On 12/14/2012 06:54 AM, Marcelo Tosatti wrote: > On Thu, Dec 13, 2012 at 04:05:55AM +0800, Xiao Guangrong wrote: >> On 12/12/2012 07:36 AM, Marcelo Tosatti wrote: >>> On Mon, Dec 10, 2012 at 05:11:35PM +0800, Xiao Guangrong wrote: >>>> Changelog: >>>> There are some changes from Marcelo and Gleb's review, thank you all! >>>> - access indirect_shadow_pages in the protection of mmu-lock >>>> - fix the issue when unhandleable instruction access on large page >>>> - add a new test case for large page >>>> >>>> The current reexecute_instruction can not well detect the failed instruction >>>> emulation. It allows guest to retry all the instructions except it accesses >>>> on error pfn. >>>> >>>> For example, these cases can not be detected: >>>> - for tdp used >>>> currently, it refused to retry all instructions. If nested npt is used, the >>>> emulation may be caused by shadow page, it can be fixed by unshadow the >>>> shadow page. >>>> >>>> - for shadow mmu >>>> some cases are nested-write-protect, for example, if the page we want to >>>> write is used as PDE but it chains to itself. Under this case, we should >>>> stop the emulation and report the case to userspace. >>>> >>>> There are two test cases based on kvm-unit-test can trigger a infinite loop on >>>> current code (ept = 0), after this patchset, it can report the error to Qemu. >>>> >>>> Subject: [PATCH] access test: test unhandleable instruction >>>> >>>> Test the instruction which can not be handled by kvm >>>> >>>> Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx> >>> >>> Please submit the test for inclusion. There should be some way to make >>> it fail.. >> >> Yes. >> >> But it is not easy. If the test cases run normally, kvm will report a error to Qemu >> then Qemu will exit the vcpu thread after dumping the vcpu state. >> >> We need to do something to let guest can be aware that the error report is triggered. >> I guess we can add a option in Qemu, say '-notify-guest' and allow Qemu to inject #GP >> to guest with a special ERROR_CODE if error is reported. >> >>> program a timer interrupt and #GP? >> >> Could you please explain the detail? > > Before the instruction which writes continuously to the pagetable, arm > say lapic timer. #GP on the interrupt handler and test with failure. Sorry, I am confused about this. After Qemu exits due to KVM_EXIT_INTERNAL_ERROR, the vm is stopped then interrupt can not be injected to guest. Or i missed something? -- 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
