KVM: Cache pdptrs

Instead of reloading the pdptrs on every entry and exit (vmcs writes on vmx,
guest memory access on svm) extract them on demand.

Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 75e9df097845..2ad8c97f58cc 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -246,6 +246,10 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3)
         ret = 1;
 
         memcpy(vcpu->arch.pdptrs, pdpte, sizeof(vcpu->arch.pdptrs));
+        __set_bit(VCPU_EXREG_PDPTR,
+                  (unsigned long *)&vcpu->arch.regs_avail);
+        __set_bit(VCPU_EXREG_PDPTR,
+                  (unsigned long *)&vcpu->arch.regs_dirty);
 out:
 
         return ret;
@@ -261,6 +265,10 @@ static bool pdptrs_changed(struct kvm_vcpu *vcpu)
         if (is_long_mode(vcpu) || !is_pae(vcpu))
                 return false;
 
+        if (!test_bit(VCPU_EXREG_PDPTR,
+                      (unsigned long *)&vcpu->arch.regs_avail))
+                return true;
+
         r = kvm_read_guest(vcpu->kvm, vcpu->arch.cr3 & ~31u, pdpte, sizeof(pdpte));
         if (r < 0)
                 goto out;