Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 68f89400 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Avi Kivity
Browse files

KVM: VMX: EPT misconfiguration handler 



Handler for EPT misconfiguration which checks for valid state
in the shadow pagetables, printing the spte on each level.

The separate WARN_ONs are useful for kerneloops.org.

Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 94d8b056

arch/x86/kvm/vmx.c

+85 −1
Original line number Diff line number Diff line
@@ -3227,6 +3227,89 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
	return kvm_mmu_page_fault(vcpu, gpa & PAGE_MASK, 0);

}



static u64 ept_rsvd_mask(u64 spte, int level)

{

	int i;

	u64 mask = 0;



	for (i = 51; i > boot_cpu_data.x86_phys_bits; i--)

		mask |= (1ULL << i);



	if (level > 2)

		/* bits 7:3 reserved */

		mask |= 0xf8;

	else if (level == 2) {

		if (spte & (1ULL << 7))

			/* 2MB ref, bits 20:12 reserved */

			mask |= 0x1ff000;

		else

			/* bits 6:3 reserved */

			mask |= 0x78;

	}



	return mask;

}



static void ept_misconfig_inspect_spte(struct kvm_vcpu *vcpu, u64 spte,

				       int level)

{

	printk(KERN_ERR "%s: spte 0x%llx level %d\n", __func__, spte, level);



	/* 010b (write-only) */

	WARN_ON((spte & 0x7) == 0x2);



	/* 110b (write/execute) */

	WARN_ON((spte & 0x7) == 0x6);



	/* 100b (execute-only) and value not supported by logical processor */

	if (!cpu_has_vmx_ept_execute_only())

		WARN_ON((spte & 0x7) == 0x4);



	/* not 000b */

	if ((spte & 0x7)) {

		u64 rsvd_bits = spte & ept_rsvd_mask(spte, level);



		if (rsvd_bits != 0) {

			printk(KERN_ERR "%s: rsvd_bits = 0x%llx\n",

					 __func__, rsvd_bits);

			WARN_ON(1);

		}



		if (level == 1 || (level == 2 && (spte & (1ULL << 7)))) {

			u64 ept_mem_type = (spte & 0x38) >> 3;



			if (ept_mem_type == 2 || ept_mem_type == 3 ||

			    ept_mem_type == 7) {

				printk(KERN_ERR "%s: ept_mem_type=0x%llx\n",

						__func__, ept_mem_type);

				WARN_ON(1);

			}

		}

	}

}



static int handle_ept_misconfig(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)

{

	u64 sptes[4];

	int nr_sptes, i;

	gpa_t gpa;



	gpa = vmcs_read64(GUEST_PHYSICAL_ADDRESS);



	printk(KERN_ERR "EPT: Misconfiguration.\n");

	printk(KERN_ERR "EPT: GPA: 0x%llx\n", gpa);



	nr_sptes = kvm_mmu_get_spte_hierarchy(vcpu, gpa, sptes);



	for (i = PT64_ROOT_LEVEL; i > PT64_ROOT_LEVEL - nr_sptes; --i)

		ept_misconfig_inspect_spte(vcpu, sptes[i-1], i);



	kvm_run->exit_reason = KVM_EXIT_UNKNOWN;

	kvm_run->hw.hardware_exit_reason = EXIT_REASON_EPT_MISCONFIG;



	return 0;

}



static int handle_nmi_window(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)

{

	u32 cpu_based_vm_exec_control;
@@ -3306,8 +3389,9 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu, 
	[EXIT_REASON_APIC_ACCESS]             = handle_apic_access,

	[EXIT_REASON_WBINVD]                  = handle_wbinvd,

	[EXIT_REASON_TASK_SWITCH]             = handle_task_switch,

	[EXIT_REASON_EPT_VIOLATION]	      = handle_ept_violation,

	[EXIT_REASON_MCE_DURING_VMENTRY]      = handle_machine_check,

	[EXIT_REASON_EPT_VIOLATION]	      = handle_ept_violation,

	[EXIT_REASON_EPT_MISCONFIG]           = handle_ept_misconfig,

};



static const int kvm_vmx_max_exit_handlers =