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

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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.

Cc: Jim Mattson <jmattson@google.com>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2020-04-16 09:48:07 -04:00
parent c583eed6d7
commit c36b71503a
3 changed files with 10 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
arch/x86/kvm/mmu/mmu.c
View File

@ -4082,19 +4082,16 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
gpa_t cr2_or_gpa, kvm_pfn_t *pfn, bool write, gpa_t cr2_or_gpa, kvm_pfn_t *pfn, bool write,
bool *writable) bool *writable)
{ {
struct kvm_memory_slot *slot; struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
bool async; bool async;
/* /* Don't expose private memslots to L2. */
* Don't expose private memslots to L2. if (is_guest_mode(vcpu) && !kvm_is_visible_memslot(slot)) {
*/
if (is_guest_mode(vcpu) && !kvm_is_visible_gfn(vcpu->kvm, gfn)) {
*pfn = KVM_PFN_NOSLOT; *pfn = KVM_PFN_NOSLOT;
*writable = false; *writable = false;
return false; return false;
} }
slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
async = false; async = false;
*pfn = __gfn_to_pfn_memslot(slot, gfn, false, &async, write, writable); *pfn = __gfn_to_pfn_memslot(slot, gfn, false, &async, write, writable);
if (!async) if (!async)

6
include/linux/kvm_host.h
View File

@ -1357,6 +1357,12 @@ static inline void kvm_vcpu_set_dy_eligible(struct kvm_vcpu *vcpu, bool val)
} }
#endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */ #endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */
static inline bool kvm_is_visible_memslot(struct kvm_memory_slot *memslot)
{
return (memslot && memslot->id < KVM_USER_MEM_SLOTS &&
!(memslot->flags & KVM_MEMSLOT_INVALID));
}
struct kvm_vcpu *kvm_get_running_vcpu(void); struct kvm_vcpu *kvm_get_running_vcpu(void);
struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void); struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void);

6
virt/kvm/kvm_main.c
View File

@ -1607,11 +1607,7 @@ bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
{ {
struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn); struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn);
if (!memslot || memslot->id >= KVM_USER_MEM_SLOTS || return kvm_is_visible_memslot(memslot);
memslot->flags & KVM_MEMSLOT_INVALID)
return false;
return true;
} }
EXPORT_SYMBOL_GPL(kvm_is_visible_gfn); EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);