Hi,
just wanted to bump this as I also have the same issue on real HW now (x86_64)
Hi, there!Sorry for the long read ahead, but it seems I've got stuck...I am working on a PV driver and facing an mmap issue.This actually happens when user-space tries to mmapthe memory allocated by the driver:cma_obj->vaddr = dma_alloc_wc(drm->dev, size, &cma_obj->paddr,GFP_KERNEL | __GFP_NOWARN);and maping:vma->vm_flags &= ~VM_PFNMAP;vma->vm_pgoff = 0;ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr, cma_obj->paddr, vma->vm_end - vma->vm_start);Return of the dma_mmap_wc is 0, but I see in the DomU kernel logs:Nov 14 10:30:18 DomU kernel: [ 1169.569909] ------------[ cut here ]------------Nov 14 10:30:18 DomU kernel: [ 1169.569911] WARNING: CPU: 1 PID: 5146 at /home/kernel/COD/linux/arch/x86/xen/multicalls.c:129 xen_mc_flush+0x19c/0x1b0 Nov 14 10:30:18 DomU kernel: [ 1169.569912] Modules linked in: xen_drmfront(OE) drm_kms_helper(OE) drm(OE) fb_sys_fops syscopyarea sysfillrect sysimgblt crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 lrw glue_helper ablk_helper cryptd intel_rapl_perf autofs4 [last unloaded: xen_drmfront]Nov 14 10:30:18 DomU kernel: [ 1169.569919] CPU: 1 PID: 5146 Comm: lt-modetest Tainted: G W OE 4.9.0-040900rc3-generic #201610291831Nov 14 10:30:18 DomU kernel: [ 1169.569920] ffffc900406ffb10 ffffffff81416bf2 0000000000000000 0000000000000000Nov 14 10:30:18 DomU kernel: [ 1169.569923] ffffc900406ffb50 ffffffff8108361b 00000081406ffb30 ffff88003f90b8e0Nov 14 10:30:18 DomU kernel: [ 1169.569925] 0000000000000001 0000000000000010 0000000000000000 0000000000000201Nov 14 10:30:18 DomU kernel: [ 1169.569928] Call Trace:Nov 14 10:30:18 DomU kernel: [ 1169.569930] [<ffffffff81416bf2>] dump_stack+0x63/0x81Nov 14 10:30:18 DomU kernel: [ 1169.569932] [<ffffffff8108361b>] __warn+0xcb/0xf0Nov 14 10:30:18 DomU kernel: [ 1169.569934] [<ffffffff8108374d>] warn_slowpath_null+0x1d/0x20Nov 14 10:30:18 DomU kernel: [ 1169.569936] [<ffffffff8101d60c>] xen_mc_flush+0x19c/0x1b0Nov 14 10:30:18 DomU kernel: [ 1169.569938] [<ffffffff8101d716>] __xen_mc_entry+0xf6/0x150Nov 14 10:30:18 DomU kernel: [ 1169.569940] [<ffffffff81020476>] xen_extend_mmu_update+0x56/0xd0 Nov 14 10:30:18 DomU kernel: [ 1169.569942] [<ffffffff81021d67>] xen_set_pte_at+0x177/0x2f0Nov 14 10:30:18 DomU kernel: [ 1169.569944] [<ffffffff811e064b>] remap_pfn_range+0x30b/0x430Nov 14 10:30:18 DomU kernel: [ 1169.569946] [<ffffffff815a8267>] dma_common_mmap+0x87/0xa0Nov 14 10:30:18 DomU kernel: [ 1169.569953] [<ffffffffc00ffa8f>] drm_gem_cma_mmap_obj+0x8f/0xa0 [drm]Nov 14 10:30:18 DomU kernel: [ 1169.569960] [<ffffffffc00ffac5>] drm_gem_cma_mmap+0x25/0x30 [drm]Nov 14 10:30:18 DomU kernel: [ 