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KVM: x86: simplify handling of PKRU

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Move it to struct kvm_arch_vcpu, replacing guest_pkru_valid with a
simple comparison against the host value of the register.  The write of
PKRU in addition can be skipped if the guest has not enabled the feature.
Once we do this, we need not test OSPKE in the host anymore, because
guest_CR4.PKE=1 implies host_CR4.PKE=1.

The static PKU test is kept to elide the code on older CPUs.

Suggested-by: Yang Zhang <zy107165@alibaba-inc.com>
Fixes: 1be0e61c1f
Cc: stable@vger.kernel.org
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini
2017-08-23 23:14:38 +02:00
parent c469268cd5
commit b9dd21e104
5 changed files with 10 additions and 30 deletions
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2
arch/x86/kvm/mmu.h
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@ -185,7 +185,7 @@ static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
* index of the protection domain, so pte_pkey * 2 is
* is the index of the first bit for the domain.
*/
pkru_bits = (kvm_read_pkru(vcpu) >> (pte_pkey * 2)) & 3;
pkru_bits = (vcpu->arch.pkru >> (pte_pkey * 2)) & 3;
/* clear present bit, replace PFEC.RSVD with ACC_USER_MASK. */
offset = (pfec & ~1) +