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KVM: Remove unnecessary divide operations

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This patch converts unnecessary divide and modulo operations
in the KVM large page related code into logical operations.
This allows to convert gfn_t to u64 while not breaking 32
bit builds.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Joerg Roedel
2010-07-01 16:00:11 +02:00
committed by Avi Kivity
parent 95c87e2b44
commit 828554136b
6 changed files with 15 additions and 11 deletions
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10
virt/kvm/kvm_main.c
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@@ -626,9 +626,9 @@ int __kvm_set_memory_region(struct kvm *kvm,
if (new.lpage_info[i])
continue;
lpages = 1 + (base_gfn + npages - 1) /
KVM_PAGES_PER_HPAGE(level);
lpages -= base_gfn / KVM_PAGES_PER_HPAGE(level);
lpages = 1 + ((base_gfn + npages - 1)
>> KVM_HPAGE_GFN_SHIFT(level));
lpages -= base_gfn >> KVM_HPAGE_GFN_SHIFT(level);
new.lpage_info[i] = vmalloc(lpages * sizeof(*new.lpage_info[i]));
@@ -638,9 +638,9 @@ int __kvm_set_memory_region(struct kvm *kvm,
memset(new.lpage_info[i], 0,
lpages * sizeof(*new.lpage_info[i]));
if (base_gfn % KVM_PAGES_PER_HPAGE(level))
if (base_gfn & (KVM_PAGES_PER_HPAGE(level) - 1))
new.lpage_info[i][0].write_count = 1;
if ((base_gfn+npages) % KVM_PAGES_PER_HPAGE(level))
if ((base_gfn+npages) & (KVM_PAGES_PER_HPAGE(level) - 1))
new.lpage_info[i][lpages - 1].write_count = 1;
ugfn = new.userspace_addr >> PAGE_SHIFT;
/*