On 04/18/2012 04:47 PM, Nadav Har'El wrote: > On Wed, Apr 18, 2012, Avi Kivity wrote about "Re: [PATCH 0/4] Export offsets of VMCS fields as note information for kdump": > > Right; they're also not required to be in memory at all - the processor > > can cache them, even for VMCSs that are not active at this time. > > Running VMXOFF at panic time can fix that, but you have to broadcast it > > to all processors, probably using NMI... > > I believe that a VMCLEAR ensures that the VMCS is written back to > memory. KVM uses this fact when migrating a VMCS between two separate > physical CPUs - it runs VMCLEAR on the old CPU, to write the VMCS to > memory, and then VMPTRLD on the new CPU. > > So you don't need to VMXOFF, but do need to VMCLEAR. But there's still > the complication that you mention - you need to do the VMCLEAR on the right > processor... VMCLEAR only clears one VMCS; several may be cached by a processor at one time. Presumably VMXOFF flushes everything. -- error compiling committee.c: too many arguments to function
