x86: adds paravirt hook for swapgs
This patch adds paravirt hook for swapgs operation, which is a privileged
operation in x86_64.
Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/asm-x86/paravirt.h b/include/asm-x86/paravirt.h
index 7d1c126..e8fbf74 100644
--- a/include/asm-x86/paravirt.h
+++ b/include/asm-x86/paravirt.h
@@ -127,6 +127,8 @@
void (*irq_enable_syscall_ret)(void);
void (*iret)(void);
+ void (*swapgs)(void);
+
struct pv_lazy_ops lazy_mode;
};
@@ -1228,6 +1230,13 @@
call *pv_cpu_ops+PV_CPU_read_cr0; \
pop %edx; pop %ecx
#else
+#define SWAPGS \
+ PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_swapgs), CLBR_NONE, \
+ PV_SAVE_REGS; \
+ call *pv_cpu_ops+PV_CPU_swapgs; \
+ PV_RESTORE_REGS \
+ )
+
#define GET_CR2_INTO_RCX \
call *pv_mmu_ops+PV_MMU_read_cr2; \
movq %rax, %rcx; \
diff --git a/include/asm-x86/processor.h b/include/asm-x86/processor.h
index e6fa06f..72740c6 100644
--- a/include/asm-x86/processor.h
+++ b/include/asm-x86/processor.h
@@ -435,6 +435,13 @@
#endif
}
+static inline void native_swapgs(void)
+{
+#ifdef CONFIG_X86_64
+ asm volatile("swapgs" ::: "memory");
+#endif
+}
+
#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#else
@@ -456,6 +463,7 @@
}
#define set_iopl_mask native_set_iopl_mask
+#define SWAPGS swapgs
#endif /* CONFIG_PARAVIRT */
/*
