Re: Restoring saved guest causes guest to reboot

[Markus Schade <markus.schade@gmail.com>]

On 05/26/2011 01:28 PM, Markus Schade wrote:
> On 05/26/2011 08:44 AM, Avi Kivity wrote:
>> On 05/25/2011 09:49 AM, Markus Schade wrote:
>>>
>>> Git bisect tells me that this is the first bad commit:
>>> -----------------%<-----------------
>>> aff48baa34c033318ad322ecbf2e4bcd891b29ca is the first bad commit
>>
>> Does your machine have ept?
>>
>> (cat /sys/module/kvm_intel/parameters/ept)
>>
>
> Sure. (Assuming that the Y means yes). I am no C developer, but I was
> wondering, if the issue is related to the difference in
> ept_update_paging_mode_cr0 between original patch in the kvm git and the
> linux-2.6. git tree.

I have re-added the missing 4 lines to ept_update_paging_mode_cr0 in 
vmx.c, which resolves this issue for in Kernel 2.6,37 and 2.6.39.
I haven't tested all guests, but neither Squeeze nor 2008 R2 reboot anymore.

Markus

static void vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer)
@@ -1921,6 +1940,8 @@
                                         unsigned long cr0,
                                         struct kvm_vcpu *vcpu)
  {
+       ulong cr3;
+
         vmx_decache_cr3(vcpu);
         if (!(cr0 & X86_CR0_PG)) {
                 /* From paging/starting to nonpaging */
@@ -1936,8 +1957,11 @@
                              vmcs_read32(CPU_BASED_VM_EXEC_CONTROL) &
                              ~(CPU_BASED_CR3_LOAD_EXITING |
                                CPU_BASED_CR3_STORE_EXITING));
+               /* Must fetch cr3 before updating cr0 */
+               cr3 = kvm_read_cr3(vcpu);
                 vcpu->arch.cr0 = cr0;
                 vmx_set_cr4(vcpu, kvm_read_cr4(vcpu));
+               vmx_set_cr3(vcpu, cr3);