KVM: x86: allocate vcpu->arch.cpuid_entries dynamically
The current limit for guest CPUID leaves (KVM_MAX_CPUID_ENTRIES, 80)
is reported to be insufficient but before we bump it let's switch to
allocating vcpu->arch.cpuid_entries[] array dynamically. Currently,
'struct kvm_cpuid_entry2' is 40 bytes so vcpu->arch.cpuid_entries is
3200 bytes which accounts for 1/4 of the whole 'struct kvm_vcpu_arch'
but having it pre-allocated (for all vCPUs which we also pre-allocate)
gives us no real benefits.
Another plus of the dynamic allocation is that we now do kvm_check_cpuid()
check before we assign anything to vcpu->arch.cpuid_nent/cpuid_entries so
no changes are made in case the check fails.
Opportunistically remove unneeded 'out' labels from
kvm_vcpu_ioctl_set_cpuid()/kvm_vcpu_ioctl_set_cpuid2() and return
directly whenever possible.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20201001130541.1398392-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ca940de..92f8500 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9948,6 +9948,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
kvm_mmu_destroy(vcpu);
srcu_read_unlock(&vcpu->kvm->srcu, idx);
free_page((unsigned long)vcpu->arch.pio_data);
+ kvfree(vcpu->arch.cpuid_entries);
if (!lapic_in_kernel(vcpu))
static_key_slow_dec(&kvm_no_apic_vcpu);
}