On 2013-08-04 15:44, Gleb Natapov wrote: > On Sun, Aug 04, 2013 at 12:53:56PM +0300, Gleb Natapov wrote: >> On Sun, Aug 04, 2013 at 12:32:06PM +0300, Gleb Natapov wrote: >>> On Sun, Aug 04, 2013 at 11:24:41AM +0200, Jan Kiszka wrote: >>>> On 2013-08-01 16:08, Gleb Natapov wrote: >>>>> Another day -- another version of the nested EPT patches. In this version >>>>> included fix for need_remote_flush() with shadowed ept, set bits 6:8 >>>>> of exit_qualification during ept_violation, update_permission_bitmask() >>>>> made to work with shadowed ept pages and other small adjustment according >>>>> to review comments. >>>> >>>> Was just testing it here and ran into a bug: I've L2 accessing the HPET >>>> MMIO region that my L1 passed through from L0 (where it is supposed to >>>> be emulated in this setup). This used to work with an older posting of >>> Not sure I understand your setup. L0 emulates HPET, L1 passes it through >>> to L2 (mmaps it and creates kvm slot that points to it) and when L2 >>> accessed it it locks up? >>> >>>> Jun, but now it locks up (infinite loop over L2's MMIO access, no L2->L1 >>>> transition). Any ideas where to look for debugging this? >>>> >>> Can you do an ftrace -e kvm -e kvmmmu? Unit test will also be helpful :) >>> >> I did an MMIO access from nested guest in the vmx unit test (which is >> naturally passed through to L0 since L1 is so simple) and I can see that >> the access hits L0. >> > But then unit test not yet uses nested EPT :) Indeed, that's what I was about to notice as well. EPT test cases are on Arthur's list, but I suggested to start easier with some MSR switches (just to let him run into KVM's PAT bugs ;) ). Anyway, here are the traces: qemu-system-x86-11521 [000] 4724.170191: kvm_entry: vcpu 0 qemu-system-x86-11521 [000] 4724.170192: kvm_exit: reason EPT_VIOLATION rip 0xffffffff8102ab70 info 181 0 qemu-system-x86-11521 [000] 4724.170192: kvm_page_fault: address 1901978 error_code 181 qemu-system-x86-11521 [000] 4724.170193: kvm_mmu_pagetable_walk: addr 1901978 pferr 0 qemu-system-x86-11521 [000] 4724.170193: kvm_mmu_paging_element: pte 3c04c007 level 4 qemu-system-x86-11521 [000] 4724.170193: kvm_mmu_paging_element: pte 3c04d007 level 3 qemu-system-x86-11521 [000] 4724.170193: kvm_mmu_paging_element: pte 3c05a007 level 2 qemu-system-x86-11521 [000] 4724.170193: kvm_mmu_paging_element: pte 1901037 level 1 qemu-system-x86-11521 [000] 4724.170197: kvm_entry: vcpu 0 qemu-system-x86-11521 [000] 4724.170198: kvm_exit: reason EPT_VIOLATION rip 0xffffffff8102ab77 info 81 0 qemu-system-x86-11521 [000] 4724.170199: kvm_page_fault: address 3a029000 error_code 81 qemu-system-x86-11521 [000] 4724.170199: kvm_mmu_pagetable_walk: addr 3a029000 pferr 0 qemu-system-x86-11521 [000] 4724.170199: kvm_mmu_paging_element: pte 3c04c007 level 4 qemu-system-x86-11521 [000] 4724.170199: kvm_mmu_paging_element: pte 3c04d007 level 3 qemu-system-x86-11521 [000] 4724.170199: kvm_mmu_paging_element: pte 3c21e007 level 2 qemu-system-x86-11521 [000] 4724.170200: kvm_mmu_paging_element: pte 3a029037 level 1 qemu-system-x86-11521 [000] 4724.170203: kvm_entry: vcpu 0 qemu-system-x86-11521 [000] 4724.170204: kvm_exit: reason