linux-kernel - [PATCH] KVM: nVMX: cleanup and fix host 64-bit mode checks

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Date:   Wed, 25 Sep 2019 18:34:46 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Jim Mattson <jmattson@...gle.com>,
        Krish Sadhukhan <krish.sadhukhan@...cle.com>
Subject: [PATCH] KVM: nVMX: cleanup and fix host 64-bit mode checks

KVM was incorrectly checking vmcs12->host_ia32_efer even if the "load
IA32_EFER" exit control was reset.  Also, some checks were not using
the new CC macro for tracing.

Cleanup everything so that the vCPU's 64-bit mode is determined
directly from EFER_LMA and the VMCS checks are based on that, which
matches section 26.2.4 of the SDM.

Cc: Sean Christopherson <sean.j.christopherson@...el.com>
Cc: Jim Mattson <jmattson@...gle.com>
Cc: Krish Sadhukhan <krish.sadhukhan@...cle.com>
Fixes: 5845038c111db27902bc220a4f70070fe945871c
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/vmx/nested.c | 53 ++++++++++++++++++++---------------------------
 1 file changed, 22 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 70d59d9304f2..e108847f6cf8 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2664,8 +2664,26 @@ static int nested_vmx_check_host_state(struct kvm_vcpu *vcpu,
 	    CC(!kvm_pat_valid(vmcs12->host_ia32_pat)))
 		return -EINVAL;
 
-	ia32e = (vmcs12->vm_exit_controls &
-		 VM_EXIT_HOST_ADDR_SPACE_SIZE) != 0;
+#ifdef CONFIG_X86_64
+	ia32e = !!(vcpu->arch.efer & EFER_LMA);
+#else
+	if (CC(vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE))
+		return -EINVAL;
+
+	ia32e = false;
+#endif
+
+	if (ia32e) {
+		if (CC(!(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE)) ||
+		    CC(!(vmcs12->host_cr4 & X86_CR4_PAE)))
+			return -EINVAL;
+	} else {
+		if (CC(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE) ||
+		    CC(vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) ||
+		    CC(vmcs12->host_cr4 & X86_CR4_PCIDE) ||
+		    CC(((vmcs12->host_rip) >> 32) & 0xffffffff))
+			return -EINVAL;
+	}
 
 	if (CC(vmcs12->host_cs_selector & (SEGMENT_RPL_MASK | SEGMENT_TI_MASK)) ||
 	    CC(vmcs12->host_ss_selector & (SEGMENT_RPL_MASK | SEGMENT_TI_MASK)) ||
@@ -2684,35 +2702,8 @@ static int nested_vmx_check_host_state(struct kvm_vcpu *vcpu,
 	    CC(is_noncanonical_address(vmcs12->host_gs_base, vcpu)) ||
 	    CC(is_noncanonical_address(vmcs12->host_gdtr_base, vcpu)) ||
 	    CC(is_noncanonical_address(vmcs12->host_idtr_base, vcpu)) ||
-	    CC(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)
+	    CC(is_noncanonical_address(vmcs12->host_tr_base, vcpu)) ||
+	    CC(is_noncanonical_address(vmcs12->host_rip, vcpu)))
 		return -EINVAL;
 #endif
 
-- 
1.8.3.1