KVM: SVM: optimize nested vmrun

Only copy the necessary parts of the vmcb save area on vmrun and save
precious time.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 21 insertions, 7 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 2f5f2236f2a2..f11f88005c29 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1681,6 +1681,7 @@ static int nested_svm_vmrun(struct vcpu_svm *svm, void *arg1,
 {
         struct vmcb *nested_vmcb = (struct vmcb *)arg1;
         struct vmcb *hsave = svm->hsave;
+        struct vmcb *vmcb = svm->vmcb;
 
         /* nested_vmcb is our indicator if nested SVM is activated */
         svm->nested_vmcb = svm->vmcb->save.rax;
@@ -1691,12 +1692,25 @@ static int nested_svm_vmrun(struct vcpu_svm *svm, void *arg1,
 
         /* Save the old vmcb, so we don't need to pick what we save, but
            can restore everything when a VMEXIT occurs */
-        memcpy(hsave, svm->vmcb, sizeof(struct vmcb));
-        /* We need to remember the original CR3 in the SPT case */
-        if (!npt_enabled)
-                hsave->save.cr3 = svm->vcpu.arch.cr3;
-        hsave->save.cr4 = svm->vcpu.arch.cr4;
-        hsave->save.rip = svm->next_rip;
+        hsave->save.es     = vmcb->save.es;
+        hsave->save.cs     = vmcb->save.cs;
+        hsave->save.ss     = vmcb->save.ss;
+        hsave->save.ds     = vmcb->save.ds;
+        hsave->save.gdtr   = vmcb->save.gdtr;
+        hsave->save.idtr   = vmcb->save.idtr;
+        hsave->save.efer   = svm->vcpu.arch.shadow_efer;
+        hsave->save.cr0    = svm->vcpu.arch.cr0;
+        hsave->save.cr4    = svm->vcpu.arch.cr4;
+        hsave->save.rflags = vmcb->save.rflags;
+        hsave->save.rip    = svm->next_rip;
+        hsave->save.rsp    = vmcb->save.rsp;
+        hsave->save.rax    = vmcb->save.rax;
+        if (npt_enabled)
+                hsave->save.cr3    = vmcb->save.cr3;
+        else
+                hsave->save.cr3    = svm->vcpu.arch.cr3;
+
+        hsave->control = vmcb->control;
 
         if (svm->vmcb->save.rflags & X86_EFLAGS_IF)
                 svm->vcpu.arch.hflags |= HF_HIF_MASK;
@@ -1721,7 +1735,7 @@ static int nested_svm_vmrun(struct vcpu_svm *svm, void *arg1,
                 kvm_set_cr3(&svm->vcpu, nested_vmcb->save.cr3);
                 kvm_mmu_reset_context(&svm->vcpu);
         }
-        svm->vmcb->save.cr2 = nested_vmcb->save.cr2;
+        svm->vmcb->save.cr2 = svm->vcpu.arch.cr2 = nested_vmcb->save.cr2;
         kvm_register_write(&svm->vcpu, VCPU_REGS_RAX, nested_vmcb->save.rax);
         kvm_register_write(&svm->vcpu, VCPU_REGS_RSP, nested_vmcb->save.rsp);
         kvm_register_write(&svm->vcpu, VCPU_REGS_RIP, nested_vmcb->save.rip);