Sorry for the late reply. Seems to me that the EPTP pointer is changing because of kvm_set_cr0. Here is what I did and please correct me if I am doing the trace incorrectly: - Added a trace entry in vmx_set_cr3 where a trace message is outputted whenever vmcs_read64(EPT_POINTER) != eptp after construct_eptp(cr3). I then looked at the trace log and seems to show up with kvm_exit: reason cr_access rip 0xc0122003 kvm_cr: cr_write 0 = 0x8005003b I also noticed that kvm_mmu_reset_context(vcpu) is being called at the end of kvm_set_cr0. The CR0 value of 0x8005003b doesn't seem to trigger any of the if cases which would indicate that kvm_mmu_reset_context(vcpu) is being called and could be the reason why eptp is changing. Thanks for your help again. Enjoy, Lok ________________________________________ From: Avi Kivity [avi@xxxxxxxxxx] Sent: Sunday, December 19, 2010 9:31 AM To: Lok Kwong Yan Cc: Anthony Liguori; kvm@xxxxxxxxxxxxxxx Subject: Re: Does KVM use one EPT table per Guest CR3? On 12/17/2010 05:24 PM, Avi Kivity wrote: > On 12/17/2010 12:14 AM, Lok Kwong Yan wrote: >> Thanks for the reply and it makes a lot of sense. >> >> I am not seeing any EPT tables being zapped after the guest has fully >> started up although the value of EPTP continuously changes as the >> guest is running. > > Really strange, this is likely a bug. > I tried to reproduce, the only times I see eptp changes are when the guest reprograms the vga adapter: qemu-system-x86-20944 [033] 1327.151819: kvm_pio: pio_write at 0x3ce size 2 count 1 qemu-system-x86-20944 [033] 1327.151819: kvm_userspace_exit: reason KVM_EXIT_IO (2) qemu-system-x86-20944 [033] 1327.152405: kvm_mmu_prepare_zap_page: [FAILED TO PARSE] gfn=237568 role=122881 root_count=0 unsync=0 ... qemu-system-x86-20944 [033] 1327.153230: kvm_mmu_prepare_zap_page: [FAILED TO PARSE] gfn=0 role=253956 root_count=2 unsync=0 qemu-system-x86-20944 [033] 1327.153339: kvm_mmu_get_page: sp gfn 0 0/4 q0 direct --- !pge !nxe root 0sync qemu-system-x86-20944 [033] 1327.153344: print: a0265cde vmx_set_cr3: eptp fef14101 Under what scenario do you see eptp changing? -- 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
