diff options
| author | Avi Kivity <avi@redhat.com> | 2010-12-21 12:54:20 +0200 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2011-01-12 11:31:09 +0200 |
| commit | 110312c84b5fbd4daf5de2417fa8ab5ec883858d (patch) | |
| tree | 704d8c4925d2ba236a0e6e97ee0733339210bce5 /arch | |
| parent | 07c116d2f53d721377fe428d067e2cecf80c906e (diff) | |
| download | linux-110312c84b5fbd4daf5de2417fa8ab5ec883858d.tar.bz2 | |
KVM: VMX: Optimize atomic EFER load
When NX is enabled on the host but not on the guest, we use the entry/exit
msr load facility, which is slow. Optimize it to use entry/exit efer load,
which is ~1200 cycles faster.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/vmx.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 736f83955ce9..a713c69bfcee 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -191,6 +191,8 @@ static unsigned long *vmx_io_bitmap_b; static unsigned long *vmx_msr_bitmap_legacy; static unsigned long *vmx_msr_bitmap_longmode; +static bool cpu_has_load_ia32_efer; + static DECLARE_BITMAP(vmx_vpid_bitmap, VMX_NR_VPIDS); static DEFINE_SPINLOCK(vmx_vpid_lock); @@ -664,6 +666,12 @@ static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr) unsigned i; struct msr_autoload *m = &vmx->msr_autoload; + if (msr == MSR_EFER && cpu_has_load_ia32_efer) { + vmcs_clear_bits(VM_ENTRY_CONTROLS, VM_ENTRY_LOAD_IA32_EFER); + vmcs_clear_bits(VM_EXIT_CONTROLS, VM_EXIT_LOAD_IA32_EFER); + return; + } + for (i = 0; i < m->nr; ++i) if (m->guest[i].index == msr) break; @@ -683,6 +691,14 @@ static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr, unsigned i; struct msr_autoload *m = &vmx->msr_autoload; + if (msr == MSR_EFER && cpu_has_load_ia32_efer) { + vmcs_write64(GUEST_IA32_EFER, guest_val); + vmcs_write64(HOST_IA32_EFER, host_val); + vmcs_set_bits(VM_ENTRY_CONTROLS, VM_ENTRY_LOAD_IA32_EFER); + vmcs_set_bits(VM_EXIT_CONTROLS, VM_EXIT_LOAD_IA32_EFER); + return; + } + for (i = 0; i < m->nr; ++i) if (m->guest[i].index == msr) break; @@ -1418,6 +1434,14 @@ static __init int adjust_vmx_controls(u32 ctl_min, u32 ctl_opt, return 0; } +static __init bool allow_1_setting(u32 msr, u32 ctl) +{ + u32 vmx_msr_low, vmx_msr_high; + + rdmsr(msr, vmx_msr_low, vmx_msr_high); + return vmx_msr_high & ctl; +} + static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf) { u32 vmx_msr_low, vmx_msr_high; @@ -1532,6 +1556,12 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf) vmcs_conf->vmexit_ctrl = _vmexit_control; vmcs_conf->vmentry_ctrl = _vmentry_control; + cpu_has_load_ia32_efer = + allow_1_setting(MSR_IA32_VMX_ENTRY_CTLS, + VM_ENTRY_LOAD_IA32_EFER) + && allow_1_setting(MSR_IA32_VMX_EXIT_CTLS, + VM_EXIT_LOAD_IA32_EFER); + return 0; } |