On Fri, Apr 17, 2020 at 09:37:49PM -0700, Sean Christopherson wrote: > On Tue, Mar 31, 2020 at 12:13:36AM +0300, Jarkko Sakkinen wrote: > > On Mon, Mar 30, 2020 at 09:54:52PM +0300, Jarkko Sakkinen wrote: > > > sgx_encl_may_map() always succeeding when PROT_NONE is given is not that > > > useful behaviour as one can just well as do an anonymous mapping as > > > demonstrated by the change in this patch to the test program. As a > > > consequence, remove the special case. > > > > > > Pratically any possible way to make sure that you don't overwrite anything > > > useful in the memory, should be fine. MAP_FIXED does not care what's > > > underneath (if you want't it to care you ought to use > > > MAP_FIXED_NO_REPLACE). > > > > > > After this change, the selftest run called sgx_mmap() only three times > > > (TCS, text, data) instead of four. > > > > > > test_sgx-1811 [002] .... 586.907585: sgx_mmap <-mmap_region > > > test_sgx-1811 [002] .... 586.911752: sgx_mmap <-mmap_region > > > test_sgx-1811 [002] .... 586.911756: sgx_mmap <-mmap_region > > > > > > This also gives more angles to segregate enclave building and mapping as > > > the mmap()'s need to be applied only when the enclave is fully built: > > > > > > Cc: luto@xxxxxxxxxx > > > Cc: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx> > > > Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> > > > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx> > > > > Sean, would be cool if you can try this out soonish because I'm > > building on top of this. > > Two and a half weeks is soonish, right? > > Anyways, finally tested this, no issues. Just to be different than the > selftest, I used MAP_PRIVATE instead of MAP_SHARED along with MAP_ANONYMOUS > in my test code. Ah, MAP_SHARED was not intentional. Not gonna change it tho because both should equally work (or basically anything to guarante the availability of the address space). /Jarkko
