On Fri, Jan 07, 2022 at 10:16:15AM -0800, Kristen Carlson Accardi wrote: > SGX currently allows EPC pages to be overcommitted. If the system is > out of enclave memory, EPC pages are swapped to normal RAM via > a per enclave shared memory area. This shared memory is not charged > to the enclave or the task mapping it, making it hard to account > for using normal methods. Since SGX will allow EPC pages to be > overcommitted without limits, enclaves can consume system memory > for these backing pages without limits. > > In order to prevent this, set a cap on the amount of overcommit SGX > allows. Whenever a backing page is requested by an enclave, track > the total amount of shared memory pages used across all enclaves and > return an error if the overcommit limit has been reached. This will > restrict the total amount of backing pages that all enclaves can > consume to a maximum amount, and prevent enclaves from consuming > all the system RAM for backing pages. > > The overcommit percentage has a value of 150, which limits shared > memory page consumption to 1.5x the number of EPC pages in the system. > > Changes from v1 > ---------------- > * removed module parameter and disable boolean > * increased over commit percentage to 150% from 100% > > Kristen Carlson Accardi (2): > x86/sgx: Add accounting for tracking overcommit > x86/sgx: account backing pages > > arch/x86/kernel/cpu/sgx/encl.c | 76 ++++++++++++++++++++++++++++++++-- > arch/x86/kernel/cpu/sgx/encl.h | 6 ++- > arch/x86/kernel/cpu/sgx/main.c | 52 +++++++++++++++++++++-- > arch/x86/kernel/cpu/sgx/sgx.h | 2 + > 4 files changed, 128 insertions(+), 8 deletions(-) > > -- > 2.20.1 > I've tested also these. Looking at the feedback, there's nothing game changing, so you could add for the next version: Tested-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx> /Jarkko
