On Tuesday 26 November 2013 12:37 PM, Dave Martin wrote: > On Tue, Nov 26, 2013 at 09:47:13AM -0500, Santosh Shilimkar wrote: >> On Tuesday 26 November 2013 09:13 AM, Catalin Marinas wrote: >>> On Mon, Nov 25, 2013 at 07:44:08PM +0000, Santosh Shilimkar wrote: >>>> On Monday 25 November 2013 12:28 PM, Catalin Marinas wrote: >>>>> On Mon, Nov 25, 2013 at 04:59:16PM +0000, Santosh Shilimkar wrote: >>>>>> What I am saying is the platforms like OMAP5 already support PM in >>>>>> mainline kernel and we can't break that for KVM. Boot-loaders >>>>>> would be thrashed after boot so you need something which runs >>>>>> in Kernel or along with Kernel to have equivalent of hyp >>>>>> switching. >>>>>> >>>>>> Am not challenging the agreed direction but we need to solve the >>>>>> PM problem as well before making "all CPU runs boot-loader for >>>>>> HYP kernels" as a must have. At least its is a change in boot >>>>>> strategy from existing kernels. >>>>> >>>>> Of course I recommend PSCI which covers both hotplug and suspend ;), but >>>>> I guess it's not the case for OMAP5. Since OMAP has its own secondary >>>>> booting protocol and CPU hotplug re-entry, can you not just use >>>>> different entry point when the primary CPU was initially started in Hyp >>>>> mode (e.g. omap5_hyp_secondary_startup)? >>>>> >>>> How will that solve the guest secondary boot failure case when using >>>> the same kernel binary for guest-boot ? Even for primary CPU which >>>> will be suspended it needs to resume already in HYP mode and its not >>>> going to go through boot-loader. So the low power code needs to have >>>> HYP switch code so that CPU resumes in HYP mode. >>> >>> Is it late to rewrite the OMAP5 firmware? >>> >> Well its ROM'ed unfortunately so no choice. OMAP5 ROM did implement >> a secure API which lets you enter into HYP mode and thats the only >> thing can be used. > > If the ROM is capable of loading some additional signed Secure World > firmware after the ROM itself has booted, PSCI could be implemented > in the second, resident firmware payload. > > Some SoCs ship with boot ROMs that can do that -- is this not the case > for OMAP5? > On OMAP, the secure devices there is a way to do this but not for general purpose devices. General purpose devices once you exit the ROM code, we exit out of security and only way to re-enter secure word is via ROM implemented monitor/secure APIs. regards, Santosh -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
