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SubjectRe: [PATCH v13 2/2] x86/sgx: Add an attribute for the amount of SGX memory in a NUMA node
On Tue, Nov 16, 2021 at 06:21:16PM +0200, 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.
>
> Introduce CONFIG_HAVE_ARCH_NODE_DEV_GROUP opt-in flag to expose an arch
> specific attribute group, and add an attribute for the amount of SGX
> memory in bytes to each NUMA node:
>
> /sys/devices/system/node/nodeX/x86/sgx_total_bytes
>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> ---
> v13:
> * Rebased on top of tip/x86/sgx.
>
> v12:
> * Device ID is set to same as NUMA node ID. Use that to get the correct
> NUMA node ID in sgx_total_bytes_show().
>
> v11:
> * Fix documentation and the commit message.
>
> v10:
> * Change DEVICE_ATTR_RO() to static (Greg K-H)
> * Change the attribute name as sgx_total_bytes, and attribute group
> name as "x86" (Dave).
> * Add a new config flag HAVE_ARCH_NODE_DEV_GROUP to identify, whether
> an arch exports arch specific attribute group for NUMA nodes.
>
> v9:
> * Fix racy initialization of sysfs attributes:
> https://lore.kernel.org/linux-sgx/YXOsx8SvFJV5R7lU@kroah.com/
>
> v8:
> * Fix a bug in sgx_numa_init(): node->dev should be only set after
> sysfe_create_group(). Otherwise, sysfs_remove_group() will issue a
> warning in sgx_numa_exit(), when sgx_create_group() is unsuccessful,
> because the group does not exist.
>
> v7:
> * Shorten memory_size to size. The prefix makes the name only longer
> but does not clarify things more than "size" would.
> * Use device_attribute instead of kobj_attribute.
> * Use named attribute group instead of creating raw kobject just for
> the "sgx" subdirectory.
>
> v6:
> * Initialize node->size to zero in sgx_setup_epc_section(), when the
> node is first accessed.
>
> v5
> * A new patch based on the discussion on
> https://lore.kernel.org/linux-sgx/3a7cab4115b4f902f3509ad8652e616b91703e1d.camel@kernel.org/T/#t
> ---
> Documentation/ABI/stable/sysfs-devices-node | 6 ++++++
> arch/Kconfig | 4 ++++
> arch/x86/Kconfig | 1 +
> arch/x86/kernel/cpu/sgx/main.c | 20 ++++++++++++++++++++
> arch/x86/kernel/cpu/sgx/sgx.h | 1 +
> drivers/base/node.c | 3 +++
> include/linux/numa.h | 4 ++++
> 7 files changed, 39 insertions(+)
>
> diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node
> index 484fc04bcc25..8db67aa472f1 100644
> --- a/Documentation/ABI/stable/sysfs-devices-node
> +++ b/Documentation/ABI/stable/sysfs-devices-node
> @@ -176,3 +176,9 @@ Contact: Keith Busch <keith.busch@intel.com>
> Description:
> The cache write policy: 0 for write-back, 1 for write-through,
> other or unknown.
> +
> +What: /sys/devices/system/node/nodeX/x86/sgx_total_bytes
> +Date: November 2021
> +Contact: Jarkko Sakkinen <jarkko@kernel.org>
> +Description:
> + The total amount of SGX physical memory in bytes.
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 26b8ed11639d..0a9dadb00b61 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -1302,6 +1302,10 @@ config ARCH_HAS_PARANOID_L1D_FLUSH
> config DYNAMIC_SIGFRAME
> bool
>
> +# Select, if arch has a named attribute group bound to NUMA device nodes.
> +config HAVE_ARCH_NODE_DEV_GROUP
> + bool
> +
> source "kernel/gcov/Kconfig"
>
> source "scripts/gcc-plugins/Kconfig"
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index b9281fab4e3e..f2b699d12eb8 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -269,6 +269,7 @@ config X86
> select HAVE_ARCH_KCSAN if X86_64
> select X86_FEATURE_NAMES if PROC_FS
> select PROC_PID_ARCH_STATUS if PROC_FS
> + select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX
> imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
>
> config INSTRUCTION_DECODER
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index b8e1703eecae..00af6f90d31a 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -825,9 +825,11 @@ static bool __init sgx_page_cache_init(void)
> INIT_LIST_HEAD(&sgx_numa_nodes[nid].free_page_list);
> INIT_LIST_HEAD(&sgx_numa_nodes[nid].sgx_poison_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++;
> }
> @@ -901,6 +903,24 @@ int sgx_set_attribute(unsigned long *allowed_attributes,
> }
> EXPORT_SYMBOL_GPL(sgx_set_attribute);
>
> +#ifdef CONFIG_NUMA
> +static ssize_t sgx_total_bytes_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> + return sysfs_emit(buf, "%lu\n", sgx_numa_nodes[dev->id].size);
> +}
> +static DEVICE_ATTR_RO(sgx_total_bytes);
> +
> +static struct attribute *arch_node_dev_attrs[] = {
> + &dev_attr_sgx_total_bytes.attr,
> + NULL,
> +};
> +
> +const struct attribute_group arch_node_dev_group = {
> + .name = "x86",
> + .attrs = arch_node_dev_attrs,
> +};
> +#endif /* CONFIG_NUMA */
> +
> static int __init sgx_init(void)
> {
> int ret;
> diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
> index 9ec3136c7800..0f17def9fe6f 100644
> --- a/arch/x86/kernel/cpu/sgx/sgx.h
> +++ b/arch/x86/kernel/cpu/sgx/sgx.h
> @@ -44,6 +44,7 @@ struct sgx_epc_page {
> struct sgx_numa_node {
> struct list_head free_page_list;
> struct list_head sgx_poison_page_list;
> + unsigned long size;
> spinlock_t lock;
> };
>
> diff --git a/drivers/base/node.c b/drivers/base/node.c
> index b5a4ba18f9f9..87acc47e8951 100644
> --- a/drivers/base/node.c
> +++ b/drivers/base/node.c
> @@ -581,6 +581,9 @@ static const struct attribute_group node_dev_group = {
>
> static const struct attribute_group *node_dev_groups[] = {
> &node_dev_group,
> +#ifdef CONFIG_HAVE_ARCH_NODE_DEV_GROUP
> + &arch_node_dev_group,
> +#endif
> NULL
> };
>
> diff --git a/include/linux/numa.h b/include/linux/numa.h
> index cb44cfe2b725..59df211d051f 100644
> --- a/include/linux/numa.h
> +++ b/include/linux/numa.h
> @@ -58,4 +58,8 @@ static inline int phys_to_target_node(u64 start)
> }
> #endif
>
> +#ifdef CONFIG_HAVE_ARCH_NODE_DEV_GROUP
> +extern const struct attribute_group arch_node_dev_group;
> +#endif
> +
> #endif /* _LINUX_NUMA_H */
> --
> 2.32.0
>

So what still needs to be done to this?

/Jarkko

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