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authorJeremy Fitzhardinge <jeremy@goop.org>2008-03-17 16:37:17 -0700
committerIngo Molnar <mingo@elte.hu>2008-04-24 23:57:31 +0200
commite2a81baf6604a2e08e10c7405b0349106f77c8af (patch)
tree3eaf386316be1f499d92fae213493ec3d6b5b576 /arch/x86/xen/setup.c
parentaa380c82b83252754a8c11bfc92359bd87cbf710 (diff)
xen: support sysenter/sysexit if hypervisor does
64-bit Xen supports sysenter for 32-bit guests, so support its use. (sysenter is faster than int $0x80 in 32-on-64.) sysexit is still not supported, so we fake it up using iret. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/xen/setup.c')
-rw-r--r--arch/x86/xen/setup.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 2341492bf7a..82517e4a752 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -16,6 +16,7 @@
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
+#include <xen/interface/callback.h>
#include <xen/interface/physdev.h>
#include <xen/features.h>
@@ -68,6 +69,24 @@ static void __init fiddle_vdso(void)
*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
}
+void xen_enable_sysenter(void)
+{
+ int cpu = smp_processor_id();
+ extern void xen_sysenter_target(void);
+ /* Mask events on entry, even though they get enabled immediately */
+ static struct callback_register sysenter = {
+ .type = CALLBACKTYPE_sysenter,
+ .address = { __KERNEL_CS, (unsigned long)xen_sysenter_target },
+ .flags = CALLBACKF_mask_events,
+ };
+
+ if (!boot_cpu_has(X86_FEATURE_SEP) ||
+ HYPERVISOR_callback_op(CALLBACKOP_register, &sysenter) != 0) {
+ clear_cpu_cap(&cpu_data(cpu), X86_FEATURE_SEP);
+ clear_cpu_cap(&boot_cpu_data, X86_FEATURE_SEP);
+ }
+}
+
void __init xen_arch_setup(void)
{
struct physdev_set_iopl set_iopl;
@@ -82,6 +101,8 @@ void __init xen_arch_setup(void)
HYPERVISOR_set_callbacks(__KERNEL_CS, (unsigned long)xen_hypervisor_callback,
__KERNEL_CS, (unsigned long)xen_failsafe_callback);
+ xen_enable_sysenter();
+
set_iopl.iopl = 1;
rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
if (rc != 0)