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| author | Sheng Yang <sheng@linux.intel.com> | 2010-05-17 17:08:27 +0800 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2010-08-01 10:35:48 +0300 |
| commit | 7cf30855e02be7a207ffebb8b9350986f2ba83e9 (patch) | |
| tree | 114f0f2dfbe425bfb7736ebbeb1655c23d636db4 | |
| parent | 5ee481da7b62a992b91f958bf26aaaa92354c170 (diff) | |
| download | linux-stable-7cf30855e02be7a207ffebb8b9350986f2ba83e9.tar.gz linux-stable-7cf30855e02be7a207ffebb8b9350986f2ba83e9.tar.bz2 linux-stable-7cf30855e02be7a207ffebb8b9350986f2ba83e9.zip | |
KVM: x86: Use unlazy_fpu() for host FPU
We can avoid unnecessary fpu load when userspace process
didn't use FPU frequently.
Derived from Avi's idea.
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 1 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 18 |
2 files changed, 2 insertions, 17 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 0c06148fa3b1..d93601c52902 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -301,7 +301,6 @@ struct kvm_vcpu_arch { unsigned long mmu_seq; } update_pte; - struct i387_fxsave_struct host_fx_image; struct i387_fxsave_struct guest_fx_image; gva_t mmio_fault_cr2; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4c2096f30d90..54ce77582eda 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -52,6 +52,7 @@ #include <asm/desc.h> #include <asm/mtrr.h> #include <asm/mce.h> +#include <asm/i387.h> #define MAX_IO_MSRS 256 #define CR0_RESERVED_BITS \ @@ -5134,21 +5135,10 @@ void fx_init(struct kvm_vcpu *vcpu) { unsigned after_mxcsr_mask; - /* - * Touch the fpu the first time in non atomic context as if - * this is the first fpu instruction the exception handler - * will fire before the instruction returns and it'll have to - * allocate ram with GFP_KERNEL. - */ - if (!used_math()) - kvm_fx_save(&vcpu->arch.host_fx_image); - /* Initialize guest FPU by resetting ours and saving into guest's */ preempt_disable(); - kvm_fx_save(&vcpu->arch.host_fx_image); kvm_fx_finit(); kvm_fx_save(&vcpu->arch.guest_fx_image); - kvm_fx_restore(&vcpu->arch.host_fx_image); preempt_enable(); vcpu->arch.cr0 |= X86_CR0_ET; @@ -5165,7 +5155,7 @@ void kvm_load_guest_fpu(struct kvm_vcpu *vcpu) return; vcpu->guest_fpu_loaded = 1; - kvm_fx_save(&vcpu->arch.host_fx_image); + unlazy_fpu(current); kvm_fx_restore(&vcpu->arch.guest_fx_image); trace_kvm_fpu(1); } @@ -5177,7 +5167,6 @@ void kvm_put_guest_fpu(struct kvm_vcpu *vcpu) vcpu->guest_fpu_loaded = 0; kvm_fx_save(&vcpu->arch.guest_fx_image); - kvm_fx_restore(&vcpu->arch.host_fx_image); ++vcpu->stat.fpu_reload; set_bit(KVM_REQ_DEACTIVATE_FPU, &vcpu->requests); trace_kvm_fpu(0); @@ -5203,9 +5192,6 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu) { int r; - /* We do fxsave: this must be aligned. */ - BUG_ON((unsigned long)&vcpu->arch.host_fx_image & 0xF); - vcpu->arch.mtrr_state.have_fixed = 1; vcpu_load(vcpu); r = kvm_arch_vcpu_reset(vcpu); |