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x86/l1tf: Handle EPT disabled state proper

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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 <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20180713142322.612160168@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Thomas Gleixner 2018-07-13 16:23:18 +02:00 committed by Greg Kroah-Hartman
parent de6749ddf3
commit de88416d61
3 changed files with 39 additions and 29 deletions
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1
arch/x86/include/asm/vmx.h
View File

@ -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;

9
arch/x86/kernel/cpu/bugs.c
View File

@ -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)

58
arch/x86/kvm/vmx.c
View File

@ -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)
@ -12528,30 +12533,8 @@ static void vmx_cleanup_l1d_flush(void)
l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO;
}
static int __init vmx_init(void)
{
int r;
r = vmx_setup_l1d_flush();
if (r)
return r;
r = kvm_init(&vmx_x86_ops, sizeof(struct vcpu_vmx),
__alignof__(struct vcpu_vmx), THIS_MODULE);
if (r) {
vmx_cleanup_l1d_flush();
return r;
}
#ifdef CONFIG_KEXEC_CORE
rcu_assign_pointer(crash_vmclear_loaded_vmcss,
crash_vmclear_local_loaded_vmcss);
#endif
return 0;
}
static void __exit vmx_exit(void)
static void vmx_exit(void)
{
#ifdef CONFIG_KEXEC_CORE
RCU_INIT_POINTER(crash_vmclear_loaded_vmcss, NULL);
@ -12562,6 +12545,31 @@ static void __exit vmx_exit(void)
vmx_cleanup_l1d_flush();
}
module_init(vmx_init)
module_exit(vmx_exit)
static int __init vmx_init(void)
{
int r;
r = kvm_init(&vmx_x86_ops, sizeof(struct vcpu_vmx),
__alignof__(struct vcpu_vmx), THIS_MODULE);
if (r)
return r;
/*
* Must be called after kvm_init() so enable_ept is properly set up
*/
r = vmx_setup_l1d_flush();
if (r) {
vmx_exit();
return r;
}
#ifdef CONFIG_KEXEC_CORE
rcu_assign_pointer(crash_vmclear_loaded_vmcss,
crash_vmclear_local_loaded_vmcss);
#endif
return 0;
}
module_init(vmx_init)