[PATCH v6 3/7] KVM: nVMX: Move guest non-reg state checks to VM-Exit path

Sean Christopherson
2019-04-11T19:18:17Z

Per Intel's SDM, volume 3, section Checking and Loading Guest State:

Because the checking and the loading occur concurrently, a failure may
be discovered only after some state has been loaded. For this reason,
the logical processor responds to such failures by loading state from
the host-state area, as it would for a VM exit.

In other words, a failed non-register state consistency check results in
a VM-Exit, not VM-Fail. Moving the non-reg state checks also paves the
way for renaming nested_vmx_check_vmentry_postreqs() to align with the
SDM, i.e. nested_vmx_check_vmentry_guest_state().

Fixes: 26539bd0e446a ("KVM: nVMX: check vmcs12 for valid activity state")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/vmx/nested.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index f487aae3233e..fe1323ab6894 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2612,18 +2612,6 @@ static int nested_check_host_control_regs(struct kvm_vcpu *vcpu,
return 0;
}

-/*
- * Checks related to Guest Non-register State
- */
-static int nested_check_guest_non_reg_state(struct vmcs12 *vmcs12)
-{
- if (vmcs12->guest_activity_state != GUEST_ACTIVITY_ACTIVE &&
- vmcs12->guest_activity_state != GUEST_ACTIVITY_HLT)
- return -EINVAL;
-
- return 0;
-}
-
static int nested_vmx_check_vmentry_prereqs(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12)
{
@@ -2635,9 +2623,6 @@ static int nested_vmx_check_vmentry_prereqs(struct kvm_vcpu *vcpu,
if (nested_check_host_control_regs(vcpu, vmcs12))
return VMXERR_ENTRY_INVALID_HOST_STATE_FIELD;

- if (nested_check_guest_non_reg_state(vmcs12))
- return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
-
return 0;
}

@@ -2668,6 +2653,18 @@ static int nested_vmx_check_vmcs_link_ptr(struct kvm_vcpu *vcpu,
return r;
}

+/*
+ * Checks related to Guest Non-register State
+ */
+static int nested_check_guest_non_reg_state(struct vmcs12 *vmcs12)
+{
+ if (vmcs12->guest_activity_state != GUEST_ACTIVITY_ACTIVE &&
+ vmcs12->guest_activity_state != GUEST_ACTIVITY_HLT)
+ return -EINVAL;
+
+ return 0;
+}
+
static int nested_vmx_check_vmentry_postreqs(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12,
u32 *exit_qual)
@@ -2713,6 +2710,9 @@ static int nested_vmx_check_vmentry_postreqs(struct kvm_vcpu *vcpu,
(vmcs12->guest_bndcfgs & MSR_IA32_BNDCFGS_RSVD)))
return 1;

+ if (nested_check_guest_non_reg_state(vmcs12))
+ return 1;
+
return 0;
}

--
2.21.0