[PATCH v2] KVM: arm64: Don't populate TPIDR_EL2 in finalise_el2()
Marc Zyngier
maz at kernel.org
Mon May 18 08:39:30 PDT 2026
On Mon, 18 May 2026 16:31:26 +0100,
Will Deacon <will at kernel.org> wrote:
>
> Currently, it is not necessary for __finalise_el2() to configure
> TPIDR_EL2:
>
> * The hyp stub code does not consume the value of TPIDR_EL2.
>
> * On the boot cpu, TPIDR_EL1 is used for the percpu offset until the
> ARM64_HAS_VIRT_HOST_EXTN cpucap is detected and boot alternatives
> are patched. Before boot alternatives are patched,
> cpu_copy_el2regs() will copy TPIDR_EL1 into TPIDR_EL2. It is not
> necessary for __finalise_el2() to initialise TPIDR_EL2 before this.
>
> * Secondary CPUs are brought up after boot alternatives have been
> patched, and __secondary_switched() will initialize TPIDR_EL2 in
> 'init_cpu_task', after finalise_el2() calls __finalise_el2()
>
> * KVM hyp code which may consume TPIDR_EL2 is brought up after all
> secondaries have been booted, once TPIDR_El2 has been configured on
> all CPUs.
>
> Remove the redundant initialisation from __finalise_el2().
>
> Cc: Oliver Upton <oupton at kernel.org>
> Cc: Marc Zyngier <maz at kernel.org>
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Reviewed-by: Mark Rutland <mark.rutland at arm.com>
> Signed-off-by: Will Deacon <will at kernel.org>
Reviewed-by: Marc Zyngier <maz at kernel.org>
M.
--
Without deviation from the norm, progress is not possible.
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