diff mbox

[v5] kvm/fpu: Enable fully eager restore kvm FPU

Message ID 1352253671-1262-1-git-send-email-xudong.hao@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Hao, Xudong Nov. 7, 2012, 2:01 a.m. UTC
Romove fpu lazy restore logic, using eager restore totally.

v5 changes from v4:
- remove lazy fpu restore totally, fpu eager restore does not have performance
regression and simple the code.

v4 changes from v3:
- Wrap up some confused code with a clear function lazy_fpu_allowed()
- Update fpu while update cr4 too.

v3 changes from v2:
- Make fpu active explicitly while guest xsave is enabling and non-lazy xstate
bit exist.

v2 changes from v1:
- Expand KVM_XSTATE_LAZY to 64 bits before negating it.

Signed-off-by: Xudong Hao <xudong.hao@intel.com>
---
 arch/x86/kvm/vmx.c       | 9 ++-------
 arch/x86/kvm/x86.c       | 8 +-------
 include/linux/kvm_host.h | 1 -
 3 files changed, 3 insertions(+), 15 deletions(-)

Comments

Marcelo Tosatti Nov. 20, 2012, 10 p.m. UTC | #1
On Wed, Nov 07, 2012 at 10:01:11AM +0800, Xudong Hao wrote:
> Romove fpu lazy restore logic, using eager restore totally.
> 
> v5 changes from v4:
> - remove lazy fpu restore totally, fpu eager restore does not have performance
> regression and simple the code.
> 
> v4 changes from v3:
> - Wrap up some confused code with a clear function lazy_fpu_allowed()
> - Update fpu while update cr4 too.
> 
> v3 changes from v2:
> - Make fpu active explicitly while guest xsave is enabling and non-lazy xstate
> bit exist.
> 
> v2 changes from v1:
> - Expand KVM_XSTATE_LAZY to 64 bits before negating it.
> 
> Signed-off-by: Xudong Hao <xudong.hao@intel.com>
> ---
>  arch/x86/kvm/vmx.c       | 9 ++-------
>  arch/x86/kvm/x86.c       | 8 +-------
>  include/linux/kvm_host.h | 1 -
>  3 files changed, 3 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 6599e45..c1fd2e1 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -1197,7 +1197,7 @@ static void update_exception_bitmap(struct kvm_vcpu *vcpu)
>  	u32 eb;
>  
>  	eb = (1u << PF_VECTOR) | (1u << UD_VECTOR) | (1u << MC_VECTOR) |
> -	     (1u << NM_VECTOR) | (1u << DB_VECTOR);
> +	     (1u << DB_VECTOR);
>  	if ((vcpu->guest_debug &
>  	     (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP)) ==
>  	    (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP))

Please remove the code entirely, including:

        if (is_no_device(intr_info)) {
                vmx_fpu_activate(vcpu);
                return 1;
        }

and clts handling.

fpu_active/fpu_deactivate callbacks become unused, don't they?
Also remove fpu_active variable.

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Hao, Xudong Nov. 21, 2012, 3:30 a.m. UTC | #2
> -----Original Message-----
> From: Marcelo Tosatti [mailto:mtosatti@redhat.com]
> Sent: Wednesday, November 21, 2012 6:00 AM
> To: Hao, Xudong
> Cc: avi@redhat.com; kvm@vger.kernel.org
> Subject: Re: [PATCH v5] kvm/fpu: Enable fully eager restore kvm FPU
> 
> On Wed, Nov 07, 2012 at 10:01:11AM +0800, Xudong Hao wrote:
> > Romove fpu lazy restore logic, using eager restore totally.
> >
> > v5 changes from v4:
> > - remove lazy fpu restore totally, fpu eager restore does not have
> performance
> > regression and simple the code.
> >
> > v4 changes from v3:
> > - Wrap up some confused code with a clear function lazy_fpu_allowed()
> > - Update fpu while update cr4 too.
> >
> > v3 changes from v2:
> > - Make fpu active explicitly while guest xsave is enabling and non-lazy xstate
> > bit exist.
> >
> > v2 changes from v1:
> > - Expand KVM_XSTATE_LAZY to 64 bits before negating it.
> >
> > Signed-off-by: Xudong Hao <xudong.hao@intel.com>
> > ---
> >  arch/x86/kvm/vmx.c       | 9 ++-------
> >  arch/x86/kvm/x86.c       | 8 +-------
> >  include/linux/kvm_host.h | 1 -
> >  3 files changed, 3 insertions(+), 15 deletions(-)
> >
> > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> > index 6599e45..c1fd2e1 100644
> > --- a/arch/x86/kvm/vmx.c
> > +++ b/arch/x86/kvm/vmx.c
> > @@ -1197,7 +1197,7 @@ static void update_exception_bitmap(struct
> kvm_vcpu *vcpu)
> >  	u32 eb;
> >
> >  	eb = (1u << PF_VECTOR) | (1u << UD_VECTOR) | (1u << MC_VECTOR) |
> > -	     (1u << NM_VECTOR) | (1u << DB_VECTOR);
> > +	     (1u << DB_VECTOR);
> >  	if ((vcpu->guest_debug &
> >  	     (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP)) ==
> >  	    (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP))
> 
> Please remove the code entirely, including:
> 
>         if (is_no_device(intr_info)) {
>                 vmx_fpu_activate(vcpu);
>                 return 1;
>         }
> 
> and clts handling.
> 
> fpu_active/fpu_deactivate callbacks become unused, don't they?
> Also remove fpu_active variable.

