On Fri, Oct 22, 2021 at 11:46:30PM +0200, Paolo Bonzini wrote:
> On 22/10/21 21:27, Yang Zhong wrote:
> >+
> >+ for (j = 0; j < num; j++) {
> >+ epc = pcms->sgx_epc.sections[j];
> >+ hostmem = MEMORY_BACKEND(epc->hostmem);
> >+ fd = memory_region_get_fd(host_memory_backend_get_memory(hostmem));
> >+
> >+ failures = ioctl(fd, SGX_IOC_VEPC_REMOVE_ALL);
> >+ if (failures < 0) {
> >+ return failures;
> >+ } else if (failures > 0) {
> >+ /* Remove SECS pages */
> >+ sleep(1);
> >+ failures_1 = ioctl(fd, SGX_IOC_VEPC_REMOVE_ALL);
> >+ }
> >+
> >+ /*
> >+ * The host or guest can support 8 EPC sections, use the
> >+ * corresponding bit to show each section removal status.
> >+ */
> >+ if (failures_1) {
> >+ set_bit(j, &ret);
> >+ }
> >+ }
>
> This sleep is not necessary, just do two tries on all the regions.
> So something like
>
> int failures;
>
> /*
> * The second pass is needed to remove SECS pages that could not
> * be removed during the first.
> */
> for (i = 0; i < 2; i++) {
> failures = 0;
> for (j = 0; j < pcms->sgx_epc.nr_sections; j++) {
> epc = pcms->sgx_epc.sections[j];
> hostmem = MEMORY_BACKEND(epc->hostmem);
> fd =
> memory_region_get_fd(host_memory_backend_get_memory(hostmem));
>
> r = ioctl(fd, SGX_IOC_VEPC_REMOVE_ALL);
> if (r < 0) {
> return r;
> }
> if (r > 0) {
> /* SECS pages remain */
> failures++;
> if (pass == 1) {
> error_report("cannot reset vEPC section %d\n", j);
> }
> }
> }
> if (!failures) {
> return 0;
> }
> }
> return failures;
>
> is enough, without any need to do further retries.
>
Thanks Paolo, i will update it in the next version. Please also
help review other patches, thanks!
Yang
> Paolo
