On 8/18/21 7:40 AM, Jarkko Sakkinen wrote:
On Wed, Aug 18, 2021 at 03:29:59PM +0200, Jethro Beekman wrote:
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?
It's just a good practice not to define symbols that do not exist, so that
if the symbol is ever used, we get a compilation error, not linking error.
Since this is included to set_memory.c, based on this conclusion, I added
the check.
It would make sense to make this change in a separate patch since.
thanks,
-- Shuah
