KVM: Remove unnecessary divide operations
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>
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@ -235,6 +235,7 @@ struct kvm_vm_data {
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#define KVM_REQ_PTC_G 32
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#define KVM_REQ_RESUME 33
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#define KVM_HPAGE_GFN_SHIFT(x) 0
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#define KVM_NR_PAGE_SIZES 1
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#define KVM_PAGES_PER_HPAGE(x) 1
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@ -35,6 +35,7 @@
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#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
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/* We don't currently support large pages. */
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#define KVM_HPAGE_GFN_SHIFT(x) 0
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#define KVM_NR_PAGE_SIZES 1
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#define KVM_PAGES_PER_HPAGE(x) (1UL<<31)
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@ -41,7 +41,8 @@ struct sca_block {
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} __attribute__((packed));
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#define KVM_NR_PAGE_SIZES 2
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#define KVM_HPAGE_SHIFT(x) (PAGE_SHIFT + ((x) - 1) * 8)
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#define KVM_HPAGE_GFN_SHIFT(x) (((x) - 1) * 8)
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#define KVM_HPAGE_SHIFT(x) (PAGE_SHIFT + KVM_HPAGE_GFN_SHIFT(x))
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#define KVM_HPAGE_SIZE(x) (1UL << KVM_HPAGE_SHIFT(x))
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#define KVM_HPAGE_MASK(x) (~(KVM_HPAGE_SIZE(x) - 1))
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#define KVM_PAGES_PER_HPAGE(x) (KVM_HPAGE_SIZE(x) / PAGE_SIZE)
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@ -44,7 +44,8 @@
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/* KVM Hugepage definitions for x86 */
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#define KVM_NR_PAGE_SIZES 3
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#define KVM_HPAGE_SHIFT(x) (PAGE_SHIFT + (((x) - 1) * 9))
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#define KVM_HPAGE_GFN_SHIFT(x) (((x) - 1) * 9)
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#define KVM_HPAGE_SHIFT(x) (PAGE_SHIFT + KVM_HPAGE_GFN_SHIFT(x))
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#define KVM_HPAGE_SIZE(x) (1UL << KVM_HPAGE_SHIFT(x))
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#define KVM_HPAGE_MASK(x) (~(KVM_HPAGE_SIZE(x) - 1))
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#define KVM_PAGES_PER_HPAGE(x) (KVM_HPAGE_SIZE(x) / PAGE_SIZE)
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@ -423,8 +423,8 @@ static int *slot_largepage_idx(gfn_t gfn,
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{
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unsigned long idx;
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idx = (gfn / KVM_PAGES_PER_HPAGE(level)) -
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(slot->base_gfn / KVM_PAGES_PER_HPAGE(level));
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idx = (gfn >> KVM_HPAGE_GFN_SHIFT(level)) -
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(slot->base_gfn >> KVM_HPAGE_GFN_SHIFT(level));
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return &slot->lpage_info[level - 2][idx].write_count;
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}
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@ -528,8 +528,8 @@ static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level)
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if (likely(level == PT_PAGE_TABLE_LEVEL))
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return &slot->rmap[gfn - slot->base_gfn];
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idx = (gfn / KVM_PAGES_PER_HPAGE(level)) -
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(slot->base_gfn / KVM_PAGES_PER_HPAGE(level));
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idx = (gfn >> KVM_HPAGE_GFN_SHIFT(level)) -
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(slot->base_gfn >> KVM_HPAGE_GFN_SHIFT(level));
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return &slot->lpage_info[level - 2][idx].rmap_pde;
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}
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@ -626,9 +626,9 @@ int __kvm_set_memory_region(struct kvm *kvm,
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if (new.lpage_info[i])
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continue;
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lpages = 1 + (base_gfn + npages - 1) /
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KVM_PAGES_PER_HPAGE(level);
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lpages -= base_gfn / KVM_PAGES_PER_HPAGE(level);
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lpages = 1 + ((base_gfn + npages - 1)
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>> KVM_HPAGE_GFN_SHIFT(level));
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lpages -= base_gfn >> KVM_HPAGE_GFN_SHIFT(level);
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new.lpage_info[i] = vmalloc(lpages * sizeof(*new.lpage_info[i]));
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@ -638,9 +638,9 @@ int __kvm_set_memory_region(struct kvm *kvm,
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memset(new.lpage_info[i], 0,
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lpages * sizeof(*new.lpage_info[i]));
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if (base_gfn % KVM_PAGES_PER_HPAGE(level))
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if (base_gfn & (KVM_PAGES_PER_HPAGE(level) - 1))
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new.lpage_info[i][0].write_count = 1;
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if ((base_gfn+npages) % KVM_PAGES_PER_HPAGE(level))
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if ((base_gfn+npages) & (KVM_PAGES_PER_HPAGE(level) - 1))
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new.lpage_info[i][lpages - 1].write_count = 1;
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ugfn = new.userspace_addr >> PAGE_SHIFT;
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/*
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