KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX)

mainline inclusion
from mainline-5.13
commit 54f958cd
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I5EZEK
CVE: NA

Intel-SIG: commit 54f958cd KVM: x86: Export
kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX).
Backport for SGX virtualization support

--------------------------------

Export the gva_to_gpa() helpers for use by SGX virtualization when
executing ENCLS[ECREATE] and ENCLS[EINIT] on behalf of the guest.
To execute ECREATE and EINIT, KVM must obtain the GPA of the target
Secure Enclave Control Structure (SECS) in order to get its
corresponding HVA.

Because the SECS must reside in the Enclave Page Cache (EPC), copying
the SECS's data to a host-controlled buffer via existing exported
helpers is not a viable option as the EPC is not readable or writable
by the kernel.

SGX virtualization will also use gva_to_gpa() to obtain HVAs for
non-EPC pages in order to pass user pointers directly to ECREATE and
EINIT, which avoids having to copy pages worth of data into the kernel.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Acked-by: NJarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: NKai Huang <kai.huang@intel.com>
Message-Id: <02f37708321bcdfaa2f9d41c8478affa6e84b04d.1618196135.git.kai.huang@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NFan Du <fan.du@intel.com>
Signed-off-by: NZhiquan Li <zhiquan1.li@intel.com>

arch/x86/kvm/x86.c

@@ -6005,6 +6005,7 @@ gpa_t kvm_mmu_gva_to_gpa_read(struct kvm_vcpu *vcpu, gva_t gva,
 	u32 access = (kvm_x86_ops.get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
 	return vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, exception);
 }
+EXPORT_SYMBOL_GPL(kvm_mmu_gva_to_gpa_read);
 
  gpa_t kvm_mmu_gva_to_gpa_fetch(struct kvm_vcpu *vcpu, gva_t gva,
 				struct x86_exception *exception)
@@ -6021,6 +6022,7 @@ gpa_t kvm_mmu_gva_to_gpa_write(struct kvm_vcpu *vcpu, gva_t gva,
 	access |= PFERR_WRITE_MASK;
 	return vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, exception);
 }
+EXPORT_SYMBOL_GPL(kvm_mmu_gva_to_gpa_write);
 
 /* uses this to access any guest's mapped memory without checking CPL */
 gpa_t kvm_mmu_gva_to_gpa_system(struct kvm_vcpu *vcpu, gva_t gva,