KVM: nVMX: Enable nested virtualize x2apic mode
When L2 is using x2apic, we can use virtualize x2apic mode to
gain higher performance, especially in apicv case.
This patch also introduces nested_vmx_check_apicv_controls
for the nested apicv patches.
Signed-off-by: Wincy Van <fanwenyi0529@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 6d1d26f..25984e7 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1115,6 +1115,11 @@
vmx_xsaves_supported();
}
+static inline bool nested_cpu_has_virt_x2apic_mode(struct vmcs12 *vmcs12)
+{
+ return nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE);
+}
+
static inline bool is_exception(u32 intr_info)
{
return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VALID_MASK))
@@ -2402,6 +2407,7 @@
nested_vmx_secondary_ctls_low = 0;
nested_vmx_secondary_ctls_high &=
SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
+ SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE |
SECONDARY_EXEC_WBINVD_EXITING |
SECONDARY_EXEC_XSAVES;
@@ -4163,6 +4169,52 @@
}
}
+/*
+ * If a msr is allowed by L0, we should check whether it is allowed by L1.
+ * The corresponding bit will be cleared unless both of L0 and L1 allow it.
+ */
+static void nested_vmx_disable_intercept_for_msr(unsigned long *msr_bitmap_l1,
+ unsigned long *msr_bitmap_nested,
+ u32 msr, int type)
+{
+ int f = sizeof(unsigned long);
+
+ if (!cpu_has_vmx_msr_bitmap()) {
+ WARN_ON(1);
+ return;
+ }
+
+ /*
+ * See Intel PRM Vol. 3, 20.6.9 (MSR-Bitmap Address). Early manuals
+ * have the write-low and read-high bitmap offsets the wrong way round.
+ * We can control MSRs 0x00000000-0x00001fff and 0xc0000000-0xc0001fff.
+ */
+ if (msr <= 0x1fff) {
+ if (type & MSR_TYPE_R &&
+ !test_bit(msr, msr_bitmap_l1 + 0x000 / f))
+ /* read-low */
+ __clear_bit(msr, msr_bitmap_nested + 0x000 / f);
+
+ if (type & MSR_TYPE_W &&
+ !test_bit(msr, msr_bitmap_l1 + 0x800 / f))
+ /* write-low */
+ __clear_bit(msr, msr_bitmap_nested + 0x800 / f);
+
+ } else if ((msr >= 0xc0000000) && (msr <= 0xc0001fff)) {
+ msr &= 0x1fff;
+ if (type & MSR_TYPE_R &&
+ !test_bit(msr, msr_bitmap_l1 + 0x400 / f))
+ /* read-high */
+ __clear_bit(msr, msr_bitmap_nested + 0x400 / f);
+
+ if (type & MSR_TYPE_W &&
+ !test_bit(msr, msr_bitmap_l1 + 0xc00 / f))
+ /* write-high */
+ __clear_bit(msr, msr_bitmap_nested + 0xc00 / f);
+
+ }
+}
+
static void vmx_disable_intercept_for_msr(u32 msr, bool longmode_only)
{
if (!longmode_only)
@@ -8500,7 +8552,59 @@
static inline bool nested_vmx_merge_msr_bitmap(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12)
{
- return false;
+ struct page *page;
+ unsigned long *msr_bitmap;
+
+ if (!nested_cpu_has_virt_x2apic_mode(vmcs12))
+ return false;
+
+ page = nested_get_page(vcpu, vmcs12->msr_bitmap);
+ if (!page) {
+ WARN_ON(1);
+ return false;
+ }
+ msr_bitmap = (unsigned long *)kmap(page);
+ if (!msr_bitmap) {
+ nested_release_page_clean(page);
+ WARN_ON(1);
+ return false;
+ }
+
+ if (nested_cpu_has_virt_x2apic_mode(vmcs12)) {
+ /* TPR is allowed */
+ nested_vmx_disable_intercept_for_msr(msr_bitmap,
+ vmx_msr_bitmap_nested,
+ APIC_BASE_MSR + (APIC_TASKPRI >> 4),
+ MSR_TYPE_R | MSR_TYPE_W);
+ } else
+ __vmx_enable_intercept_for_msr(
+ vmx_msr_bitmap_nested,
+ APIC_BASE_MSR + (APIC_TASKPRI >> 4),
+ MSR_TYPE_R | MSR_TYPE_W);
+ kunmap(page);
+ nested_release_page_clean(page);
+
+ return true;
+}
+
+static int nested_vmx_check_apicv_controls(struct kvm_vcpu *vcpu,
+ struct vmcs12 *vmcs12)
+{
+ if (!nested_cpu_has_virt_x2apic_mode(vmcs12))
+ return 0;
+
+ /*
+ * If virtualize x2apic mode is enabled,
+ * virtualize apic access must be disabled.
+ */
+ if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES))
+ return -EINVAL;
+
+ /* tpr shadow is needed by all apicv features. */
+ if (!nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW))
+ return -EINVAL;
+
+ return 0;
}
static int nested_vmx_check_msr_switch(struct kvm_vcpu *vcpu,
@@ -8796,7 +8900,8 @@
else
vmcs_write64(APIC_ACCESS_ADDR,
page_to_phys(vmx->nested.apic_access_page));
- } else if (vm_need_virtualize_apic_accesses(vmx->vcpu.kvm)) {
+ } else if (!(nested_cpu_has_virt_x2apic_mode(vmcs12)) &&
+ (vm_need_virtualize_apic_accesses(vmx->vcpu.kvm))) {
exec_control |=
SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
kvm_vcpu_reload_apic_access_page(vcpu);
@@ -9007,6 +9112,11 @@
return 1;
}
+ if (nested_vmx_check_apicv_controls(vcpu, vmcs12)) {
+ nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
+ return 1;
+ }
+
if (nested_vmx_check_msr_switch_controls(vcpu, vmcs12)) {
nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
return 1;