1169.569962] [<ffffffff811e79b5>] mmap_region+0x3a5/0x640Nov 14 10:30:18 DomU kernel: [ 1169.569964] [<ffffffff811e8096>] do_mmap+0x446/0x530Nov 14 10:30:18 DomU kernel: [ 1169.569966] [<ffffffff813b88b5>] ? common_mmap+0x45/0x50Nov 14 10:30:18 DomU kernel: [ 1169.569968] [<ffffffff813b8906>] ? apparmor_mmap_file+0x16/0x20Nov 14 10:30:18 DomU kernel: [ 1169.569970] [<ffffffff81377a5d>] ? security_mmap_file+0xdd/0xf0Nov 14 10:30:18 DomU kernel: [ 1169.569972] [<ffffffff811c8faa>] vm_mmap_pgoff+0xba/0xf0Nov 14 10:30:18 DomU kernel: [ 1169.569974] [<ffffffff811e5c01>] SyS_mmap_pgoff+0x1c1/0x290Nov 14 10:30:18 DomU kernel: [ 1169.569976] [<ffffffff8103313b>] SyS_mmap+0x1b/0x30Nov 14 10:30:18 DomU kernel: [ 1169.569978] [<ffffffff8188bbbb>] entry_SYSCALL_64_fastpath+0x1e/0xad Nov 14 10:30:18 DomU kernel: [ 1169.569979] ---[ end trace ce1796cb265ebe08 ]---Nov 14 10:30:18 DomU kernel: [ 1169.569982] ------------[ cut here ]------------And output of xl dmesg says:(XEN) memory.c:226:d0v0 Could not allocate order=9 extent: id=31 memflags=0x40 (488 of 512)(d31) mapping kernel into physical memory(d31) about to get started...(XEN) d31 attempted to change d31v0's CR4 flags 00000620 -> 00040660(XEN) d31 attempted to change d31v1's CR4 flags 00000620 -> 00040660(XEN) traps.c:3657: GPF (0000): ffff82d0801a1a09 -> ffff82d08024b970(XEN) mm.c:1893:d31v0 Bad L1 flags 90(XEN) mm.c:1893:d31v0 Bad L1 flags 90(XEN) mm.c:1893:d31v0 Bad L1 flags 90(XEN) mm.c:1893:d31v0 Bad L1 flags 90My setup is a little bit tricky... I am using a Xen setup runninginside VirtualBox:1. xl info:host : Dom0release : 4.4.0-45-genericversion : #66-Ubuntu SMP Wed Oct 19 14:12:37 UTC 2016machine : x86_64nr_cpus : 2max_cpu_id : 1nr_nodes : 1cores_per_socket : 2threads_per_core : 1cpu_mhz : 3408hw_caps : 178bfbff:d6d82203:28100800:00000121:00000000:00842000: 00000000:00000100 virt_caps :total_memory : 2047free_memory : 11sharing_freed_memory : 0sharing_used_memory : 0outstanding_claims : 0free_cpus : 0xen_major : 4xen_minor : 8xen_extra : .0-rcxen_version : 4.8.0-rcxen_caps : xen-3.0-x86_64 xen-3.0-x86_32pxen_scheduler : creditxen_pagesize : 4096platform_params : virt_start=0xffff800000000000xen_changeset :xen_commandline : placeholdercc_compiler : gcc (Debian 6.2.0-10) 6.2.0 20161027cc_compile_by : ijacksoncc_compile_domain : chiark.greenend.org.ukcc_compile_date : Tue Nov 1 18:11:16 UTC 2016build_id : 3744fa5e7a5b01a0439ba4413e41a7a1c505d5ee xend_config_format : 42. DomULinux DomU 4.9.0-040900rc3-generic #201610291831 SMP Sat Oct 29 22:32:46 UTC 2016 x86_64 x86_64 x86_64 GNU/LinuxCould anyone please give me any hint on what needs tobe checked and how this can be resolved?Thank you,Oleksandr Andrushchenko