From de88416d6141b745c4e22e1a9345d142642e036d Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 13 Jul 2018 16:23:18 +0200 Subject: [PATCH] x86/l1tf: Handle EPT disabled state proper commit a7b9020b06ec6d7c3f3b0d4ef1a9eba12654f4f7 upstream If Extended Page Tables (EPT) are disabled or not supported, no L1D flushing is required. The setup function can just avoid setting up the L1D flush for the EPT=n case. Invoke it after the hardware setup has be done and enable_ept has the correct state and expose the EPT disabled state in the mitigation status as well. Signed-off-by: Thomas Gleixner Tested-by: Jiri Kosina Reviewed-by: Greg Kroah-Hartman Reviewed-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20180713142322.612160168@linutronix.de Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/vmx.h | 1 + arch/x86/kernel/cpu/bugs.c | 9 ++++---- arch/x86/kvm/vmx.c | 44 ++++++++++++++++++++++---------------- 3 files changed, 32 insertions(+), 22 deletions(-) diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h index 6b9e556acef7..7b0492817169 100644 --- a/arch/x86/include/asm/vmx.h +++ b/arch/x86/include/asm/vmx.h @@ -576,6 +576,7 @@ enum vmx_l1d_flush_state { VMENTER_L1D_FLUSH_NEVER, VMENTER_L1D_FLUSH_COND, VMENTER_L1D_FLUSH_ALWAYS, + VMENTER_L1D_FLUSH_EPT_DISABLED, }; extern enum vmx_l1d_flush_state l1tf_vmx_mitigation; diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 511e6d63d9dd..b75828cf7715 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -676,10 +676,11 @@ static void __init l1tf_select_mitigation(void) #if IS_ENABLED(CONFIG_KVM_INTEL) static const char *l1tf_vmx_states[] = { - [VMENTER_L1D_FLUSH_AUTO] = "auto", - [VMENTER_L1D_FLUSH_NEVER] = "vulnerable", - [VMENTER_L1D_FLUSH_COND] = "conditional cache flushes", - [VMENTER_L1D_FLUSH_ALWAYS] = "cache flushes", + [VMENTER_L1D_FLUSH_AUTO] = "auto", + [VMENTER_L1D_FLUSH_NEVER] = "vulnerable", + [VMENTER_L1D_FLUSH_COND] = "conditional cache flushes", + [VMENTER_L1D_FLUSH_ALWAYS] = "cache flushes", + [VMENTER_L1D_FLUSH_EPT_DISABLED] = "EPT disabled", }; static ssize_t l1tf_show_state(char *buf) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index ba4ae2bc854f..8ddc6b794a94 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -12502,6 +12502,11 @@ static int __init vmx_setup_l1d_flush(void) if (!boot_cpu_has_bug(X86_BUG_L1TF)) return 0; + if (!enable_ept) { + l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_EPT_DISABLED; + return 0; + } + l1tf_vmx_mitigation = vmentry_l1d_flush; if (vmentry_l1d_flush == VMENTER_L1D_FLUSH_NEVER) @@ -12528,18 +12533,35 @@ static void vmx_cleanup_l1d_flush(void) l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO; } + +static void vmx_exit(void) +{ +#ifdef CONFIG_KEXEC_CORE + RCU_INIT_POINTER(crash_vmclear_loaded_vmcss, NULL); + synchronize_rcu(); +#endif + + kvm_exit(); + + vmx_cleanup_l1d_flush(); +} +module_exit(vmx_exit) + static int __init vmx_init(void) { int r; - r = vmx_setup_l1d_flush(); + r = kvm_init(&vmx_x86_ops, sizeof(struct vcpu_vmx), + __alignof__(struct vcpu_vmx), THIS_MODULE); if (r) return r; - r = kvm_init(&vmx_x86_ops, sizeof(struct vcpu_vmx), - __alignof__(struct vcpu_vmx), THIS_MODULE); + /* + * Must be called after kvm_init() so enable_ept is properly set up + */ + r = vmx_setup_l1d_flush(); if (r) { - vmx_cleanup_l1d_flush(); + vmx_exit(); return r; } @@ -12550,18 +12572,4 @@ static int __init vmx_init(void) return 0; } - -static void __exit vmx_exit(void) -{ -#ifdef CONFIG_KEXEC_CORE - RCU_INIT_POINTER(crash_vmclear_loaded_vmcss, NULL); - synchronize_rcu(); -#endif - - kvm_exit(); - - vmx_cleanup_l1d_flush(); -} - module_init(vmx_init) -module_exit(vmx_exit) -- 2.20.1