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Date: Wed, 07 Mar 2012 21:02:49 +0100
From: Davidlohr Bueso <dave@....org>
To: Avi Kivity <avi@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com>
Cc: lkml <linux-kernel@...r.kernel.org>, KVM <kvm@...r.kernel.org>
Subject: [PATCH] KVM: x86: add paging gcc optimization
From: Davidlohr Bueso <dave@....org>
Since most guests will have paging enabled for memory management, add likely() and unlikely()
optimizations around is_paging() checks.
Signed-off-by: Davidlohr Bueso <dave@....org>
---
arch/x86/kvm/mmu.c | 6 +++---
arch/x86/kvm/svm.c | 6 +++---
arch/x86/kvm/vmx.c | 16 ++++++++--------
arch/x86/kvm/x86.c | 8 ++++----
4 files changed, 18 insertions(+), 18 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 4cb1642..84f1e95 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3320,7 +3320,7 @@ static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
context->get_pdptr = kvm_pdptr_read;
context->inject_page_fault = kvm_inject_page_fault;
- if (!is_paging(vcpu)) {
+ if (unlikely(!is_paging(vcpu))) {
context->nx = false;
context->gva_to_gpa = nonpaging_gva_to_gpa;
context->root_level = 0;
@@ -3351,7 +3351,7 @@ int kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context)
ASSERT(vcpu);
ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
- if (!is_paging(vcpu))
+ if (unlikely(!is_paging(vcpu)))
r = nonpaging_init_context(vcpu, context);
else if (is_long_mode(vcpu))
r = paging64_init_context(vcpu, context);
@@ -3395,7 +3395,7 @@ static int init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
* arch.nested_mmu.gva_to_gpa function. Basically the gva_to_gpa
* functions between mmu and nested_mmu are swapped.
*/
- if (!is_paging(vcpu)) {
+ if (unlikely(!is_paging(vcpu))) {
g_context->nx = false;
g_context->root_level = 0;
g_context->gva_to_gpa = nonpaging_gva_to_gpa_nested;
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 53efd59..3887fca 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1555,12 +1555,12 @@ static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
#ifdef CONFIG_X86_64
if (vcpu->arch.efer & EFER_LME) {
- if (!is_paging(vcpu) && (cr0 & X86_CR0_PG)) {
+ if (unlikely(!is_paging(vcpu)) && (cr0 & X86_CR0_PG)) {
vcpu->arch.efer |= EFER_LMA;
svm->vmcb->save.efer |= EFER_LMA | EFER_LME;
}
- if (is_paging(vcpu) && !(cr0 & X86_CR0_PG)) {
+ if (likely(is_paging(vcpu)) && !(cr0 & X86_CR0_PG)) {
vcpu->arch.efer &= ~EFER_LMA;
svm->vmcb->save.efer &= ~(EFER_LMA | EFER_LME);
}
@@ -1991,7 +1991,7 @@ static void nested_svm_uninit_mmu_context(struct kvm_vcpu *vcpu)
static int nested_svm_check_permissions(struct vcpu_svm *svm)
{
if (!(svm->vcpu.arch.efer & EFER_SVME)
- || !is_paging(&svm->vcpu)) {
+ || unlikely(!is_paging(&svm->vcpu))) {
kvm_queue_exception(&svm->vcpu, UD_VECTOR);
return 1;
}
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 2c22fc7..f3144de 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2879,7 +2879,7 @@ static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu)
static void vmx_decache_cr3(struct kvm_vcpu *vcpu)
{
- if (enable_ept && is_paging(vcpu))
+ if (enable_ept && likely(is_paging(vcpu)))
vcpu->arch.cr3 = vmcs_readl(GUEST_CR3);
__set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail);
}
@@ -2898,7 +2898,7 @@ static void ept_load_pdptrs(struct kvm_vcpu *vcpu)
(unsigned long *)&vcpu->arch.regs_dirty))
return;
