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KVM: switch to get_user_pages_fast

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Convert gfn_to_pfn to use get_user_pages_fast, which can do lockless
pagetable lookups on x86. Kernel compilation on 4-way guest is 3.7%
faster on VMX.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Marcelo Tosatti
2008-09-16 20:54:47 -03:00
committed by Avi Kivity
parent 777b3f49d2
commit 4c2155ce81
6 changed files with 15 additions and 38 deletions
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6
arch/x86/kvm/x86.c
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@ -946,10 +946,8 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
/* ...but clean it before doing the actual write */
vcpu->arch.time_offset = data & ~(PAGE_MASK | 1);
down_read(&current->mm->mmap_sem);
vcpu->arch.time_page =
gfn_to_page(vcpu->kvm, data >> PAGE_SHIFT);
up_read(&current->mm->mmap_sem);
if (is_error_page(vcpu->arch.time_page)) {
kvm_release_page_clean(vcpu->arch.time_page);
@ -2322,9 +2320,7 @@ static int emulator_cmpxchg_emulated(unsigned long addr,
val = *(u64 *)new;
down_read(&current->mm->mmap_sem);
page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
up_read(&current->mm->mmap_sem);
kaddr = kmap_atomic(page, KM_USER0);
set_64bit((u64 *)(kaddr + offset_in_page(gpa)), val);
@ -3089,9 +3085,7 @@ static void vapic_enter(struct kvm_vcpu *vcpu)
if (!apic || !apic->vapic_addr)
return;
down_read(&current->mm->mmap_sem);
page = gfn_to_page(vcpu->kvm, apic->vapic_addr >> PAGE_SHIFT);
up_read(&current->mm->mmap_sem);
vcpu->arch.apic->vapic_page = page;
}