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From: Marc Zyngier <maz@kernel.org>
To: Oliver Upton <oliver.upton@linux.dev>
Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Raghavendra Rao Ananta <rananta@google.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Will Deacon <will@kernel.org>, James Clark <james.clark@arm.com>
Subject: Re: [PATCH 1/2] KVM: arm64: Disallow vPMU for NV guests
Date: Wed, 11 Oct 2023 16:54:49 +0100	[thread overview]
Message-ID: <281b88c0d74b9260b659e6be579a4984@kernel.org> (raw)
In-Reply-To: <20231011081649.3226792-2-oliver.upton@linux.dev>

On 2023-10-11 09:16, Oliver Upton wrote:
> The existing PMU emulation code is inadequate for use with nested
> virt. Disable the feature altogether with NV until the hypervisor
> controls are handled correctly.

Could you at least mention *what* is missing? Most of the handling
should identical, and the couple of bits what would need to be
handled (such as MDCR_EL2) are not covered by this disabling.

As it is stands, I'm not there is much to be gained from this.

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...

  reply	other threads:[~2023-10-11 15:54 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-11  8:16 [PATCH 0/2] KVM: arm64: vPMU fixes for NV/EL2 Oliver Upton
2023-10-11  8:16 ` [PATCH 1/2] KVM: arm64: Disallow vPMU for NV guests Oliver Upton
2023-10-11 15:54   ` Marc Zyngier [this message]
2023-10-11 16:43     ` Oliver Upton
2023-10-11  8:16 ` [PATCH 2/2] KVM: arm64: Treat PMEVTYPER<n>_EL0.NSH as RES0 Oliver Upton
2023-10-11 12:33   ` Suzuki K Poulose
2023-10-11 16:17     ` Oliver Upton
2023-10-12 15:33       ` Suzuki K Poulose
2023-10-12  9:43   ` James Clark
2023-10-12 12:47     ` Oliver Upton

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