kvm: nVMX: Allow L1 to intercept software exceptions (#BP and #OF)

When L2 exits to L0 due to "exception or NMI", software exceptions
(#BP and #OF) for which L1 has requested an intercept should be
handled by L1 rather than L0. Previously, only hardware exceptions
were forwarded to L1.

Signed-off-by: Jim Mattson <jmattson@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
static int vmx_restore_vmx_misc(struct vcpu_vmx *vmx, u64 data)
{
	const u64 feature_and_reserved_bits =
		/* feature */
		BIT_ULL(5) | GENMASK_ULL(8, 6) | BIT_ULL(14) | BIT_ULL(15) |
		BIT_ULL(28) | BIT_ULL(29) | BIT_ULL(30) |
		/* reserved */
		GENMASK_ULL(13, 9) | BIT_ULL(31);
	u64 vmx_misc;

	vmx_misc = vmx_control_msr(vmx->nested.nested_vmx_misc_low,
				   vmx->nested.nested_vmx_misc_high);

	if (!is_bitwise_subset(vmx_misc, data, feature_and_reserved_bits))
		return -EINVAL;

	if ((vmx->nested.nested_vmx_pinbased_ctls_high &
	     PIN_BASED_VMX_PREEMPTION_TIMER) &&
	    vmx_misc_preemption_timer_rate(data) !=
	    vmx_misc_preemption_timer_rate(vmx_misc))
		return -EINVAL;

	if (vmx_misc_cr3_count(data) > vmx_misc_cr3_count(vmx_misc))
		return -EINVAL;

	if (vmx_misc_max_msr(data) > vmx_misc_max_msr(vmx_misc))
		return -EINVAL;

	if (vmx_misc_mseg_revid(data) != vmx_misc_mseg_revid(vmx_misc))
		return -EINVAL;

	vmx->nested.nested_vmx_misc_low = data;
	vmx->nested.nested_vmx_misc_high = data >> 32;
	return 0;
}

static int vmx_restore_vmx_misc(struct vcpu_vmx *vmx, u64 data)
{
	const u64 feature_and_reserved_bits =
		/* feature */
		BIT_ULL(5) | GENMASK_ULL(8, 6) | BIT_ULL(14) | BIT_ULL(15) |
		BIT_ULL(28) | BIT_ULL(29) | BIT_ULL(30) |
		/* reserved */
		GENMASK_ULL(13, 9) | BIT_ULL(31);
	u64 vmx_misc;

	vmx_misc = vmx_control_msr(vmx->nested.nested_vmx_misc_low,
				   vmx->nested.nested_vmx_misc_high);

	if (!is_bitwise_subset(vmx_misc, data, feature_and_reserved_bits))
		return -EINVAL;

	if ((vmx->nested.nested_vmx_pinbased_ctls_high &
	     PIN_BASED_VMX_PREEMPTION_TIMER) &&
	    vmx_misc_preemption_timer_rate(data) !=
	    vmx_misc_preemption_timer_rate(vmx_misc))
		return -EINVAL;

	if (vmx_misc_cr3_count(data) > vmx_misc_cr3_count(vmx_misc))
		return -EINVAL;

	if (vmx_misc_max_msr(data) > vmx_misc_max_msr(vmx_misc))
		return -EINVAL;

	if (vmx_misc_mseg_revid(data) != vmx_misc_mseg_revid(vmx_misc))
		return -EINVAL;

	vmx->nested.nested_vmx_misc_low = data;
	vmx->nested.nested_vmx_misc_high = data >> 32;
	return 0;
}
