Jan Kiszka wrote:
Hi, turning on MMU_DEBUG and AUDIT in arch/x86/kvm/mmu.c (and fixing a build error, patch will follow) I got this (and then a #GP :( - patch will follow): ... kvm_mmu_get_page: looking gfn 0 role f0120 kvm_mmu_get_page: found kvm_mmu_get_page: looking gfn 0 role f0220 kvm_mmu_get_page: found kvm_mmu_get_page: looking gfn 0 role f0320 kvm_mmu_get_page: found kvm_mmu_get_page: looking gfn e1f role e0044 kvm_mmu_get_page: adding gfn e1f role e0044 rmap_write_protect: spte ffff8100660a60f8 7ca98067 paging64_page_fault: addr 100105 err 19 audit_write_protection: (pre page fault) shadow page has writable mappings: gfn e1f role e0044 audit: (pre page fault) nontrapping pte in nonleaf level: levels 4 gva 8000000000 level 4 pte 0 Is the last message indicating a problem? I get it very early during guest boot. oos_shadow is disabled.
Yes. It means the guest will receive a page fault if is accesses anything this pte points to. Theoretically we could have made this work, but we never did.
But the message is self-contradictory. Level 4 PTEs map 0.5TB each, and the gva mentioned isn't 0.5TB aligned.
I'm currently trying to understand an obvious inconsistency in the pte describing a page of the virtio-net rx ring. On some guests with some qemu (upstream) command lines I can trigger this with '-smb /some/path' and then doing smbclient -L in the guest. Once the inconsistency slipped in, host and guest see different page contents and virtio-net stops to work. Very strange, but fortunately easily reproducible here. Any hints or debugging suggestions welcome!
What type of inconsistency? pfn or flags? -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
