linux-kernel - Re: [PATCH 6.12 3/8] KVM: arm64: Remove host FPSIMD saving for non-protected KVM

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Message-ID: <2025031427-yiddish-unrented-2bc2@gregkh>
Date: Fri, 14 Mar 2025 06:32:45 +0100
From: Greg KH <gregkh@...uxfoundation.org>
To: Mark Brown <broonie@...nel.org>
Cc: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>,
	Joey Gouly <joey.gouly@....com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>, linux-arm-kernel@...ts.infradead.org,
	kvmarm@...ts.linux.dev, linux-kernel@...r.kernel.org,
	stable@...r.kernel.org, Mark Rutland <mark.rutland@....com>,
	Fuad Tabba <tabba@...gle.com>
Subject: Re: [PATCH 6.12 3/8] KVM: arm64: Remove host FPSIMD saving for
 non-protected KVM

On Fri, Mar 14, 2025 at 12:35:15AM +0000, Mark Brown wrote:
> From: Mark Rutland <mark.rutland@....com>
> 
> Now that the host eagerly saves its own FPSIMD/SVE/SME state,
> non-protected KVM never needs to save the host FPSIMD/SVE/SME state,
> and the code to do this is never used. Protected KVM still needs to
> save/restore the host FPSIMD/SVE state to avoid leaking guest state to
> the host (and to avoid revealing to the host whether the guest used
> FPSIMD/SVE/SME), and that code needs to be retained.
> 
> Remove the unused code and data structures.
> 
> To avoid the need for a stub copy of kvm_hyp_save_fpsimd_host() in the
> VHE hyp code, the nVHE/hVHE version is moved into the shared switch
> header, where it is only invoked when KVM is in protected mode.
> 
> Signed-off-by: Mark Rutland <mark.rutland@....com>
> Reviewed-by: Mark Brown <broonie@...nel.org>
> Tested-by: Mark Brown <broonie@...nel.org>
> Acked-by: Will Deacon <will@...nel.org>
> Cc: Catalin Marinas <catalin.marinas@....com>
> Cc: Fuad Tabba <tabba@...gle.com>
> Cc: Marc Zyngier <maz@...nel.org>
> Cc: Oliver Upton <oliver.upton@...ux.dev>
> Reviewed-by: Oliver Upton <oliver.upton@...ux.dev>
> Link: https://lore.kernel.org/r/20250210195226.1215254-3-mark.rutland@arm.com
> Signed-off-by: Marc Zyngier <maz@...nel.org>
> Signed-off-by: Mark Brown <broonie@...nel.org>
> ---

What is the upstream git id for this on?

thanks,

greg k-h