2018-02-08 0:57 GMT+08:00 Jim Mattson <jmattson@xxxxxxxxxx>: > vmcs12->host_cr[34] does not contain the up-to-date values when L1 is > running. L1 can vmwrite any values there. We know at this point that It will incur a vmexit to emulate L1 vmwrites vmcs12->host_cr[34] even if vmcs shadow is enabled since host_cr[34] is not shadowed in the bitmap, why it is not up-to-date when L1 is running? Regards, Wanpeng Li > they are legal (because we checked them), but that's about it. If the > VMLAUNCH/VMRESUME of vmcs12 fails for "invalid control field," there > is no VM-exit from L2 to L1, and these fields are not loaded. Instead, > execution just falls through to the next instruction with VMFailValid > semantics. > > On Wed, Feb 7, 2018 at 12:31 AM, Wanpeng Li <kernellwp@xxxxxxxxx> wrote: >> 2018-02-07 0:58 GMT+08:00 Jim Mattson <jmattson@xxxxxxxxxx>: >>> On Mon, Feb 5, 2018 at 4:57 PM, Wanpeng Li <kernellwp@xxxxxxxxx> wrote: >>> >>>> This is effective one, what I restore in this patch is >>>> achitectural/guest visible. >>> >>> This patch doesn't "restore" the guest visible CR4 to its value at the >>> time of VMLAUNCH/VMRESUME. It loads a new CR4 value from the vmcs12. >>> That behavior is incorrect. >> >> You have another pointing out about this. >> https://lkml.org/lkml/2018/2/5/518 vmcs12->host_cr3/host_cr4 has the >> up-to-date value when L1 is running, it is still up-to-date after >> vmexit due to L1 executes VMLAUNCH/VMRESUME, I think the value stays >> the same before L0 emulates the VMLAUNCH/VMRESUME, according to below >> comments, why vmcs12->host_cr3/cr4 is not the value which we should >> restore? >> >> * After an early L2 VM-entry failure, we're now back >> * in L1 which thinks it just finished a VMLAUNCH or >> * VMRESUME instruction >> >> Regards, >> Wanpeng Li
