10-27 17:27 ` [RFC PATCH v3 12/16] KVM: arm64: VHE: Clear MDCR_EL2.E2PB in vcpu_put() Alexandru Elisei
2020-10-27 17:27 ` Alexandru Elisei
2020-10-27 17:27 ` [RFC PATCH v3 13/16] KVM: arm64: Switch SPE context on VM entry/exit Alexandru Elisei
2020-10-27 17:27 ` Alexandru Elisei
2020-10-27 17:27 ` [RFC PATCH v3 14/16] KVM: arm64: Emulate SPE buffer management interrupt Alexandru Elisei
2020-10-27 17:27 ` Alexandru Elisei
2020-10-27 17:27 ` [RFC PATCH v3 15/16] KVM: arm64: Enable SPE for guests Alexandru Elisei
2020-10-27 17:27 ` Alexandru Elisei
2020-10-27 17:27 ` [RFC PATCH v3 16/16] Documentation: arm64: Document ARM Neoverse-N1 erratum #1688567 Alexandru Elisei
2020-10-27 17:27 ` Alexandru Elisei
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