Re: [PATCH 6.12 3/8] KVM: arm64: Remove host FPSIMD saving for non-protected KVM
From: Catalin Marinas
Date: Fri Mar 14 2025 - 10:41:10 EST
On Fri, Mar 14, 2025 at 06:32:45AM +0100, Greg Kroah-Hartman wrote:
> On Fri, Mar 14, 2025 at 12:35:15AM +0000, Mark Brown wrote:
> > From: Mark Rutland <mark.rutland@xxxxxxx>
> >
> > 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@xxxxxxx>
> > Reviewed-by: Mark Brown <broonie@xxxxxxxxxx>
> > Tested-by: Mark Brown <broonie@xxxxxxxxxx>
> > Acked-by: Will Deacon <will@xxxxxxxxxx>
> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> > Cc: Fuad Tabba <tabba@xxxxxxxxxx>
> > Cc: Marc Zyngier <maz@xxxxxxxxxx>
> > Cc: Oliver Upton <oliver.upton@xxxxxxxxx>
> > Reviewed-by: Oliver Upton <oliver.upton@xxxxxxxxx>
> > Link: https://lore.kernel.org/r/20250210195226.1215254-3-mark.rutland@xxxxxxx
> > Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> > Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
> > ---
>
> What is the upstream git id for this on?
It seems to be 8eca7f6d5100 ("KVM: arm64: Remove host FPSIMD saving for
non-protected KVM").
--
Catalin