[PATCH v3 22/28] arm64/sve: KVM: Prevent guests from using SVE

[Catalin Marinas]

On Tue, Oct 10, 2017 at 07:38:39PM +0100, Dave P Martin wrote:
> Until KVM has full SVE support, guests must not be allowed to
> execute SVE instructions.
> 
> This patch enables the necessary traps, and also ensures that the
> traps are disabled again on exit from the guest so that the host
> can still use SVE if it wants to.
> 
> This patch introduces another instance of
> __this_cpu_write(fpsimd_last_state, NULL), so this flush operation
> is abstracted out as a separate helper fpsimd_flush_cpu_state().
> Other instances are ported appropriately.
> 
> As a side effect of this refactoring, a this_cpu_write() in
> fpsimd_cpu_pm_notifier() is changed to __this_cpu_write().  This
> should be fine, since cpu_pm_enter() is supposed to be called only
> with interrupts disabled.
> 
> Signed-off-by: Dave Martin <Dave.Martin at arm.com>
> Reviewed-by: Alex Bennée <alex.bennee at linaro.org>
> Cc: Marc Zyngier <marc.zyngier at arm.com>
> Cc: Ard Biesheuvel <ard.biesheuvel at linaro.org>

Acked-by: Catalin Marinas <catalin.marinas at arm.com>