On Fri, 2018-06-08 at 19:09 +0200, Jarkko Sakkinen wrote: > SGX has a set of data structures to maintain information about the enclaves > and their security properties. BIOS reserves a fixed size region of > physical memory for these structures by setting Processor Reserved Memory > Range Registers (PRMRR). This memory area is called Enclave Page Cache > (EPC). > > This commit implements the basic routines to allocate and free pages from > different EPC banks. There is also a swapper thread ksgxswapd for EPC pages > that gets woken up by sgx_alloc_page() when we run below the low watermark. > The swapper thread continues swapping pages up until it reaches the high > watermark. > > Each subsystem that uses SGX must provide a set of callbacks for EPC > pages that are used to reclaim, block and write an EPC page. Kernel > takes the responsibility of maintaining LRU cache for them. > > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx> > --- > arch/x86/include/asm/sgx.h | 67 +++++ > arch/x86/include/asm/sgx_arch.h | 224 ++++++++++++++++ > arch/x86/kernel/cpu/intel_sgx.c | 443 +++++++++++++++++++++++++++++++- > 3 files changed, 732 insertions(+), 2 deletions(-) > create mode 100644 arch/x86/include/asm/sgx_arch.h ... > diff --git a/arch/x86/kernel/cpu/intel_sgx.c b/arch/x86/kernel/cpu/intel_sgx.c > index db6b315334f4..ae2b5c5b455f 100644 > --- a/arch/x86/kernel/cpu/intel_sgx.c > +++ b/arch/x86/kernel/cpu/intel_sgx.c > @@ -14,14 +14,439 @@ > #include <linux/freezer.h> > #include <linux/highmem.h> > #include <linux/kthread.h> > +#include <linux/pagemap.h> > #include <linux/ratelimit.h> > #include <linux/sched/signal.h> > +#include <linux/shmem_fs.h> > #include <linux/slab.h> > > +#define SGX_NR_TO_SCAN 16 > +#define SGX_NR_LOW_PAGES 32 > +#define SGX_NR_HIGH_PAGES 64 > + > bool sgx_enabled __ro_after_init = false; > EXPORT_SYMBOL(sgx_enabled); > +bool sgx_lc_enabled __ro_after_init; > +EXPORT_SYMBOL(sgx_lc_enabled); > +atomic_t sgx_nr_free_pages = ATOMIC_INIT(0); > +EXPORT_SYMBOL(sgx_nr_free_pages); > +struct sgx_epc_bank sgx_epc_banks[SGX_MAX_EPC_BANKS]; > +EXPORT_SYMBOL(sgx_epc_banks); > +int sgx_nr_epc_banks; > +EXPORT_SYMBOL(sgx_nr_epc_banks); > +LIST_HEAD(sgx_active_page_list); > +EXPORT_SYMBOL(sgx_active_page_list); > +DEFINE_SPINLOCK(sgx_active_page_list_lock); > +EXPORT_SYMBOL(sgx_active_page_list_lock); I don't think we should be exporting anything other than sgx_enabled and sgx_lc_enabled. The only external use of a symbol that can't be trivially (re)moved is in the driver's sgx_pm_suspend() in sgx_main.c, which uses the sgx_active_page_list to invalidate enclaves. And that behavior seems unsafe, e.g. an enclave could theoretically have zero pages on the active list and so could be missed in the suspend flow. > +static struct task_struct *ksgxswapd_tsk; > +static DECLARE_WAIT_QUEUE_HEAD(ksgxswapd_waitq);