- if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) {
+ if (likely(is_paging(vcpu)) && is_pae(vcpu) && !is_long_mode(vcpu)) {
vmcs_write64(GUEST_PDPTR0, vcpu->arch.mmu.pdptrs[0]);
vmcs_write64(GUEST_PDPTR1, vcpu->arch.mmu.pdptrs[1]);
vmcs_write64(GUEST_PDPTR2, vcpu->arch.mmu.pdptrs[2]);
@@ -2908,7 +2908,7 @@ static void ept_load_pdptrs(struct kvm_vcpu *vcpu)
static void ept_save_pdptrs(struct kvm_vcpu *vcpu)
{
- if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) {
+ if (likely(is_paging(vcpu)) && is_pae(vcpu) && !is_long_mode(vcpu)) {
vcpu->arch.mmu.pdptrs[0] = vmcs_read64(GUEST_PDPTR0);
vcpu->arch.mmu.pdptrs[1] = vmcs_read64(GUEST_PDPTR1);
vcpu->arch.mmu.pdptrs[2] = vmcs_read64(GUEST_PDPTR2);
@@ -2937,7 +2937,7 @@ static void ept_update_paging_mode_cr0(unsigned long *hw_cr0,
CPU_BASED_CR3_STORE_EXITING));
vcpu->arch.cr0 = cr0;
vmx_set_cr4(vcpu, kvm_read_cr4(vcpu));
- } else if (!is_paging(vcpu)) {
+ } else if (unlikely(!is_paging(vcpu))) {
/* From nonpaging to paging */
vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
vmcs_read32(CPU_BASED_VM_EXEC_CONTROL) &
@@ -2970,9 +2970,9 @@ static void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
#ifdef CONFIG_X86_64
if (vcpu->arch.efer & EFER_LME) {
- if (!is_paging(vcpu) && (cr0 & X86_CR0_PG))
+ if (unlikely(!is_paging(vcpu)) && (cr0 & X86_CR0_PG))
enter_lmode(vcpu);
- if (is_paging(vcpu) && !(cr0 & X86_CR0_PG))
+ if (likely(is_paging(vcpu)) && !(cr0 & X86_CR0_PG))
exit_lmode(vcpu);
}
#endif
@@ -3010,7 +3010,7 @@ static void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
if (enable_ept) {
eptp = construct_eptp(cr3);
vmcs_write64(EPT_POINTER, eptp);
- guest_cr3 = is_paging(vcpu) ? kvm_read_cr3(vcpu) :
+ guest_cr3 = likely(is_paging(vcpu)) ? kvm_read_cr3(vcpu) :
vcpu->kvm->arch.ept_identity_map_addr;
ept_load_pdptrs(vcpu);
}
@@ -3038,7 +3038,7 @@ static int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
vcpu->arch.cr4 = cr4;
if (enable_ept) {
- if (!is_paging(vcpu)) {
+ if (unlikely(!is_paging(vcpu))) {
hw_cr4 &= ~X86_CR4_PAE;
hw_cr4 |= X86_CR4_PSE;
} else if (!(cr4 & X86_CR4_PAE)) {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7ce5878..84100d0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -510,7 +510,7 @@ int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
if ((cr0 & X86_CR0_PG) && !(cr0 & X86_CR0_PE))
return 1;
- if (!is_paging(vcpu) && (cr0 & X86_CR0_PG)) {
+ if (unlikely(!is_paging(vcpu)) && (cr0 & X86_CR0_PG)) {
#ifdef CONFIG_X86_64
if ((vcpu->arch.efer & EFER_LME)) {
int cs_db, cs_l;
@@ -597,7 +597,7 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
if (is_long_mode(vcpu)) {
if (!(cr4 & X86_CR4_PAE))
return 1;
- } else if (is_paging(vcpu) && (cr4 & X86_CR4_PAE)
+ } else if (likely(is_paging(vcpu)) && (cr4 & X86_CR4_PAE)
&& ((cr4 ^ old_cr4) & pdptr_bits)
&& !load_pdptrs(vcpu, vcpu->arch.walk_mmu,
kvm_read_cr3(vcpu)))
@@ -631,7 +631,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
if (is_pae(vcpu)) {
if (cr3 & CR3_PAE_RESERVED_BITS)
return 1;
- if (is_paging(vcpu) &&
+ if (likely(is_paging(vcpu)) &&
!load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))
return 1;
}
@@ -818,7 +818,7 @@ static int set_efer(struct kvm_vcpu *vcpu, u64 efer)
if (efer & efer_reserved_bits)
return 1;
- if (is_paging(vcpu)
+ if (likely(is_paging(vcpu))
&& (vcpu->arch.efer & EFER_LME) != (efer & EFER_LME))
return 1;
--
1.7.4.1
--
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