Paolo,
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On Sat, Sep 22, 2018 at 09:56:38AM +0800, Wei Yang wrote:
>KVM_PAGES_PER_HPAGE is got by left shift (KVM_HPAGE_GFN_SHIFT + PAGE_SHIFT)
>and then divide by PAGE_SIZE, which could be simplified by just left shift
>KVM_HPAGE_GFN_SHIFT.
>
>At the same time, in almost 40% places where KVM_PAGES_PER_HPAGE is used,
>pfn mask is actually what it needs instead of the number of pages.
>
>This patch replaces KVM_PAGES_PER_HPAGE with KVM_HPAGE_GFN_SIZE and
>introduces KVM_HPAGE_GFN_MASK to make it a little bit easy to read.
>
>Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
>---
> arch/x86/include/asm/kvm_host.h | 3 ++-
> arch/x86/kvm/mmu.c | 10 +++++-----
> arch/x86/kvm/paging_tmpl.h | 6 +++---
> arch/x86/kvm/x86.c | 6 +++---
> 4 files changed, 13 insertions(+), 12 deletions(-)
>
>diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
>index f1a4e520ef5c..c5e7bb811b1e 100644
>--- a/arch/x86/include/asm/kvm_host.h
>+++ b/arch/x86/include/asm/kvm_host.h
>@@ -104,10 +104,11 @@
> /* KVM Hugepage definitions for x86 */
> #define KVM_NR_PAGE_SIZES 3
> #define KVM_HPAGE_GFN_SHIFT(x) (((x) - 1) * 9)
>+#define KVM_HPAGE_GFN_SIZE(x) (1UL << KVM_HPAGE_GFN_SHIFT(x))
>+#define KVM_HPAGE_GFN_MASK(x) (~(KVM_HPAGE_GFN_SIZE(x) - 1))
> #define KVM_HPAGE_SHIFT(x) (PAGE_SHIFT + KVM_HPAGE_GFN_SHIFT(x))
> #define KVM_HPAGE_SIZE(x) (1UL << KVM_HPAGE_SHIFT(x))
> #define KVM_HPAGE_MASK(x) (~(KVM_HPAGE_SIZE(x) - 1))
>-#define KVM_PAGES_PER_HPAGE(x) (KVM_HPAGE_SIZE(x) / PAGE_SIZE)
>
> static inline gfn_t gfn_to_index(gfn_t gfn, gfn_t base_gfn, int level)
> {
>diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
>index 0caaaa25e88b..897614414311 100644
>--- a/arch/x86/kvm/mmu.c
>+++ b/arch/x86/kvm/mmu.c
>@@ -3170,7 +3170,7 @@ static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
> * head.
> */
> *levelp = level = PT_DIRECTORY_LEVEL;
>- mask = KVM_PAGES_PER_HPAGE(level) - 1;
>+ mask = KVM_HPAGE_GFN_SIZE(level) - 1;
> VM_BUG_ON((gfn & mask) != (pfn & mask));
> if (pfn & mask) {
> gfn &= ~mask;
>@@ -3416,7 +3416,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
> if (level > PT_DIRECTORY_LEVEL)
> level = PT_DIRECTORY_LEVEL;
>
>- gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
>+ gfn &= KVM_HPAGE_GFN_MASK(level);
> }
>
> if (fast_page_fault(vcpu, v, level, error_code))
>@@ -4018,9 +4018,9 @@ EXPORT_SYMBOL_GPL(kvm_handle_page_fault);
> static bool
> check_hugepage_cache_consistency(struct kvm_vcpu *vcpu, gfn_t gfn, int level)
> {
>- int page_num = KVM_PAGES_PER_HPAGE(level);
>+ int page_num = KVM_HPAGE_GFN_SIZE(level);
>
>- gfn &= ~(page_num - 1);
>+ gfn &= KVM_HPAGE_GFN_MASK(level);
>
> return kvm_mtrr_check_gfn_range_consistency(vcpu, gfn, page_num);
> }
>@@ -4053,7 +4053,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
> if (level > PT_DIRECTORY_LEVEL &&
> !check_hugepage_cache_consistency(vcpu, gfn, level))
> level = PT_DIRECTORY_LEVEL;
>- gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
>+ gfn &= KVM_HPAGE_GFN_MASK(level);
> }
>
> if (fast_page_fault(vcpu, gpa, level, error_code))
>diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
>index 14ffd973df54..c8a242715cbb 100644
>--- a/arch/x86/kvm/paging_tmpl.h
>+++ b/arch/x86/kvm/paging_tmpl.h
>@@ -658,7 +658,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
> if (is_shadow_present_pte(*it.sptep))
> continue;
>
>- direct_gfn = gw->gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
>+ direct_gfn = gw->gfn & KVM_HPAGE_GFN_MASK(it.level);
>
> sp = kvm_mmu_get_page(vcpu, direct_gfn, addr, it.level-1,
> true, direct_access);
>@@ -700,7 +700,7 @@ FNAME(is_self_change_mapping)(struct kvm_vcpu *vcpu,
> bool *write_fault_to_shadow_pgtable)
> {
> int level;
>- gfn_t mask = ~(KVM_PAGES_PER_HPAGE(walker->level) - 1);
>+ gfn_t mask = KVM_HPAGE_GFN_MASK(walker->level);
> bool self_changed = false;
>
> if (!(walker->pte_access & ACC_WRITE_MASK ||
>@@ -786,7 +786,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
> level = mapping_level(vcpu, walker.gfn, &force_pt_level);
> if (likely(!force_pt_level)) {
> level = min(walker.level, level);
>- walker.gfn = walker.gfn & ~(KVM_PAGES_PER_HPAGE(level) - 1);
>+ walker.gfn = walker.gfn & KVM_HPAGE_GFN_MASK(level);
> }
> } else
> force_pt_level = true;
>diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>index f7dff0457846..70b4e5e74f7d 100644
>--- a/arch/x86/kvm/x86.c
>+++ b/arch/x86/kvm/x86.c
>@@ -9021,9 +9021,9 @@ int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot,
>
> slot->arch.lpage_info[i - 1] = linfo;
>
>- if (slot->base_gfn & (KVM_PAGES_PER_HPAGE(level) - 1))
>+ if (slot->base_gfn & (KVM_HPAGE_GFN_SIZE(level) - 1))
> linfo[0].disallow_lpage = 1;
>- if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1))
>+ if ((slot->base_gfn + npages) & (KVM_HPAGE_GFN_SIZE(level) - 1))
> linfo[lpages - 1].disallow_lpage = 1;
> ugfn = slot->userspace_addr >> PAGE_SHIFT;
> /*
>@@ -9031,7 +9031,7 @@ int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot,
> * other, or if explicitly asked to, disable large page
> * support for this slot
> */
>- if ((slot->base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE(level) - 1) ||
>+ if ((slot->base_gfn ^ ugfn) & (KVM_HPAGE_GFN_SIZE(level) - 1) ||
> !kvm_largepages_enabled()) {
> unsigned long j;
>
>--
>2.15.1
--
Wei Yang
Help you, Help me
