Add warning when `nx_huge_pages` is enabled by kvm mmu for hint that huge pages may be splited by kernel. Signed-off-by: Li Yu <liyu.yukiteru@xxxxxxxxxxxxx> --- arch/x86/kvm/mmu/mmu.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 1a64ba5b9437..b75dbaf29f2d 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -6091,12 +6091,17 @@ static int set_nx_huge_pages(const char *val, const struct kernel_param *kp) return 0; } +#define ITLB_MULTIHIT_MSG "iTLB multi-hit CPU bug present and cpu mitigations enabled, huge pages may be splited by kernel for security. See CVE-2018-12207 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/multihit.html for details.\n" + int kvm_mmu_module_init(void) { int ret = -ENOMEM; - if (nx_huge_pages == -1) + if (nx_huge_pages == -1) { __set_nx_huge_pages(get_nx_auto_mode()); + if (is_nx_huge_page_enabled()) + pr_warn_once(ITLB_MULTIHIT_MSG); + } /* * MMU roles use union aliasing which is, generally speaking, an -- 2.11.0
