On 30/08/18 10:39, Christoffer Dall wrote:

On Wed, Jul 18, 2018 at 10:18:48AM +0100, Suzuki K Poulose wrote:

quoted

We load the stage2 context of a guest for different operations,
including running the guest and tlb maintenance on behalf of the
guest. As of now only the vttbr is private to the guest, but this
is about to change with IPA per VM. Add a helper to load the stage2
configuration for a VM, which could do the right thing with the
future changes.

Cc: Christoffer Dall <cdall@kernel.org>
Cc: Marc Zyngier <redacted>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
Changes since v2:
  - New patch
---
  arch/arm64/include/asm/kvm_hyp.h | 6 ++++++
  arch/arm64/kvm/hyp/switch.c      | 2 +-
  arch/arm64/kvm/hyp/tlb.c         | 4 ++--
  3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index 384c343..82f9994 100644
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h

@@ -155,5 +155,11 @@ void deactivate_traps_vhe_put(void);
  u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt);
  void __noreturn __hyp_do_panic(unsigned long, ...);
  
+/* Must be called from hyp code running at EL2 */

more importantly than having to run this at EL2, is that it must have
gone through the proper sequence of update_vttbr() and disabling
interrupts to avoid using a stale VMID.

Right, I will update the comment.

Cheers
Suzuki