From e2a81baf6604a2e08e10c7405b0349106f77c8af Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Mon, 17 Mar 2008 16:37:17 -0700 Subject: 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 Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/xen/setup.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'arch/x86/xen/setup.c') diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 2341492bf7a0..82517e4a752a 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -16,6 +16,7 @@ #include #include +#include #include #include @@ -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) -- cgit v1.2.3