[PATCH 28/47] KVM: SVM: move special nested exit handling to separate function

From: Avi Kivity
Date: Wed Aug 26 2009 - 06:37:59 EST


From: Joerg Roedel <joerg.roedel@xxxxxxx>

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@xxxxxxx>
Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
---
arch/x86/kvm/svm.c | 80 ++++++++++++++++++++++++++++++++-------------------
1 files changed, 50 insertions(+), 30 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 2edf2dd..e9e3931 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;
}
@@ -1468,31 +1472,39 @@ 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);
@@ -1500,42 +1512,42 @@ 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);
}
@@ -2315,10 +2327,18 @@ 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;
}

--
1.6.4.1

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