[PATCH 09/15] adds paravirt hook for swapgs

Glauber de Oliveira Costa
2007-12-20T20:11:51Z

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>
---
arch/x86/kernel/paravirt.c | 1 +
include/asm-x86/paravirt.h | 9 +++++++++
include/asm-x86/processor.h | 8 ++++++++
3 files changed, 18 insertions(+), 0 deletions(-)

Index: linux-2.6-x86/arch/x86/kernel/paravirt.c
===================================================================
--- linux-2.6-x86.orig/arch/x86/kernel/paravirt.c 2007-12-20 19:07:22.000000000 -0800
+++ linux-2.6-x86/arch/x86/kernel/paravirt.c 2007-12-20 19:08:06.000000000 -0800
@@ -390,6 +390,7 @@

.irq_enable_syscall_ret = native_irq_enable_syscall_ret,
.iret = native_iret,
+ .swapgs = native_swapgs,

.set_iopl_mask = native_set_iopl_mask,
.io_delay = native_io_delay,
Index: linux-2.6-x86/include/asm-x86/paravirt.h
===================================================================
--- linux-2.6-x86.orig/include/asm-x86/paravirt.h 2007-12-20 19:07:29.000000000 -0800
+++ linux-2.6-x86/include/asm-x86/paravirt.h 2007-12-20 19:08:06.000000000 -0800
@@ -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; \
Index: linux-2.6-x86/include/asm-x86/processor.h
===================================================================
--- linux-2.6-x86.orig/include/asm-x86/processor.h 2007-12-20 19:06:59.000000000 -0800
+++ linux-2.6-x86/include/asm-x86/processor.h 2007-12-20 19:08:06.000000000 -0800
@@ -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 */

/*