[PATCH 5.15 123/917] KVM: x86: Add helper to consolidate core logic of SET_CPUID{2} flows

Greg Kroah-Hartman
2021-11-16T01:07:40Z

From: Sean Christopherson <seanjc@google.com>

commit 8b44b174f6aca815fc84c2038e4523ef8e32fabb upstream.

Move the core logic of SET_CPUID and SET_CPUID2 to a common helper, the
only difference between the two ioctls() is the format of the userspace
struct. A future fix will add yet more code to the core logic.

No functional change intended.

Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211105095101.5384-2-pdurrant@amazon.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/cpuid.c | 47 ++++++++++++++++++++++++-----------------------
1 file changed, 24 insertions(+), 23 deletions(-)

--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -232,6 +232,25 @@ u64 kvm_vcpu_reserved_gpa_bits_raw(struc
return rsvd_bits(cpuid_maxphyaddr(vcpu), 63);
}

+static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2,
+ int nent)
+{
+ int r;
+
+ r = kvm_check_cpuid(e2, nent);
+ if (r)
+ return r;
+
+ kvfree(vcpu->arch.cpuid_entries);
+ vcpu->arch.cpuid_entries = e2;
+ vcpu->arch.cpuid_nent = nent;
+
+ kvm_update_cpuid_runtime(vcpu);
+ kvm_vcpu_after_set_cpuid(vcpu);
+
+ return 0;
+}
+
/* when an old userspace process fills a new kernel module */
int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
struct kvm_cpuid *cpuid,
@@ -268,18 +287,9 @@ int kvm_vcpu_ioctl_set_cpuid(struct kvm_
e2[i].padding[2] = 0;
}

- r = kvm_check_cpuid(e2, cpuid->nent);
- if (r) {
+ r = kvm_set_cpuid(vcpu, e2, cpuid->nent);
+ if (r)
kvfree(e2);
- goto out_free_cpuid;
- }
-
- kvfree(vcpu->arch.cpuid_entries);
- vcpu->arch.cpuid_entries = e2;
- vcpu->arch.cpuid_nent = cpuid->nent;
-
- kvm_update_cpuid_runtime(vcpu);
- kvm_vcpu_after_set_cpuid(vcpu);

out_free_cpuid:
kvfree(e);
@@ -303,20 +313,11 @@ int kvm_vcpu_ioctl_set_cpuid2(struct kvm
return PTR_ERR(e2);
}

- r = kvm_check_cpuid(e2, cpuid->nent);
- if (r) {
+ r = kvm_set_cpuid(vcpu, e2, cpuid->nent);
+ if (r)
kvfree(e2);
- return r;
- }

- kvfree(vcpu->arch.cpuid_entries);
- vcpu->arch.cpuid_entries = e2;
- vcpu->arch.cpuid_nent = cpuid->nent;
-
- kvm_update_cpuid_runtime(vcpu);
- kvm_vcpu_after_set_cpuid(vcpu);
-
- return 0;
+ return r;
}

int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,