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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: Question about xen and Rasp 4B
On Fri, 29 Jan 2021, Julien Grall wrote: > Hi, > > @Jukka, would it be possible to at least configure your client to quote with > '>'? This would make easier to understand who wrote what (tabulation is not > great for that). > > If you are using gmail, then configuring it to send it as plain text should do > the job. > > On 27/01/2021 11:47, Jukka Kaartinen wrote: > > > > > > On Tue, Jan 26, 2021 at 10:22 PM Stefano Stabellini <sstabellini@xxxxxxxxxx > > <mailto:sstabellini@xxxxxxxxxx>> wrote: > > > > On Tue, 26 Jan 2021, Jukka Kaartinen wrote: > > > On Tue, Jan 26, 2021 at 2:54 AM Stefano Stabellini > > <sstabellini@xxxxxxxxxx <mailto:sstabellini@xxxxxxxxxx>> wrote: > > > On Sat, 23 Jan 2021, Jukka Kaartinen wrote: > > > > Thanks for the response! > > > > > > > > On Sat, Jan 23, 2021 at 2:27 AM Stefano Stabellini > > <sstabellini@xxxxxxxxxx <mailto:sstabellini@xxxxxxxxxx>> wrote: > > > > + xen-devel, Roman, > > > > > > > > > > > > On Fri, 22 Jan 2021, Jukka Kaartinen wrote: > > > > > Hi Stefano, > > > > > I'm Jukka Kaartinen a SW developer working on > > enabling hypervisors on mobile platforms. One of our HW that we use on > > > > development is > > > > > Raspberry Pi 4B. I wonder if you could help me a > > bit :). > > > > > > > > > > I'm trying to enable the GPU with Xen + Raspberry > > Pi for > > > > dom0. > > https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=232323#p1797605 > > > > <https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=232323#p1797605> > > > > > > > > > > I got so far that GPU drivers are loaded (v3d & > > vc4) without errors. But now Xen returns error when X is starting: > > > > > (XEN) traps.c:1986:d0v1 HSR=0x93880045 > > pc=0x00007f97b14e70 gva=0x7f7f817000 gpa=0x0000401315d000 > > > > > I tried to debug what causes this and looks > > like find_mmio_handler cannot find handler. > > > > > (See more here: > > > > https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=232323&start=25#p1801691 > > > > <https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=232323&start=25#p1801691> > > ) > > > > > > > > > > Any ideas why the handler is not found? > > > > > > > > > > > > Hi Jukka, > > > > > > > > I am glad to hear that you are interested in Xen on > > RaspberryPi :-) I > > > > haven't tried the GPU yet, I have been using the > > serial only. > > > > Roman, did you ever get the GPU working? > > > > > > > > > > > > The error is a data abort error: Linux is trying to > > access an address > > > > which is not mapped to dom0. The address seems to > > be 0x401315d000. It is > > > > a pretty high address; I looked in device tree but > > couldn't spot it. > > > > > > > > >From the HSR (the syndrom register) it looks like > > it is a translation > > > > fault at EL1 on stage1. As if the Linux address > > mapping was wrong. > > > > Anyone has any ideas how this could happen? Maybe a > > reserved-memory > > > > misconfiguration? > > > > > > > > I had issues with loading the driver in the first place. > > Apparently swiotlb is used, maybe it can cause this. I also tried to > > > enable CMA. > > > > config.txt: > > > > dtoverlay=vc4-fkms-v3d,cma=320M@0x0-0x40000000 > > > > gpu_mem=128 > > > > > > Also looking at your other reply and the implementation of > > > vc4_bo_create, it looks like this is a CMA problem. > > > > > > It would be good to run a test with the swiotlb-xen disabled: > > > > > > diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c > > > index 467fa225c3d0..2bdd12785d14 100644 > > > --- a/arch/arm/xen/mm.c > > > +++ b/arch/arm/xen/mm.c > > > @@ -138,8 +138,7 @@ void > > xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order) > > > static int __init xen_mm_init(void) > > > { > > > struct gnttab_cache_flush cflush; > > > - if (!xen_initial_domain()) > > > - return 0; > > > + return 0; > > > xen_swiotlb_init(1, false); > > > > > > cflush.op = 0; > > > > > > With this change the kernel is not booting up. (btw. I'm using > > USB SSD for my OS.) > > > [ 0.071081] bcm2835-dma fe007000.dma: Unable to set DMA mask > > > [ 0.076277] bcm2835-dma fe007b00.dma: Unable to set DMA mask > > > (XEN) physdev.c:16:d0v0 PHYSDEVOP cmd=25: not implemented > > > (XEN) physdev.c:16:d0v0 PHYSDEVOP cmd=15: not implemented > > > [ 0.592695] pci 0000:00:00.0: Failed to add - passthrough or > > MSI/MSI-X might fail! > > > (XEN) physdev.c:16:d0v0 PHYSDEVOP cmd=15: not implemented > > > [ 0.606819] pci 0000:01:00.0: Failed to add - passthrough or > > MSI/MSI-X might fail! > > > [ 1.212820] usb 1-1: device descriptor read/64, error 18 > > > [ 1.452815] usb 1-1: device descriptor read/64, error 18 > > > [ 1.820813] usb 1-1: device descriptor read/64, error 18 > > > [ 2.060815] usb 1-1: device descriptor read/64, error 18 > > > [ 2.845548] usb 1-1: device descriptor read/8, error -61 > > > [ 2.977603] usb 1-1: device descriptor read/8, error -61 > > > [ 3.237530] usb 1-1: device descriptor read/8, error -61 > > > [ 3.369585] usb 1-1: device descriptor read/8, error -61 > > > [ 3.480765] usb usb1-port1: unable to enumerate USB device > > > > > > Traces stop here. I could try with a memory card. Maybe it makes > > a difference. > > > > This is very surprising. Disabling swiotlb-xen should make things better > > not worse. The only reason I can think of why it could make things worse > > is if Linux runs out of low memory. Julien's patch > > 437b0aa06a014ce174e24c0d3530b3e9ab19b18b for Xen should have addressed > > that issue though. Julien, any ideas? > > I think, Stefano's small patch is not enough to disable the swiotlb as we will > still override the DMA ops. You also likely want: > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c > index 8a8949174b1c..aa43e249ecdd 100644 > --- a/arch/arm/mm/dma-mapping.c > +++ b/arch/arm/mm/dma-mapping.c > @@ -2279,7 +2279,7 @@ void arch_setup_dma_ops(struct device *dev, u64 > dma_base, u64 size, > set_dma_ops(dev, dma_ops); > > #ifdef CONFIG_XEN > - if (xen_initial_domain()) > + if (0 || xen_initial_domain()) > dev->dma_ops = &xen_swiotlb_dma_ops; > #endif > dev->archdata.dma_ops_setup = true; > > Otherwise, you would still use the swiotlb DMA ops that would not be > functional as we disabled the swiotlb. > > This would explain the following error because it will check whether the mask > is valid using the callback dma_supported(): > > [ 0.071081] bcm2835-dma fe007000.dma: Unable to set DMA mask Well spotted! On older kernels the change to xen_mm_init was sufficient, but on more recent kernels it is not enough anymore. Sorry about that! BTW if (0 || xen_initial_domain()) would still return true so you might want something like: diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index 93e87b287556..f73066bed3ec 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -53,7 +53,7 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, iommu_setup_dma_ops(dev, dma_base, size); #ifdef CONFIG_XEN - if (xen_initial_domain()) + if (0) dev->dma_ops = &xen_swiotlb_dma_ops; #endif }
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