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KVM: x86/mmu: Avoid an extra memslot lookup in try_async_pf() for L2

Create a new function kvm_is_visible_memslot() and use it from kvm_is_visible_gfn(); use the new function in try_async_pf() too, to avoid an extra memslot lookup. Opportunistically squish a multi-line comment into a single-line comment. Note, the end result, KVM_PFN_NOSLOT, is unchanged.

Paolo Bonzini committed 6 years ago

Commit c36b7151 parent c583eed3 files · +10 −11Browse files

Unified · Split

3 files
  1. arch/x86/kvm/mmu/mmu.c +3 −6
  2. include/linux/kvm_host.h +6 −0
  3. virt/kvm/kvm_main.c +1 −5
arch/x86/kvm/mmu/mmu.c+3−6
@@ -4082,19 +4082,16 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn, · 4081 unmodified lines
4082 gpa_t cr2_or_gpa, kvm_pfn_t *pfn, bool write,4082 gpa_t cr2_or_gpa, kvm_pfn_t *pfn, bool write,
4083 bool *writable)4083 bool *writable)
4084{4084{
4085 struct kvm_memory_slot *slot;4085 struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
4086 bool async;4086 bool async;
4087 4087
4088 /*4088 /* Don't expose private memslots to L2. */
4089 * Don't expose private memslots to L2.4089 if (is_guest_mode(vcpu) && !kvm_is_visible_memslot(slot)) {
4090 */
4091 if (is_guest_mode(vcpu) && !kvm_is_visible_gfn(vcpu->kvm, gfn)) {
4092 *pfn = KVM_PFN_NOSLOT;4090 *pfn = KVM_PFN_NOSLOT;
4093 *writable = false;4091 *writable = false;
4094 return false;4092 return false;
4095 }4093 }
4096 4094
4097 slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
4098 async = false;4095 async = false;
4099 *pfn = __gfn_to_pfn_memslot(slot, gfn, false, &async, write, writable);4096 *pfn = __gfn_to_pfn_memslot(slot, gfn, false, &async, write, writable);
4100 if (!async)4097 if (!async)
include/linux/kvm_host.h+6−0
@@ -1357,6 +1357,12 @@ static inline void kvm_vcpu_set_dy_eligible(struct kvm_vcpu *vcpu, bool val) · 1356 unmodified lines
1357}1357}
1358#endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */1358#endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */
1359 1359
1360static inline bool kvm_is_visible_memslot(struct kvm_memory_slot *memslot)
1361{
1362 return (memslot && memslot->id < KVM_USER_MEM_SLOTS &&
1363 !(memslot->flags & KVM_MEMSLOT_INVALID));
1364}
1365
1360struct kvm_vcpu *kvm_get_running_vcpu(void);1366struct kvm_vcpu *kvm_get_running_vcpu(void);
1361struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void);1367struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void);
1362 1368
virt/kvm/kvm_main.c+1−5
@@ -1607,11 +1607,7 @@ bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn) · 1606 unmodified lines
1607{1607{
1608 struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn);1608 struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn);
1609 1609
1610 if (!memslot || memslot->id >= KVM_USER_MEM_SLOTS ||1610 return kvm_is_visible_memslot(memslot);
1611 memslot->flags & KVM_MEMSLOT_INVALID)
1612 return false;
1613
1614 return true;
1615}1611}
1616EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);1612EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
1617 1613

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