kvm: x86: default legacy PCI device assignment support to "n"

VFIO has proved itself a much better option than KVM's built-in
device assignment.  It is mature, provides better isolation because
it enforces ACS, and even the userspace code is being tested on
a wider variety of hardware these days than the legacy support.

Disable legacy device assignment by default.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 413a7bf9efbb93286aa6d3de429f4efcef5c3887..a0f06a5947c5f086294186cb584090ca2c6a8cdc 100644 (file)
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -88,13 +88,14 @@ config KVM_MMU_AUDIT
 config KVM_DEVICE_ASSIGNMENT
        bool "KVM legacy PCI device assignment support"
        depends on KVM && PCI && IOMMU_API
-       default y
+       default n
        ---help---
          Provide support for legacy PCI device assignment through KVM.  The
          kernel now also supports a full featured userspace device driver
-         framework through VFIO, which supersedes much of this support.
+         framework through VFIO, which supersedes this support and provides
+         better security.
 
-         If unsure, say Y.
+         If unsure, say N.
 
 # OK, it's a little counter-intuitive to do this, but it puts it neatly under
 # the virtualization menu.