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Subject[PATCH 2/3 v2] KVM: nVMX: Enable VMFUNC for the L1 hypervisor
Date
Expose VMFUNC in MSRs and VMCS fields. No actual VMFUNCs are enabled.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Bandan Das <bsd@redhat.com>
---
arch/x86/kvm/vmx.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 51 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index a483b49..7364678 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -240,6 +240,7 @@ struct __packed vmcs12 {
u64 virtual_apic_page_addr;
u64 apic_access_addr;
u64 posted_intr_desc_addr;
+ u64 vm_function_control;
u64 ept_pointer;
u64 eoi_exit_bitmap0;
u64 eoi_exit_bitmap1;
@@ -481,6 +482,7 @@ struct nested_vmx {
u64 nested_vmx_cr4_fixed0;
u64 nested_vmx_cr4_fixed1;
u64 nested_vmx_vmcs_enum;
+ u64 nested_vmx_vmfunc_controls;
};

#define POSTED_INTR_ON 0
@@ -763,6 +765,7 @@ static const unsigned short vmcs_field_to_offset_table[] = {
FIELD64(VIRTUAL_APIC_PAGE_ADDR, virtual_apic_page_addr),
FIELD64(APIC_ACCESS_ADDR, apic_access_addr),
FIELD64(POSTED_INTR_DESC_ADDR, posted_intr_desc_addr),
+ FIELD64(VM_FUNCTION_CONTROL, vm_function_control),
FIELD64(EPT_POINTER, ept_pointer),
FIELD64(EOI_EXIT_BITMAP0, eoi_exit_bitmap0),
FIELD64(EOI_EXIT_BITMAP1, eoi_exit_bitmap1),
@@ -1394,6 +1397,11 @@ static inline bool nested_cpu_has_posted_intr(struct vmcs12 *vmcs12)
return vmcs12->pin_based_vm_exec_control & PIN_BASED_POSTED_INTR;
}

+static inline bool nested_cpu_has_vmfunc(struct vmcs12 *vmcs12)
+{
+ return nested_cpu_has2(vmcs12, SECONDARY_EXEC_ENABLE_VMFUNC);
+}
+
static inline bool is_nmi(u32 intr_info)
{
return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VALID_MASK))
@@ -2780,6 +2788,12 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
} else
vmx->nested.nested_vmx_ept_caps = 0;

+ if (cpu_has_vmx_vmfunc()) {
+ vmx->nested.nested_vmx_secondary_ctls_high |=
+ SECONDARY_EXEC_ENABLE_VMFUNC;
+ vmx->nested.nested_vmx_vmfunc_controls = 0;
+ }
+
/*
* Old versions of KVM use the single-context version without
* checking for support, so declare that it is supported even
@@ -3149,6 +3163,9 @@ static int vmx_get_vmx_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
*pdata = vmx->nested.nested_vmx_ept_caps |
((u64)vmx->nested.nested_vmx_vpid_caps << 32);
break;
+ case MSR_IA32_VMX_VMFUNC:
+ *pdata = vmx->nested.nested_vmx_vmfunc_controls;
+ break;
default:
return 1;
}
@@ -7752,7 +7769,29 @@ static int handle_preemption_timer(struct kvm_vcpu *vcpu)

static int handle_vmfunc(struct kvm_vcpu *vcpu)
{
- kvm_queue_exception(vcpu, UD_VECTOR);
+ struct vcpu_vmx *vmx = to_vmx(vcpu);
+ struct vmcs12 *vmcs12;
+ u32 function = vcpu->arch.regs[VCPU_REGS_RAX];
+
+ /*
+ * VMFUNC is only supported for nested guests, but we always enable the
+ * secondary control for simplicity; for non-nested mode, fake that we
+ * didn't by injecting #UD.
+ */
+ if (!is_guest_mode(vcpu)) {
+ kvm_queue_exception(vcpu, UD_VECTOR);
+ return 1;
+ }
+
+ vmcs12 = get_vmcs12(vcpu);
+ if ((vmcs12->vm_function_control & (1 << function)) == 0)
+ goto fail;
+ WARN(1, "VMCS12 VM function control should have been zero");
+
+fail:
+ nested_vmx_vmexit(vcpu, vmx->exit_reason,
+ vmcs_read32(VM_EXIT_INTR_INFO),
+ vmcs_readl(EXIT_QUALIFICATION));
return 1;
}

@@ -10053,7 +10092,8 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
exec_control &= ~(SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
SECONDARY_EXEC_RDTSCP |
SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
- SECONDARY_EXEC_APIC_REGISTER_VIRT);
+ SECONDARY_EXEC_APIC_REGISTER_VIRT |
+ SECONDARY_EXEC_ENABLE_VMFUNC);
if (nested_cpu_has(vmcs12,
CPU_BASED_ACTIVATE_SECONDARY_CONTROLS)) {
vmcs12_exec_ctrl = vmcs12->secondary_vm_exec_control &
@@ -10061,6 +10101,10 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
exec_control |= vmcs12_exec_ctrl;
}

+ /* All VMFUNCs are currently emulated through L0 vmexits. */
+ if (exec_control & SECONDARY_EXEC_ENABLE_VMFUNC)
+ vmcs_write64(VM_FUNCTION_CONTROL, 0);
+
if (exec_control & SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY) {
vmcs_write64(EOI_EXIT_BITMAP0,
vmcs12->eoi_exit_bitmap0);
@@ -10310,6 +10354,11 @@ static int check_vmentry_prereqs(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
vmx->nested.nested_vmx_entry_ctls_high))
return VMXERR_ENTRY_INVALID_CONTROL_FIELD;

+ if (nested_cpu_has_vmfunc(vmcs12) &&
+ (vmcs12->vm_function_control &
+ ~vmx->nested.nested_vmx_vmfunc_controls))
+ return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
+
if (vmcs12->cr3_target_count > nested_cpu_vmx_misc_cr3_count(vcpu))
return VMXERR_ENTRY_INVALID_CONTROL_FIELD;

--
2.9.4
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