1. A computer implemented method for reducing translation lookaside buffer (TLB) flushes in a virtualized computing environment, said method comprising: under the control of one or more computer systems configured with executable instructions, allocating one or more virtual memory buffers designated for a central processing unit (CPU) of a plurality of CPUs, each CPU being associated with a translation lookaside buffer (TLB), the one or more virtual memory buffers being allocated in a host domain for performing input/output (I/O) operations; receiving, by a driver in the host domain, a request to perform an I/O operation, the I/O operation associated with one or more physical memory buffers; selecting, by the driver in the host domain, the CPU for performing the I/O operation; requesting, by the driver in the host domain, a mapping of the one or more physical buffers to the one or more virtual buffers allocated for the selected CPU, the requesting indicating that the mapping should not cause a global flush of each TLB in the plurality of other CPUs; obtaining the mapping by the driver of the host domain; requiring that only the selected CPU accesses the one or more physical memory buffers associated with the I/O operation; and if a different CPU will be provided access to the one or more physical memory buffers associated with the I/O operation, requiring the different CPU first perform a flush of the TLB of the different CPU.