Okay, will remove all of these.
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diff mbox

Patch

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 6599e45..c1fd2e1 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1197,7 +1197,7 @@  static void update_exception_bitmap(struct kvm_vcpu *vcpu)
 	u32 eb;
 
 	eb = (1u << PF_VECTOR) | (1u << UD_VECTOR) | (1u << MC_VECTOR) |
-	     (1u << NM_VECTOR) | (1u << DB_VECTOR);
+	     (1u << DB_VECTOR);
 	if ((vcpu->guest_debug &
 	     (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP)) ==
 	    (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP))
@@ -1206,8 +1206,6 @@  static void update_exception_bitmap(struct kvm_vcpu *vcpu)
 		eb = ~0;
 	if (enable_ept)
 		eb &= ~(1u << PF_VECTOR); /* bypass_guest_pf = 0 */
-	if (vcpu->fpu_active)
-		eb &= ~(1u << NM_VECTOR);
 
 	/* When we are running a nested L2 guest and L1 specified for it a
 	 * certain exception bitmap, we must trap the same exceptions and pass
@@ -3022,9 +3020,6 @@  static void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 	if (enable_ept)
 		ept_update_paging_mode_cr0(&hw_cr0, cr0, vcpu);
 
-	if (!vcpu->fpu_active)
-		hw_cr0 |= X86_CR0_TS | X86_CR0_MP;
-
 	vmcs_writel(CR0_READ_SHADOW, cr0);
 	vmcs_writel(GUEST_CR0, hw_cr0);
 	vcpu->arch.cr0 = cr0;
@@ -7119,7 +7114,7 @@  void load_vmcs12_host_state(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 	 * but we also need to update cr0_guest_host_mask and exception_bitmap.
 	 */
 	update_exception_bitmap(vcpu);
-	vcpu->arch.cr0_guest_owned_bits = (vcpu->fpu_active ? X86_CR0_TS : 0);
+	vcpu->arch.cr0_guest_owned_bits = X86_CR0_TS;
 	vmcs_writel(CR0_GUEST_HOST_MASK, ~vcpu->arch.cr0_guest_owned_bits);
 
 	/*
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 49fa1f0..cd5aafe 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5275,10 +5275,6 @@  static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 			r = 0;
 			goto out;
 		}
-		if (kvm_check_request(KVM_REQ_DEACTIVATE_FPU, vcpu)) {
-			vcpu->fpu_active = 0;
-			kvm_x86_ops->fpu_deactivate(vcpu);
-		}
 		if (kvm_check_request(KVM_REQ_APF_HALT, vcpu)) {
 			/* Page is swapped out. Do synthetic halt */
 			vcpu->arch.apf.halted = true;
@@ -5320,8 +5316,7 @@  static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	preempt_disable();
 
 	kvm_x86_ops->prepare_guest_switch(vcpu);
-	if (vcpu->fpu_active)
-		kvm_load_guest_fpu(vcpu);
+	kvm_load_guest_fpu(vcpu);
 	kvm_load_guest_xcr0(vcpu);
 
 	vcpu->mode = IN_GUEST_MODE;
@@ -6007,7 +6002,6 @@  void kvm_put_guest_fpu(struct kvm_vcpu *vcpu)
 	fpu_save_init(&vcpu->arch.guest_fpu);
 	__kernel_fpu_end();
 	++vcpu->stat.fpu_reload;
-	kvm_make_request(KVM_REQ_DEACTIVATE_FPU, vcpu);
 	trace_kvm_fpu(0);
 }
 
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 99a4762..0b33163 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -122,7 +122,6 @@  static inline bool is_error_page(struct page *page)
 #define KVM_REQ_MMU_SYNC           7
 #define KVM_REQ_CLOCK_UPDATE       8
 #define KVM_REQ_KICK               9
-#define KVM_REQ_DEACTIVATE_FPU    10
 #define KVM_REQ_EVENT             11
 #define KVM_REQ_APF_HALT          12
 #define KVM_REQ_STEAL_UPDATE      13