[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3] VMX: don't crash processing 'd' debug key
On 11/11/2013 12:55, "Jan Beulich" <JBeulich@xxxxxxxx> wrote: > There's a window during scheduling where "current" and the active VMCS > may disagree: The former gets set much earlier than the latter. Since > both vmx_vmcs_enter() and vmx_vmcs_exit() immediately return when the > subject vCPU is "current", accessing VMCS fields would, depending on > whether there is any currently active VMCS, either read wrong data, or > cause a crash. > > Going forward we might want to consider reducing the window during > which vmx_vmcs_enter() might fail (e.g. doing a plain __vmptrld() when > v->arch.hvm_vmx.vmcs != this_cpu(current_vmcs) but arch_vmx->active_cpu > == -1), but that would add complexities (acquiring and - more > importantly - properly dropping v->arch.hvm_vmx.vmcs_lock) that don't > look worthwhile adding right now. > > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> > Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> This is a little ugly but I can't think of a nicer way. Acked-by: Keir Fraser <keir@xxxxxxx> _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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