Hi Marc, On Sat, 7 Dec 2013 11:19:05 +0000, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: > PSCI is an ARM standard that provides a generic interface that > supervisory software can use to manage power in the following > situations: > - Core idle management > - CPU hotplug > - big.LITTLE migration models > - System shutdown and reset > > It basically allows the kernel to offload these tasks to the firmware, > and rely on common kernel side code. > > More importantly, it gives a way to ensure that CPUs enter the kernel > at the appropriate exception level (ie HYP mode, to allow the use of > the virtualization extensions), even across events like CPUs being > powered off/on or suspended. > > The main idea here is to turn some of the existing u-boot code into a > separate section that can live in secure RAM (or a reserved page of > memory), containing a secure monitor that will implement the PSCI > operations. This code will still be alive when u-boot is long gone, > hence the need for a piece of memory that will not be touched by the > OS. > > This patch series contains 4 parts: > - the first four patches are just bug fixes > - the next three refactor the HYP/non-secure code to allow relocation > in secure memory > - the next three contain the generic PSCI code and DT infrastructure > - the last three implement the CPU_ON method of the Allwinner A20 (aka sun7i). > > I realize the A20 u-boot code is not upstream yet (BTW is anyone > actively working on that?), but hopefully that should give a good idea > of how things are structured so far. The patches are against the sunxi > u-boot tree as of today, and the first 10 patches will directly apply > to mainline u-boot. > > As for using this code, it goes like this: > sun7i# ext2load mmc 0:1 0x40008000 zImage ; ext2load mmc 0:1 0x60000000 sun7i-a20-cubietruck.dtb > 2270120 bytes read in 117 ms (18.5 MiB/s) > 9138 bytes read in 3 ms (2.9 MiB/s) > sun7i# fdt addr 0x60000000 ; fdt resize ; fdt set ethernet0 mac-address "[5a fe b0 07 b0 07]" > sun7i# setenv bootargs console=ttyS0,115200 earlyprintk ip=dhcp root=/dev/nfs nfsroot=/backup/a20_root,tcp > sun7i# bootz 0x40008000 - 0x60000000 > > The kernel now boots in HYP mode, finds its secondary CPU without any > SMP code present in the kernel, and runs KVM out of the box. > Hopefully, the Xen/ARM guys can do the same fairly easily. > > This code has also been tested on a VExpress TC2, running KVM with all > 5 CPUs, in order to make sure there was no obvious regression. > > I'm wildly cross-posting this patch series, including to lists I'm not > subscribed to. Please keep me on Cc for any comment you may have. > > Cheers, > > M. There are comments re 01/13 an 07/13. Should I expect a V3 on the U-Boot ML? Amicalement, -- Albert. _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
