KVM: Retry fault before vmentry

When page is swapped in it is mapped into guest memory only after guest
tries to access it again and generate another fault. To save this fault
we can map it immediately since we know that guest is going to access
the page. Do it only when tdp is enabled for now. Shadow paging case is
more complicated. CR[034] and EFER registers should be switched before
doing mapping and then switched back.

Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index b5f4c1a36d65..c3076bcf5ef7 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -241,7 +241,7 @@ struct kvm_mmu {
         void (*new_cr3)(struct kvm_vcpu *vcpu);
         void (*set_cr3)(struct kvm_vcpu *vcpu, unsigned long root);
         unsigned long (*get_cr3)(struct kvm_vcpu *vcpu);
-        int (*page_fault)(struct kvm_vcpu *vcpu, gva_t gva, u32 err);
+        int (*page_fault)(struct kvm_vcpu *vcpu, gva_t gva, u32 err, bool no_apf);
         void (*inject_page_fault)(struct kvm_vcpu *vcpu);
         void (*free)(struct kvm_vcpu *vcpu);
         gpa_t (*gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t gva, u32 access,
@@ -815,6 +815,8 @@ void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu,
                                      struct kvm_async_pf *work);
 void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
                                  struct kvm_async_pf *work);
+void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu,
+                               struct kvm_async_pf *work);
 extern bool kvm_find_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn);
 
 #endif /* _ASM_X86_KVM_HOST_H */