diff options
| author |   Vitaly Kuznetsov <vkuznets@redhat.com> | 2018-03-13 18:48:05 +0100 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2018-03-16 22:03:54 +0100 |
| commit | 35060ed6a1ffc92106904f5e4b5823ca4facfc73 (patch) | |
| tree | 8bb681a4e0b7c15fd173e0c27aba1bd2460856ec /arch/x86/kernel/cpu | |
| parent | x86/kvm/vmx: read MSR_{FS,KERNEL_GS}_BASE from current->thread (diff) | |
x86/kvm/vmx: avoid expensive rdmsr for MSR_GS_BASE
vmx_save_host_state() is only called from kvm_arch_vcpu_ioctl_run() so
the context is pretty well defined and as we're past 'swapgs' MSR_GS_BASE
should contain kernel's GS base which we point to irq_stack_union.
Add new kernelmode_gs_base() API, irq_stack_union needs to be exported
as KVM can be build as module.
Acked-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kernel/cpu')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 348cf4821240..4702fbd98f92 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -487,7 +487,7 @@ void load_percpu_segment(int cpu) loadsegment(fs, __KERNEL_PERCPU); #else __loadsegment_simple(gs, 0); - wrmsrl(MSR_GS_BASE, (unsigned long)per_cpu(irq_stack_union.gs_base, cpu)); + wrmsrl(MSR_GS_BASE, cpu_kernelmode_gs_base(cpu)); #endif load_stack_canary_segment(); } @@ -1398,6 +1398,7 @@ __setup("clearcpuid=", setup_clearcpuid); #ifdef CONFIG_X86_64 DEFINE_PER_CPU_FIRST(union irq_stack_union, irq_stack_union) __aligned(PAGE_SIZE) __visible; +EXPORT_PER_CPU_SYMBOL_GPL(irq_stack_union); /* * The following percpu variables are hot. Align current_task to |