path: root/virt
diff options
authorJames Morse <james.morse@arm.com>2018-01-15 19:39:00 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2018-01-16 15:08:24 +0000
commit4f5abad9e826bd579b0661efa32682d9c9bc3fa8 (patch)
tree8a89f5b9098b8cd411753d7bced1733cddef5fc7 /virt
parent68ddbf09ec5a888ec850edd7e7438d2daf069c56 (diff)
KVM: arm/arm64: mask/unmask daif around VHE guests
Non-VHE systems take an exception to EL2 in order to world-switch into the guest. When returning from the guest KVM implicitly restores the DAIF flags when it returns to the kernel at EL1. With VHE none of this exception-level jumping happens, so KVMs world-switch code is exposed to the host kernel's DAIF values, and KVM spills the guest-exit DAIF values back into the host kernel. On entry to a guest we have Debug and SError exceptions unmasked, KVM has switched VBAR but isn't prepared to handle these. On guest exit Debug exceptions are left disabled once we return to the host and will stay this way until we enter user space. Add a helper to mask/unmask DAIF around VHE guests. The unmask can only happen after the hosts VBAR value has been synchronised by the isb in __vhe_hyp_call (via kvm_call_hyp()). Masking could be as late as setting KVMs VBAR value, but is kept here for symmetry. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'virt')
1 files changed, 4 insertions, 0 deletions
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index 2fc6009a766c..38e81631fc91 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -704,9 +704,13 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
+ if (has_vhe())
+ kvm_arm_vhe_guest_enter();
ret = kvm_call_hyp(__kvm_vcpu_run, vcpu);
+ if (has_vhe())
+ kvm_arm_vhe_guest_exit();
vcpu->mode = OUTSIDE_GUEST_MODE;