KVM: SVM: cache nested intercepts

When the nested intercepts are cached we don't need to call
get_user_pages and/or map the nested vmcb on every nested #vmexit to
check who will handle the intercept.
Further this patch aligns the emulated svm behavior better to real
hardware.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 23 insertions, 7 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index fbadaa7cb27a..4426c631057b 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -80,6 +80,15 @@ struct nested_state {
 
         /* gpa pointers to the real vectors */
         u64 vmcb_msrpm;
+
+        /* cache for intercepts of the guest */
+        u16 intercept_cr_read;
+        u16 intercept_cr_write;
+        u16 intercept_dr_read;
+        u16 intercept_dr_write;
+        u32 intercept_exceptions;
+        u64 intercept;
+
 };
 
 struct vcpu_svm {
@@ -1452,7 +1461,6 @@ static int nested_svm_exit_handled_real(struct vcpu_svm *svm,
                                         void *arg2,
                                         void *opaque)
 {
-        struct vmcb *nested_vmcb = (struct vmcb *)arg1;
         bool kvm_overrides = *(bool *)opaque;
         u32 exit_code = svm->vmcb->control.exit_code;
 
@@ -1479,38 +1487,38 @@ static int nested_svm_exit_handled_real(struct vcpu_svm *svm,
         switch (exit_code) {
         case SVM_EXIT_READ_CR0 ... SVM_EXIT_READ_CR8: {
                 u32 cr_bits = 1 << (exit_code - SVM_EXIT_READ_CR0);
-                if (nested_vmcb->control.intercept_cr_read & cr_bits)
+                if (svm->nested.intercept_cr_read & cr_bits)
                         return 1;
                 break;
         }
         case SVM_EXIT_WRITE_CR0 ... SVM_EXIT_WRITE_CR8: {
                 u32 cr_bits = 1 << (exit_code - SVM_EXIT_WRITE_CR0);
-                if (nested_vmcb->control.intercept_cr_write & cr_bits)
+                if (svm->nested.intercept_cr_write & cr_bits)
                         return 1;
                 break;
         }
         case SVM_EXIT_READ_DR0 ... SVM_EXIT_READ_DR7: {
                 u32 dr_bits = 1 << (exit_code - SVM_EXIT_READ_DR0);
-                if (nested_vmcb->control.intercept_dr_read & dr_bits)
+                if (svm->nested.intercept_dr_read & dr_bits)
                         return 1;
                 break;
         }
         case SVM_EXIT_WRITE_DR0 ... SVM_EXIT_WRITE_DR7: {
                 u32 dr_bits = 1 << (exit_code - SVM_EXIT_WRITE_DR0);
-                if (nested_vmcb->control.intercept_dr_write & dr_bits)
+                if (svm->nested.intercept_dr_write & dr_bits)
                         return 1;
                 break;
         }
         case SVM_EXIT_EXCP_BASE ... SVM_EXIT_EXCP_BASE + 0x1f: {
                 u32 excp_bits = 1 << (exit_code - SVM_EXIT_EXCP_BASE);
-                if (nested_vmcb->control.intercept_exceptions & excp_bits)
+                if (svm->nested.intercept_exceptions & excp_bits)
                         return 1;
                 break;
         }
         default: {
                 u64 exit_bits = 1ULL << (exit_code - SVM_EXIT_INTR);
                 nsvm_printk("exit code: 0x%x\n", exit_code);
-                if (nested_vmcb->control.intercept & exit_bits)
+                if (svm->nested.intercept & exit_bits)
                         return 1;
         }
         }
@@ -1801,6 +1809,14 @@ static int nested_svm_vmrun(struct vcpu_svm *svm, void *arg1,
 
         svm->nested.vmcb_msrpm = nested_vmcb->control.msrpm_base_pa;
 
+        /* cache intercepts */
+        svm->nested.intercept_cr_read    = nested_vmcb->control.intercept_cr_read;
+        svm->nested.intercept_cr_write   = nested_vmcb->control.intercept_cr_write;
+        svm->nested.intercept_dr_read    = nested_vmcb->control.intercept_dr_read;
+        svm->nested.intercept_dr_write   = nested_vmcb->control.intercept_dr_write;
+        svm->nested.intercept_exceptions = nested_vmcb->control.intercept_exceptions;
+        svm->nested.intercept            = nested_vmcb->control.intercept;
+
         force_new_asid(&svm->vcpu);
         svm->vmcb->control.exit_int_info = nested_vmcb->control.exit_int_info;
         svm->vmcb->control.exit_int_info_err = nested_vmcb->control.exit_int_info_err;