On 2021-08-18 15:25, 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 SGX_MemTotal field to /proc/meminfo, which shows the total amount of
> usable SGX memory in the system. E.g. with 32 MB reserved for SGX from
> BIOS, the printout would be:
>
> SGX_MemTotal: 22528 kB
>
> It is less than 32 MB because some of the space is reserved for Enclave
> Page Cache Metadata (EPCM), which contains state variables for all the
> pages in the Enclave Page Cache (EPC). The latter contains the pages,
> which applications can use to create enclaves.
>
> Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> ---
> Documentation/x86/sgx.rst | 6 ++++++
> arch/x86/include/asm/sgx.h | 10 +++++++---
> arch/x86/kernel/cpu/sgx/main.c | 7 ++++++-
> arch/x86/mm/pat/set_memory.c | 5 +++++
> 4 files changed, 24 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/x86/sgx.rst b/Documentation/x86/sgx.rst
> index dd0ac96ff9ef..68ee171e1d8f 100644
> --- a/Documentation/x86/sgx.rst
> +++ b/Documentation/x86/sgx.rst
> @@ -250,3 +250,9 @@ 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.
> +
> +Supplemental fields for /proc/meminfo
> +=====================================
> +
> +SGX_MemTotal
> + The total usable SGX protected memory in kilobytes.
> diff --git a/arch/x86/include/asm/sgx.h b/arch/x86/include/asm/sgx.h
> index 05f3e21f01a7..2ae9dc8c9411 100644
> --- a/arch/x86/include/asm/sgx.h
> +++ b/arch/x86/include/asm/sgx.h
> @@ -365,6 +365,13 @@ struct sgx_sigstruct {
> * comment!
> */
>
> +#if defined(CONFIG_X86_SGX) || defined(CONFIG_X86_SGX_KVM)
> +extern unsigned long sgx_nr_all_pages;
> +
> +int sgx_set_attribute(unsigned long *allowed_attributes,
> + unsigned int attribute_fd);
> +#endif
> +
> #ifdef CONFIG_X86_SGX_KVM
> int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs,
> int *trapnr);
> @@ -372,7 +379,4 @@ int sgx_virt_einit(void __user *sigstruct, void __user *token,
> void __user *secs, u64 *lepubkeyhash, int *trapnr);
> #endif
>
> -int sgx_set_attribute(unsigned long *allowed_attributes,
> - unsigned int attribute_fd);
> -
This change seems unrelated?
> #endif /* _ASM_X86_SGX_H */
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index 63d3de02bbcc..1fe26a8e80dc 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -28,7 +28,10 @@ static DECLARE_WAIT_QUEUE_HEAD(ksgxd_waitq);
> static LIST_HEAD(sgx_active_page_list);
> static DEFINE_SPINLOCK(sgx_reclaimer_lock);
>
> -/* 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;
> +
> return true;
> }
>
> diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
> index ad8a5c586a35..82bb09c298de 100644
> --- a/arch/x86/mm/pat/set_memory.c
> +++ b/arch/x86/mm/pat/set_memory.c
> @@ -29,6 +29,7 @@
> #include <asm/proto.h>
> #include <asm/memtype.h>
> #include <asm/set_memory.h>
> +#include <asm/sgx.h>
>
> #include "../mm_internal.h"
>
> @@ -116,6 +117,10 @@ void arch_report_meminfo(struct seq_file *m)
> if (direct_gbpages)
> seq_printf(m, "DirectMap1G: %8lu kB\n",
> direct_pages_count[PG_LEVEL_1G] << 20);
> +
> +#if defined(CONFIG_X86_SGX) || defined(CONFIG_X86_SGX_KVM)
> + seq_printf(m, "SGX_MemTotal: %8lu kB\n", sgx_nr_all_pages << 2);
> +#endif
> }
> #else
> static inline void split_page_count(int level) { }
>
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