From: Jarkko Sakkinen jarkko@kernel.org

mainline inclusion from mainline-v5.11-rc1 commit 38853a303982e3be3eccb1a1132399a5c5e2d806 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I4SIGI CVE: NA

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Add a kernel parameter to disable SGX kernel support and document it.

[ bp: Massage. ]

Intel-SIG: commit 38853a303982 x86/cpu/intel: Add a nosgx kernel parameter Backport for SGX Foundations support

Signed-off-by: Jarkko Sakkinen jarkko@kernel.org Signed-off-by: Borislav Petkov bp@suse.de Reviewed-by: Sean Christopherson sean.j.christopherson@intel.com Acked-by: Jethro Beekman jethro@fortanix.com Tested-by: Sean Christopherson sean.j.christopherson@intel.com Link: https://lkml.kernel.org/r/20201112220135.165028-9-jarkko@kernel.org Signed-off-by: Fan Du fan.du@intel.com #openEuler_contributor Signed-off-by: Laibin Qiu qiulaibin@huawei.com Reviewed-by: Bamvor Zhang bamvor.zhang@suse.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- Documentation/admin-guide/kernel-parameters.txt | 2 ++ arch/x86/kernel/cpu/feat_ctl.c | 9 +++++++++ 2 files changed, 11 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index b73108a82f18..a4e5614bee12 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3498,6 +3498,8 @@

nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.

+ nosgx [X86-64,SGX] Disables Intel SGX kernel support. + nosmp [SMP] Tells an SMP kernel to act as a UP kernel, and disable the IO APIC. legacy for "maxcpus=0".

diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c index d38e97325018..3b1b01f2b248 100644 --- a/arch/x86/kernel/cpu/feat_ctl.c +++ b/arch/x86/kernel/cpu/feat_ctl.c @@ -99,6 +99,15 @@ static void clear_sgx_caps(void) setup_clear_cpu_cap(X86_FEATURE_SGX_LC); }

+static int __init nosgx(char *str) +{ + clear_sgx_caps(); + + return 0; +} + +early_param("nosgx", nosgx); + void init_ia32_feat_ctl(struct cpuinfo_x86 *c) { bool tboot = tboot_enabled();