On Fri, 2021-09-03 at 09:56 +1200, Kai Huang wrote: > On Thu, 02 Sep 2021 15:15:51 +0300 Jarkko Sakkinen wrote: > > On Wed, 2021-09-01 at 17:47 +1200, Kai Huang wrote: > > > On Wed, 01 Sep 2021 08:41:12 +0300 Jarkko Sakkinen wrote: > > > > On Wed, 2021-09-01 at 17:33 +1200, Kai Huang wrote: > > > > > On Wed, 01 Sep 2021 05:02:45 +0300 Jarkko Sakkinen wrote: > > > > > > On Sat, 2021-08-28 at 00:03 +1200, Kai Huang wrote: > > > > > > > > > > -/* The free page list lock protected variables prepend the lock. */ > > > > > > > > > > +/* The number of usable EPC pages in the system. */ > > > > > > > > > > +unsigned long sgx_nr_all_pages; > > > > > > > > > > + > > > > > > > > > > +/* The number of free EPC pages in all nodes. */ > > > > > > > > > > static unsigned long sgx_nr_free_pages; > > > > > > > > > > > > > > > > > > > > /* Nodes with one or more EPC sections. */ > > > > > > > > > > @@ -656,6 +659,8 @@ static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size, > > > > > > > > > > list_add_tail(§ion->pages[i].list, &sgx_dirty_page_list); > > > > > > > > > > } > > > > > > > > > > > > > > > > > > > > + sgx_nr_all_pages += nr_pages; > > > > > > > > > > + > > > > > > > > > > > > > > > > > > EPC sections can be freed again in sgx_init() after they are successfully > > > > > > > > > initialized, when any further initialization fails (i.e. when fails to create > > > > > > > > > ksgxd, or fails to register /dev/sgx_provision). In which case, I think > > > > > > > > > sgx_nr_all_pages should also be cleared. But current sgx_init() seems doesn't > > > > > > > > > reset it. Do you need to fix that too? > > > > > > > > > > > > > > > > sgx_nr_all_pages tells just the total pages in the system, i.e. it's a constant. > > > > > > > > > > > > > > > > Maybe a rename to "sgx_nr_total_pages" would be a good idea? Would match with > > > > > > > > the meminfo field better too. > > > > > > > > > > > > > > I don't have preference on name. I just think if there's no actual user of > > > > > > > EPC (when both driver and KVM SGX cannot be enabled), it's pointless to print > > > > > > > number of EPC pages. > > > > > > > > > > > > I'd presume that you refer to the code, which prints the number of *bytes* in > > > > > > the system because code printing the number of pages does not exist in this > > > > > > patch set. > > > > > > > > > > > > I have troubles the decipher your statement. > > > > > > > > > > > > You think that only if both the driver and KVM are *both* enabled, only then > > > > > > it makes sense to have this information available for sysadmin? > > > > > > > > > > Only if at least one of them is enabled. > > > > > > > > OK, thank you, that does make sense. > > > > > > > > What would happen if neither is enabled is that SGX_MemTotal would > > > > state that there is zero bytes of EPC. > > > > > > This is the problem I pointed out at the beginning, that (if I read code > > > correctly), it seems your current patch doesn't clear sgx_nr_all_pages when > > > neither is enabled (in sgx_init() in sgx/main.c). > > > > It's initialized to zero, so are you talking about fallback when something > > fails? > > > > /Jarkko > > Yes, shouldn't you have something similar to below? > > diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c > index 63d3de02bbcc..270f6103b6c0 100644 > --- a/arch/x86/kernel/cpu/sgx/main.c > +++ b/arch/x86/kernel/cpu/sgx/main.c > @@ -836,6 +836,7 @@ static int __init sgx_init(void) > vfree(sgx_epc_sections[i].pages); > memunmap(sgx_epc_sections[i].virt_addr); > } > + sgx_nr_all_pages = 0; > > return ret; > } Yeah, something along the lines. Thanks, this was really good remark. The fallback path is clearly broken. /Jarkko
