KVM: SVM: move special nested exit handling to separate function

This patch moves the handling for special nested vmexits like #pf to a
separate function. This makes the kvm_override parameter obsolete and
makes the code more readable.

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

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 53376f1..be28a38 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -47,6 +47,10 @@ MODULE_LICENSE("GPL");
 #define SVM_FEATURE_LBRV (1 << 1)
 #define SVM_FEATURE_SVML (1 << 2)
 
+#define NESTED_EXIT_HOST       0       /* Exit handled on host level */
+#define NESTED_EXIT_DONE       1       /* Exit caused nested vmexit  */
+#define NESTED_EXIT_CONTINUE   2       /* Further checks needed      */
+
 #define DEBUGCTL_RESERVED_BITS (~(0x3fULL))
 
 /* Turn on to get debugging output*/
@@ -126,7 +130,7 @@ module_param(nested, int, S_IRUGO);
 static void svm_flush_tlb(struct kvm_vcpu *vcpu);
 static void svm_complete_interrupts(struct vcpu_svm *svm);
 
-static int nested_svm_exit_handled(struct vcpu_svm *svm, bool kvm_override);
+static int nested_svm_exit_handled(struct vcpu_svm *svm);
 static int nested_svm_vmexit(struct vcpu_svm *svm);
 static int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
                                      bool has_error_code, u32 error_code);
@@ -1365,7 +1369,7 @@ static int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
        svm->vmcb->control.exit_info_1 = error_code;
        svm->vmcb->control.exit_info_2 = svm->vcpu.arch.cr2;
 
-       return nested_svm_exit_handled(svm, false);
+       return nested_svm_exit_handled(svm);
 }
 
 static inline int nested_svm_intr(struct vcpu_svm *svm)
@@ -1379,7 +1383,7 @@ static inline int nested_svm_intr(struct vcpu_svm *svm)
 
                svm->vmcb->control.exit_code = SVM_EXIT_INTR;
 
-               if (nested_svm_exit_handled(svm, false)) {
+               if (nested_svm_exit_handled(svm)) {
                        nsvm_printk("VMexit -> INTR\n");
                        return 1;
                }
@@ -1465,31 +1469,39 @@ out:
        return ret;
 }
 
-static int nested_svm_exit_handled(struct vcpu_svm *svm, bool kvm_override)
+static int nested_svm_exit_special(struct vcpu_svm *svm)
 {
        u32 exit_code = svm->vmcb->control.exit_code;
-       bool vmexit = false;
 
-       if (kvm_override) {
-               switch (exit_code) {
-               case SVM_EXIT_INTR:
-               case SVM_EXIT_NMI:
-                       return 0;
+       switch (exit_code) {
+       case SVM_EXIT_INTR:
+       case SVM_EXIT_NMI:
+               return NESTED_EXIT_HOST;
                /* For now we are always handling NPFs when using them */
-               case SVM_EXIT_NPF:
-                       if (npt_enabled)
-                               return 0;
-                       break;
-               /* When we're shadowing, trap PFs */
-               case SVM_EXIT_EXCP_BASE + PF_VECTOR:
-                       if (!npt_enabled)
-                               return 0;
-                       break;
-               default:
-                       break;
-               }
+       case SVM_EXIT_NPF:
+               if (npt_enabled)
+                       return NESTED_EXIT_HOST;
+               break;
+       /* When we're shadowing, trap PFs */
+       case SVM_EXIT_EXCP_BASE + PF_VECTOR:
+               if (!npt_enabled)
+                       return NESTED_EXIT_HOST;
+               break;
+       default:
+               break;
        }
 
+       return NESTED_EXIT_CONTINUE;
+}
+
+/*
+ * If this function returns true, this #vmexit was already handled
+ */
+static int nested_svm_exit_handled(struct vcpu_svm *svm)
+{
+       u32 exit_code = svm->vmcb->control.exit_code;
+       int vmexit = NESTED_EXIT_HOST;
+
        switch (exit_code) {
        case SVM_EXIT_MSR:
                vmexit = nested_svm_exit_handled_msr(svm);
@@ -1497,42 +1509,42 @@ static int nested_svm_exit_handled(struct vcpu_svm *svm, bool kvm_override)
        case SVM_EXIT_READ_CR0 ... SVM_EXIT_READ_CR8: {
                u32 cr_bits = 1 << (exit_code - SVM_EXIT_READ_CR0);
                if (svm->nested.intercept_cr_read & cr_bits)
-                       vmexit = true;
+                       vmexit = NESTED_EXIT_DONE;
                break;
        }
        case SVM_EXIT_WRITE_CR0 ... SVM_EXIT_WRITE_CR8: {
                u32 cr_bits = 1 << (exit_code - SVM_EXIT_WRITE_CR0);
                if (svm->nested.intercept_cr_write & cr_bits)
-                       vmexit = true;
+                       vmexit = NESTED_EXIT_DONE;
                break;
        }
        case SVM_EXIT_READ_DR0 ... SVM_EXIT_READ_DR7: {
                u32 dr_bits = 1 << (exit_code - SVM_EXIT_READ_DR0);
                if (svm->nested.intercept_dr_read & dr_bits)
-                       vmexit = true;
+                       vmexit = NESTED_EXIT_DONE;
                break;
        }
        case SVM_EXIT_WRITE_DR0 ... SVM_EXIT_WRITE_DR7: {
                u32 dr_bits = 1 << (exit_code - SVM_EXIT_WRITE_DR0);
                if (svm->nested.intercept_dr_write & dr_bits)
-                       vmexit = true;
+                       vmexit = NESTED_EXIT_DONE;
                break;
        }
        case SVM_EXIT_EXCP_BASE ... SVM_EXIT_EXCP_BASE + 0x1f: {
                u32 excp_bits = 1 << (exit_code - SVM_EXIT_EXCP_BASE);
                if (svm->nested.intercept_exceptions & excp_bits)
-                       vmexit = true;
+                       vmexit = NESTED_EXIT_DONE;
                break;
        }
        default: {
                u64 exit_bits = 1ULL << (exit_code - SVM_EXIT_INTR);
                nsvm_printk("exit code: 0x%x\n", exit_code);
                if (svm->nested.intercept & exit_bits)
-                       vmexit = true;
+                       vmexit = NESTED_EXIT_DONE;
        }
        }
 
-       if (vmexit) {
+       if (vmexit == NESTED_EXIT_DONE) {
                nsvm_printk("#VMEXIT reason=%04x\n", exit_code);
                nested_svm_vmexit(svm);
        }
@@ -2312,10 +2324,18 @@ static int handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
        trace_kvm_exit(exit_code, svm->vmcb->save.rip);
 
        if (is_nested(svm)) {
+               int vmexit;
+
                nsvm_printk("nested handle_exit: 0x%x | 0x%lx | 0x%lx | 0x%lx\n",
                            exit_code, svm->vmcb->control.exit_info_1,
                            svm->vmcb->control.exit_info_2, svm->vmcb->save.rip);
-               if (nested_svm_exit_handled(svm, true))
+
+               vmexit = nested_svm_exit_special(svm);
+
+               if (vmexit == NESTED_EXIT_CONTINUE)
+                       vmexit = nested_svm_exit_handled(svm);
+
+               if (vmexit == NESTED_EXIT_DONE)
                        return 1;
        }