[PATCH 5.10 091/120] KVM: x86: fix CPUID entries returned by KVM_GET_CPUID2 ioctl

Greg Kroah-Hartman
2021-02-08T17:30:14Z

From: Michael Roth <michael.roth@amd.com>

commit 181f494888d5b178ffda41bed965f187d5e5c432 upstream.

Recent commit 255cbecfe0 modified struct kvm_vcpu_arch to make
'cpuid_entries' a pointer to an array of kvm_cpuid_entry2 entries
rather than embedding the array in the struct. KVM_SET_CPUID and
KVM_SET_CPUID2 were updated accordingly, but KVM_GET_CPUID2 was missed.

As a result, KVM_GET_CPUID2 currently returns random fields from struct
kvm_vcpu_arch to userspace rather than the expected CPUID values. Fix
this by treating 'cpuid_entries' as a pointer when copying its
contents to userspace buffer.

Fixes: 255cbecfe0c9 ("KVM: x86: allocate vcpu->arch.cpuid_entries dynamically")
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Michael Roth <michael.roth@amd.com.com>
Message-Id: <20210128024451.1816770-1-michael.roth@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/cpuid.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -320,7 +320,7 @@ int kvm_vcpu_ioctl_get_cpuid2(struct kvm
if (cpuid->nent < vcpu->arch.cpuid_nent)
goto out;
r = -EFAULT;
- if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
+ if (copy_to_user(entries, vcpu->arch.cpuid_entries,
vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
goto out;
return 0;