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>

1 files changed, 50 insertions, 30 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 53376f144d70..be28a38db918 100644
--- 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;
         }