On Wed, 2021-09-29 at 09:22 +0200, Greg Kroah-Hartman wrote: > On Tue, Sep 28, 2021 at 09:20:41PM +0300, Jarkko Sakkinen wrote: > > On Tue, 2021-09-28 at 06:54 +0200, Greg Kroah-Hartman wrote: > > > On Tue, Sep 28, 2021 at 06:13:50AM +0300, Jarkko Sakkinen wrote: > > > > The amount of SGX memory on the system is determined by the BIOS and it > > > > varies wildly between systems. It can be from dozens of MB's on desktops > > > > or VM's, up to many GB's on servers. Just like for regular memory, it is > > > > sometimes useful to know the amount of usable SGX memory in the system. > > > > > > > > Add an attribute for the amount of SGX memory in bytes to each NUMA > > > > node. The path is /sys/devices/system/node/node[0-9]*/sgx/memory_size. > > > > Calculate these values by summing up EPC section sizes for each node > > > > during the driver initalization. > > > > > > > > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > > > Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx> > > > > --- > > > > > > > > v6: > > > > * Initialize node->size to zero in sgx_setup_epc_section(), when the > > > > node is first accessed. The bug report: > > > > https://lore.kernel.org/linux-sgx/f45245ba-41b8-62ae-38b5-64725a214bad@xxxxxxxxx/ > > > > > > > > v5: > > > > * A new patch based on the discussion on > > > > https://lore.kernel.org/linux-sgx/3a7cab4115b4f902f3509ad8652e616b91703e1d.camel@xxxxxxxxxx/T/#t > > > > > > > > Documentation/x86/sgx.rst | 14 ++++++ > > > > > > sysfs files have to be documented in Documentation/ABI/ so that they can > > > be automatically checked, and added to the documentation output > > > properly. Please do that here as well. > > > > Right, I'll document it to sysfs-devices-node. > > > > > > arch/x86/kernel/cpu/sgx/main.c | 91 ++++++++++++++++++++++++++++++++++ > > > > arch/x86/kernel/cpu/sgx/sgx.h | 2 + > > > > 3 files changed, 107 insertions(+) > > > > > > > > diff --git a/Documentation/x86/sgx.rst b/Documentation/x86/sgx.rst > > > > index dd0ac96ff9ef..f9d9cfa6dbf9 100644 > > > > --- a/Documentation/x86/sgx.rst > > > > +++ b/Documentation/x86/sgx.rst > > > > @@ -250,3 +250,17 @@ user wants to deploy SGX applications both on the host and in guests > > > > on the same machine, the user should reserve enough EPC (by taking out > > > > total virtual EPC size of all SGX VMs from the physical EPC size) for > > > > host SGX applications so they can run with acceptable performance. > > > > + > > > > +Per NUMA node SGX attributes > > > > +============================ > > > > + > > > > +NUMA nodes devices expose SGX specific attributes in the following path: > > > > + > > > > + /sys/devices/system/node/node[0-9]*/sgx/ > > > > + > > > > +Attributes > > > > +---------- > > > > + > > > > +memory_size > > > > + Total available physical SGX memory, also known as Enclave > > > > + Page Cache (EPC), in bytes. > > > > diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c > > > > index a6e313f1a82d..4f1e3b5e3d14 100644 > > > > --- a/arch/x86/kernel/cpu/sgx/main.c > > > > +++ b/arch/x86/kernel/cpu/sgx/main.c > > > > @@ -714,9 +714,11 @@ static bool __init sgx_page_cache_init(void) > > > > spin_lock_init(&sgx_numa_nodes[nid].lock); > > > > INIT_LIST_HEAD(&sgx_numa_nodes[nid].free_page_list); > > > > node_set(nid, sgx_numa_mask); > > > > + sgx_numa_nodes[nid].size = 0; > > > > } > > > > > > > > sgx_epc_sections[i].node = &sgx_numa_nodes[nid]; > > > > + sgx_numa_nodes[nid].size += size; > > > > > > > > sgx_nr_epc_sections++; > > > > } > > > > @@ -790,6 +792,87 @@ int sgx_set_attribute(unsigned long *allowed_attributes, > > > > } > > > > EXPORT_SYMBOL_GPL(sgx_set_attribute); > > > > > > > > +#ifdef CONFIG_NUMA > > > > +static void sgx_numa_exit(void) > > > > +{ > > > > + int nid; > > > > + > > > > + for (nid = 0; nid < num_possible_nodes(); nid++) { > > > > + if (!sgx_numa_nodes[nid].kobj) > > > > + continue; > > > > + > > > > + kobject_put(sgx_numa_nodes[nid].kobj); > > > > + } > > > > +} > > > > + > > > > +#define SGX_NODE_ATTR_RO(_name) \ > > > > + static struct kobj_attribute _name##_attr = __ATTR_RO(_name) > > > > > > Why are you dealing with a "raw" kobject? Shouldn't you have a device > > > and use a device attribute? > > > > > > > +static bool sgx_numa_init(void) > > > > +{ > > > > + struct sgx_numa_node *node; > > > > + struct device *dev; > > > > + int nid; > > > > + int ret; > > > > + > > > > + for (nid = 0; nid < num_possible_nodes(); nid++) { > > > > + if (!sgx_numa_nodes[nid].size) > > > > + continue; > > > > + > > > > + node = &sgx_numa_nodes[nid]; > > > > + dev = &node_devices[nid]->dev; > > > > + > > > > + node->kobj = kobject_create_and_add("sgx", &dev->kobj); > > > > > > You just "broke" the tree by putting a raw kobject below a struct > > > device. Please do not do that. > > > > I looked how hugetlb was implemented as a starting point, since it is > > existing mainline code, i.e. in mm/hugetlb.c: > > > > - hugetlb_register_node() > > - hugetlb_register_all_nodes() > > - HSTATE_ATTR_RO() > > > > hugetlb code attaches raw kobjects to the node device, by using this > > (perhaps anti)pattern. > > Never look at the memory code for how to use sysfs "properly" :) > > It deals with raw kobjects as it is not tied into the driver model at > all. You are, so do not try to route around it, userspace will not be > happy with you if you do so. > > > > > + if (!node->kobj) { > > > > + sgx_numa_exit(); > > > > + return false; > > > > + } > > > > + > > > > + ret = sysfs_create_group(node->kobj, &sgx_node_attr_group); > > > > > > And you raced with userspace and lost. > > > > > > Wait, you have a kobject _just_ for a subdirectory name? Why? Use a > > > named attribute group, that's exactly what that is for. > > > > > > Properly attach your attributes to the device you have, don't do extra > > > work and complex code that you do not have to at all. > > > > Here the reference was hugetlb_sysfs_init() and hugetlb_sysfs_add_hstate(). > > Agreed, that a named group would make a lot more sense. > > Again, ignore all sysfs code for the memory subsystem please :) OK, cool, thank you. I can do that. > > thanks, > > greg k-h /Jarkko
