On 12/9/2024 8:33 PM, Konrad Dybcio wrote: > On 9.12.2024 9:19 AM, Akhil P Oommen wrote: >> When kernel is booted in EL2, SECVID registers are accessible to the >> KMD. So we can use that to switch GPU's secure mode to avoid dependency >> on Zap firmware. Also, we can't load a secure firmware without a >> hypervisor that supports it. >> >> Tested following configurations on sa8775p chipset (Adreno 663 gpu): >> >> 1. Gunyah (No KVM) - Loads zap shader based on DT >> 2. KVM in VHE - Skips zap shader load and programs SECVID register >> 3. KVM in nVHE - Loads zap shader based on DT >> 4. Kernel in EL2 with CONFIG_KVM=n - Skips zap shader load and >> programs SECVID register >> >> For (1) and (3) configuration, this patch doesn't have any impact. >> Driver loads secure firmware based on other existing hints. >> >> Signed-off-by: Akhil P Oommen <quic_akhilpo@xxxxxxxxxxx> >> --- > > [...] > >> + >> +#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; > > So I suppose this would ideally be like hv_is_hyperv_initialized() > but for QHEE/Gunyah, which is not going to happen, as we have > millions of devices with old unupstreamable-ABI-Gunyah running.. > > This looks like the next best things then, so no objections, but.. > > [...] > >> + ret = a6xx_switch_secure_mode(gpu); >> + if (!ret) > > this should definitely be a if (ret) My bad! Thanks. -Akhil. > > Konrad
