Commit b91991bf authored by Krish Sadhukhan's avatar Krish Sadhukhan Committed by Paolo Bonzini
Browse files

KVM: nVMX: Check GUEST_DR7 on vmentry of nested guests 



According to section "Checks on Guest Control Registers, Debug Registers, and
and MSRs" in Intel SDM vol 3C, the following checks are performed on vmentry
of nested guests:

    If the "load debug controls" VM-entry control is 1, bits 63:32 in the DR7
    field must be 0.

In KVM, GUEST_DR7 is set prior to the vmcs02 VM-entry by kvm_set_dr() and the
latter synthesizes a #GP if any bit in the high dword in the former is set.
Hence this field needs to be checked in software.

Signed-off-by: default avatarKrish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: default avatarKarl Heubaum <karl.heubaum@oracle.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent e174bb94

arch/x86/kvm/vmx/nested.c

+4 −0
Original line number Diff line number Diff line
@@ -2887,6 +2887,10 @@ static int nested_vmx_check_guest_state(struct kvm_vcpu *vcpu, 
	    CC(!nested_guest_cr4_valid(vcpu, vmcs12->guest_cr4)))

		return -EINVAL;



	if ((vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS) &&

	    CC(!kvm_dr7_valid(vmcs12->guest_dr7)))

		return -EINVAL;



	if ((vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_PAT) &&

	    CC(!kvm_pat_valid(vmcs12->guest_ia32_pat)))

		return -EINVAL;

arch/x86/kvm/x86.c

+1 −1
Original line number Diff line number Diff line
@@ -1082,7 +1082,7 @@ static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val) 
	case 5:

		/* fall through */

	default: /* 7 */

		if (val & 0xffffffff00000000ULL)

		if (!kvm_dr7_valid(val))

			return -1; /* #GP */

		vcpu->arch.dr7 = (val & DR7_VOLATILE) | DR7_FIXED_1;

		kvm_update_dr7(vcpu);

arch/x86/kvm/x86.h

+6 −0
Original line number Diff line number Diff line
@@ -357,6 +357,12 @@ static inline bool kvm_pat_valid(u64 data) 
	return (data | ((data & 0x0202020202020202ull) << 1)) == data;

}



static inline bool kvm_dr7_valid(unsigned long data)

{

	/* Bits [63:32] are reserved */

	return !(data >> 32);

}



void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu);

void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu);

u64 kvm_spec_ctrl_valid_bits(struct kvm_vcpu *vcpu);

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