crash_clear_loaded_vmcss is added to VMCLEAR vmcss loaded on all
cpus. And when loading kvm_intel module, the function pointer will be
made valid.
The percpu variable vmclear_skipped is added to flag the case that
if loaded_vmcss_on_cpu list is being modified while the machine crashes
and doing kdump, the vmclear here can be skipped.
Signed-off-by: Zhang Yanfei <zhangyanfei at cn.fujitsu.com>
---
arch/x86/include/asm/kexec.h | 3 +++
arch/x86/kernel/crash.c | 32 ++++++++++++++++++++++++++++++++
2 files changed, 35 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 317ff17..d892211 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -163,6 +163,9 @@ struct kimage_arch {
};
#endif
+extern void (*crash_clear_loaded_vmcss)(void);
+DECLARE_PER_CPU(int, vmclear_skipped);
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_KEXEC_H */
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 13ad899..b9f264e 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -16,6 +16,7 @@
#include <linux/delay.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
+#include <linux/module.h>
#include <asm/processor.h>
#include <asm/hardirq.h>
@@ -30,6 +31,27 @@
int in_crash_kexec;
+/*
+ * This is used to VMCLEAR vmcss loaded on all
+ * cpus. And when loading kvm_intel module, the
+ * function pointer will be made valid.
+ */
+void (*crash_clear_loaded_vmcss)(void) = NULL;
+EXPORT_SYMBOL_GPL(crash_clear_loaded_vmcss);
+
+DEFINE_PER_CPU(int, vmclear_skipped) = 1;
+EXPORT_SYMBOL_GPL(vmclear_skipped);
+
+static void cpu_emergency_clear_loaded_vmcss(void)
+{
+ int cpu = raw_smp_processor_id();
+ int skipped;
+
+ skipped = per_cpu(vmclear_skipped, cpu);
+ if (!skipped && crash_clear_loaded_vmcss)
+ crash_clear_loaded_vmcss();
+}
+
#if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
@@ -46,6 +68,11 @@ static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
#endif
crash_save_cpu(regs, cpu);
+ /*
+ * VMCLEAR vmcss loaded on all cpus if needed.
+ */
+ cpu_emergency_clear_loaded_vmcss();
+
/* Disable VMX or SVM if needed.
*
* We need to disable virtualization on all CPUs.
@@ -88,6 +115,11 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
kdump_nmi_shootdown_cpus();
+ /*
+ * VMCLEAR vmcss loaded on this cpu if needed.
+ */
+ cpu_emergency_clear_loaded_vmcss();
+
/* Booting kdump kernel with VMX or SVM enabled won't work,
* because (among other limitations) we can't disable paging
* with the virt flags.
--
1.7.1
