Re: [PATCH] drm/msm/a6xx: Skip gpu secure fw load in EL2 mode

[Pavan Kondeti <quic_pkondeti@quicinc.com>]

On Tue, Dec 10, 2024 at 09:24:03PM +0000, Marc Zyngier wrote:
> > +static int a6xx_switch_secure_mode(struct msm_gpu *gpu)
> > +{
> > +	int ret;
> > +
> > +#ifdef CONFIG_ARM64
> > +	/*
> > +	 * We can access SECVID_TRUST_CNTL register when kernel is booted in EL2 mode. So, use it
> > +	 * to switch the secure mode to avoid the dependency on zap shader.
> > +	 */
> > +	if (is_kernel_in_hyp_mode())
> > +		goto direct_switch;
> 
> No, please. To check whether you are *booted* at EL2, you need to
> check for is_hyp_available(). Whether the kernel runs at EL1 or EL2 is
> none of the driver's business, really. This is still absolutely
> disgusting from an abstraction perspective, but I guess we don't have
> much choice here.
> 

Thanks Marc. Any suggestions on how we can make is_hyp_mode_available()
available for modules? Do you prefer exporting
kvm_protected_mode_initialized and __boot_cpu_mode symbols directly or
try something like [1]?

[1]
https://lore.kernel.org/lkml/1443649252-10702-1-git-send-email-ralf@ramses-pyramidenbau.de/#t

Thanks,
Pavan