This patch provides an alternative way to clear vmcss related to guests
on all cpus when doing kdump.
Signed-off-by: zhangyanfei <zhangyanfei at cn.fujitsu.com>
---
arch/x86/include/asm/kexec.h | 3 +++
arch/x86/kernel/crash.c | 23 +++++++++++++++++++++++
2 files changed, 26 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 317ff17..0692921 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -163,6 +163,9 @@ struct kimage_arch {
};
#endif
+extern int clear_loaded_vmcs_enabled;
+extern void (*crash_clear_loaded_vmcss)(void);
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_KEXEC_H */
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 13ad899..947550e 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 +31,24 @@
int in_crash_kexec;
+/*
+ * If clear_loaded_vmcs_enabled is set, vmcss
+ * that are loaded on all cpus will be cleared
+ * via crash_clear_loaded_vmcss.
+ */
+int clear_loaded_vmcs_enabled;
+void (*crash_clear_loaded_vmcss)(void) = NULL;
+EXPORT_SYMBOL_GPL(crash_clear_loaded_vmcss);
+
+static void cpu_emergency_clear_loaded_vmcss(void)
+{
+ if (clear_loaded_vmcs_enabled &&
+ crash_clear_loaded_vmcss &&
+ cpu_has_vmx() && cpu_vmx_enabled()) {
+ 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 +65,8 @@ static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
#endif
crash_save_cpu(regs, cpu);
+ cpu_emergency_clear_loaded_vmcss();
+
/* Disable VMX or SVM if needed.
*
* We need to disable virtualization on all CPUs.
@@ -88,6 +109,8 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
kdump_nmi_shootdown_cpus();
+ 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
