On Aug 4, 2013, at 11:14 PM, Jan Kiszka <jan.kiszka@xxxxxx> wrote:
> 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
I guess the bug is here, could you please change this code to:
- if (unlikely(is_rsvd_bits_set(&vcpu->arch.mmu, pte,
+ if (unlikely(is_rsvd_bits_set(mmu, pte,
walker->level))) {
(
In static int FNAME(walk_addr_generic)(struct guest_walker *walker,
struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
gva_t addr, u32 access)
)
and try again?
--
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
