On Tue, May 19, 2020, 7:15 PM Tamas K Lengyel <tamas.k.leng...@gmail.com> wrote:
> On Tue, May 19, 2020 at 5:50 PM Roman Shaposhnik <ro...@zededa.com> wrote: > > > > On Tue, May 19, 2020 at 4:44 PM Tamas K Lengyel > > <tamas.k.leng...@gmail.com> wrote: > > > > > > On Tue, May 19, 2020 at 11:23 AM Julien Grall <jul...@xen.org> wrote: > > > > > > > > > > > > > > > > On 19/05/2020 04:08, Tamas K Lengyel wrote: > > > > > On Mon, May 18, 2020 at 5:32 AM Julien Grall <jul...@xen.org> > wrote: > > > > >> > > > > >> From: Julien Grall <jgr...@amazon.com> > > > > >> > > > > >> Hi all, > > > > >> > > > > >> At the moment, a user who wants to boot Xen on the Raspberry Pi 4 > can > > > > >> only use the first GB of memory. > > > > >> > > > > >> This is because several devices cannot DMA above 1GB but Xen > doesn't > > > > >> necessarily allocate memory for Dom0 below 1GB. > > > > >> > > > > >> This small series is trying to address the problem by allowing a > > > > >> platform to restrict where Dom0 banks are allocated. > > > > >> > > > > >> This is also a candidate for Xen 4.14. Without it, a user will > not be > > > > >> able to use all the RAM on the Raspberry Pi 4. > > > > >> > > > > >> This series has only be slighlty tested. I would appreciate more > test on > > > > >> the Rasbperry Pi 4 to confirm this removing the restriction. > > > > > > > > > > Hi Julien, > > > > > > > > Hi, > > > > > > > > > could you post a git branch somewhere? I can try this on my rpi4 > that > > > > > already runs 4.13. > > > > > > > > I have pushed a branch based on unstable and the v2 of the series: > > > > > > > > git://xenbits.xen.org/people/julieng/xen-unstable.git > > > > > > > > branch arm-dma/v2 > > > > > > > > > > I've updated my image I built with > > > https://github.com/tklengyel/xen-rpi4-builder a while ago and I've > > > defined 2048m as total_mem and Xen seems to be booting fine and passes > > > execution to dom0. With 512m being set as the Xen cmdline for dom0_mem > > > it was working. When I increased the mem for dom0 the boot is now > > > stuck at: > > > > > > [ 1.427788] of_cfs_init > > > [ 1.429667] of_cfs_init: OK > > > [ 1.432561] clk: Not disabling unused clocks > > > [ 1.437239] Waiting for root device /dev/mmcblk0p2... > > > [ 1.451599] mmc1: queuing unknown CIS tuple 0x80 (2 bytes) > > > [ 1.458156] mmc1: queuing unknown CIS tuple 0x80 (3 bytes) > > > [ 1.464729] mmc1: queuing unknown CIS tuple 0x80 (3 bytes) > > > [ 1.472804] mmc1: queuing unknown CIS tuple 0x80 (7 bytes) > > > [ 1.479370] mmc1: queuing unknown CIS tuple 0x80 (3 bytes) > > > [ 1.546902] random: fast init done > > > [ 1.564590] mmc1: new high speed SDIO card at address 0001 > > > > > > Could this be because the DTB I compiled from a fresh checkout of > > > https://github.com/raspberrypi/linux.git branch rpi-4.19.y whereas the > > > kernel itself is from a checkout ~5 months ago? I guess that must be > > > the cause because even if I decrease the dom0_mem to 512m it still > > > gets stuck at the same spot whereas it was booting fine before. > > > > Stefano and I are testing the fix right now -- for now just set your > > Dom0 mem to less than 512m. > > Actually seems to work after I recompiled the kernel and reinstalled > all kernel modules. Xen boots with 4gb RAM and dom0 boots with 2g: > > xl info: > ... > total_memory : 3956 > free_memory : 1842 > > cat /proc/meminfo > MemTotal: 1963844 kB > > I get an emergency shell during boot on the console complaining about > xenbr0 not coming up but if I just hit continue it boots fine and the > network is up. So AFAICT things are good. > What exact version of the kernel are you using and what did you build it from? FWIW: 5.6.x clearly has an issue with DMA. Thanks, Roman. >