EPT_VIOLATION rip 0xffffffff8102ab77 info 181 0 qemu-system-x86-11521 [000] 4724.170204: kvm_page_fault: address fed000f0 error_code 181 qemu-system-x86-11521 [000] 4724.170205: kvm_mmu_pagetable_walk: addr fed000f0 pferr 0 qemu-system-x86-11521 [000] 4724.170205: kvm_mmu_paging_element: pte 3c04c007 level 4 qemu-system-x86-11521 [000] 4724.170205: kvm_mmu_paging_element: pte 3c42f003 level 3 qemu-system-x86-11521 [000] 4724.170205: kvm_mmu_paging_element: pte 3c626003 level 2 qemu-system-x86-11521 [000] 4724.170206: kvm_mmu_paging_element: pte fed00033 level 1 qemu-system-x86-11521 [000] 4724.170213: mark_mmio_spte: sptep:0xffff88014e8ad800 gfn fed00 access 6 gen b7f qemu-system-x86-11521 [000] 4724.170214: kvm_mmu_pagetable_walk: addr ffffffff8102ab77 pferr 10 F qemu-system-x86-11521 [000] 4724.170215: kvm_mmu_pagetable_walk: addr 1710000 pferr 6 W|U qemu-system-x86-11521 [000] 4724.170215: kvm_mmu_paging_element: pte 3c04c007 level 4 qemu-system-x86-11521 [000] 4724.170215: kvm_mmu_paging_element: pte 3c04d007 level 3 qemu-system-x86-11521 [000] 4724.170216: kvm_mmu_paging_element: pte 3c059007 level 2 qemu-system-x86-11521 [000] 4724.170216: kvm_mmu_paging_element: pte 1710037 level 1 qemu-system-x86-11521 [000] 4724.170216: kvm_mmu_paging_element: pte 1711067 level 4 qemu-system-x86-11521 [000] 4724.170216: kvm_mmu_walker_error: pferr 19 P|RSVD|F qemu-system-x86-11521 [000] 4724.170217: kvm_emulate_insn: 0:ffffffff8102ab77: qemu-system-x86-11521 [000] 4724.170217: kvm_mmu_pagetable_walk: addr fed000f0 pferr 2 W qemu-system-x86-11521 [000] 4724.170217: kvm_mmu_pagetable_walk: addr 1710000 pferr 6 W|U qemu-system-x86-11521 [000] 4724.170217: kvm_mmu_paging_element: pte 3c04c007 level 4 qemu-system-x86-11521 [000] 4724.170217: kvm_mmu_paging_element: pte 3c04d007 level 3 qemu-system-x86-11521 [000] 4724.170218: kvm_mmu_paging_element: pte 3c059007 level 2 qemu-system-x86-11521 [000] 4724.170218: kvm_mmu_paging_element: pte 1710037 level 1 qemu-system-x86-11521 [000] 4724.170218: kvm_mmu_paging_element: pte 0 level 4 qemu-system-x86-11521 [000] 4724.170218: kvm_mmu_walker_error: pferr 2 W qemu-system-x86-11521 [000] 4724.170219: kvm_entry: vcpu 0 qemu-system-x86-11521 [000] 4724.170220: kvm_exit: reason EPT_MISCONFIG rip 0xffffffff8102ab77 info 0 0 qemu-system-x86-11521 [000] 4724.170221: kvm_mmu_pagetable_walk: addr ffffffff8102ab77 pferr 10 F qemu-system-x86-11521 [000] 4724.170221: kvm_mmu_pagetable_walk: addr 1710000 pferr 6 W|U qemu-system-x86-11521 [000] 4724.170222: kvm_mmu_paging_element: pte 3c04c007 level 4 qemu-system-x86-11521 [000] 4724.170222: kvm_mmu_paging_element: pte 3c04d007 level 3 qemu-system-x86-11521 [000] 4724.170222: kvm_mmu_paging_element: pte 3c059007 level 2 qemu-system-x86-11521 [000] 4724.170222: kvm_mmu_paging_element: pte 1710037 level 1 qemu-system-x86-11521 [000] 4724.170223: kvm_mmu_paging_element: pte 1711067 level 4 qemu-system-x86-11521 [000] 4724.170223: kvm_mmu_walker_error: pferr 19 P|RSVD|F qemu-system-x86-11521 [000] 4724.170223: kvm_emulate_insn: 0:ffffffff8102ab77: The L1 code runs fine as L0 (ie. natively) on the same hardware. Jan
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