[PATCH 1/2] KVM: nVMX: Check Host Address Space Size on vmentry of nested guests

[Krish Sadhukhan <krish.sadhukhan@oracle.com>]

According to section "Checks Related to Address-Space Size" in Intel SDM
vol 3C, the following checks are performed on vmentry of nested guests:

    If the logical processor is outside IA-32e mode (if IA32_EFER.LMA = 0)
    at the time of VM entry, the following must hold:
	- The "IA-32e mode guest" VM-entry control is 0.
	- The "host address-space size" VM-exit control is 0.

    If the logical processor is in IA-32e mode (if IA32_EFER.LMA = 1) at the
    time of VM entry, the "host address-space size" VM-exit control must be 1.

    If the "host address-space size" VM-exit control is 0, the following must
    hold:
	- The "IA-32e mode guest" VM-entry control is 0.
	- Bit 17 of the CR4 field (corresponding to CR4.PCIDE) is 0.
	- Bits 63:32 in the RIP field are 0.

    If the "host address-space size" VM-exit control is 1, the following must
    hold:
	- Bit 5 of the CR4 field (corresponding to CR4.PAE) is 1.
	- The RIP field contains a canonical address.

    On processors that do not support Intel 64 architecture, checks are
    performed to ensure that the "IA-32e mode guest" VM-entry control and the
    "host address-space size" VM-exit control are both 0.

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: Karl Heubaum <karl.heubaum@oracle.com>
---
 arch/x86/kvm/vmx/nested.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index bb509c254939..4de61b069d8c 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2649,6 +2649,34 @@ static int nested_vmx_check_host_state(struct kvm_vcpu *vcpu,
 	    is_noncanonical_address(vmcs12->host_idtr_base, vcpu) ||
 	    is_noncanonical_address(vmcs12->host_tr_base, vcpu))
 		return -EINVAL;
+
+	if (!(vmcs12->host_ia32_efer & EFER_LMA) &&
+	    ((vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) ||
+	    (vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE))) {
+		return -EINVAL;
+	}
+
+	if ((vmcs12->host_ia32_efer & EFER_LMA) &&
+	    !(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE)) {
+		return -EINVAL;
+	}
+
+	if (!(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE) &&
+	    ((vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) ||
+	    (vmcs12->host_cr4 & X86_CR4_PCIDE) ||
+	    (((vmcs12->host_rip) >> 32) & 0xffffffff))) {
+		return -EINVAL;
+	}
+
+	if ((vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE) &&
+	    ((!(vmcs12->host_cr4 & X86_CR4_PAE)) ||
+	    (is_noncanonical_address(vmcs12->host_rip, vcpu)))) {
+		return -EINVAL;
+	}
+#else
+	if (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE ||
+	    vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE)
+		return -EINVAL;
 #endif
 
 	/*
-- 
2.20.1