KVM: arm/arm64: VGIC/ITS: protect kvm_read_guest() calls with SRCU lock
authorAndre Przywara <andre.przywara@arm.com>
Fri, 11 May 2018 14:20:14 +0000 (15:20 +0100)
committerPaolo Bonzini <pbonzini@redhat.com>
Tue, 15 May 2018 11:36:49 +0000 (13:36 +0200)
commitbf308242ab98b5d1648c3663e753556bef9bec01
treee01104e8d59a2199b011772e943c32f029a21982
parent9c4188762f7fee032abf8451fd9865a9abfc5516
KVM: arm/arm64: VGIC/ITS: protect kvm_read_guest() calls with SRCU lock

kvm_read_guest() will eventually look up in kvm_memslots(), which requires
either to hold the kvm->slots_lock or to be inside a kvm->srcu critical
section.
In contrast to x86 and s390 we don't take the SRCU lock on every guest
exit, so we have to do it individually for each kvm_read_guest() call.

Provide a wrapper which does that and use that everywhere.

Note that ending the SRCU critical section before returning from the
kvm_read_guest() wrapper is safe, because the data has been *copied*, so
we don't need to rely on valid references to the memslot anymore.

Cc: Stable <stable@vger.kernel.org> # 4.8+
Reported-by: Jan Glauber <jan.glauber@caviumnetworks.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
arch/arm/include/asm/kvm_mmu.h
arch/arm64/include/asm/kvm_mmu.h
virt/kvm/arm/vgic/vgic-its.c