From: Paolo Bonzini <pbonzini@redhat.com>
Date: Mon, 24 Feb 2014 11:15:16 +0000 (+0100)
Subject: KVM: x86: introduce kvm_supported_xcr0()
X-Git-Tag: v3.15-rc1~118^2~16
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4ff417320c2dfc984ec1939a7da888976441a881;p=pandora-kernel.git

KVM: x86: introduce kvm_supported_xcr0()

XSAVE support for KVM is already using host_xcr0 & KVM_SUPPORTED_XCR0 as
a "dynamic" version of KVM_SUPPORTED_XCR0.

However, this is not enough because the MPX bits should not be presented
to the guest unless kvm_x86_ops confirms the support.  So, replace all
instances of host_xcr0 & KVM_SUPPORTED_XCR0 with a new function
kvm_supported_xcr0() that also has this check.

Note that here:

		if (xstate_bv & ~KVM_SUPPORTED_XCR0)
			return -EINVAL;
		if (xstate_bv & ~host_cr0)
			return -EINVAL;

the code is equivalent to

		if ((xstate_bv & ~KVM_SUPPORTED_XCR0) ||
		    (xstate_bv & ~host_cr0)
			return -EINVAL;

i.e. "xstate_bv & (~KVM_SUPPORTED_XCR0 | ~host_cr0)" which is in turn
equal to "xstate_bv & ~(KVM_SUPPORTED_XCR0 & host_cr0)".  So we should
also use the new function there.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---

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