[PATCH v2 9/9] arm64: KVM: enable trapping of all debug registers

Marc Zyngier
2014-05-20T16:56:01Z

Enable trapping of the debug registers, preventing the guests to
mess with the host state (and allowing guests to use the debug
infrastructure as well).

Reviewed-by: Anup Patel <anup.patel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/kvm/hyp.S | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 73ec5c4..72ed0bf8 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -777,6 +777,14 @@ __kvm_hyp_code_start:
mrs x2, mdcr_el2
and x2, x2, #MDCR_EL2_HPMN_MASK
orr x2, x2, #(MDCR_EL2_TPM | MDCR_EL2_TPMCR)
+ orr x2, x2, #(MDCR_EL2_TDRA | MDCR_EL2_TDOSA)
+
+ // Check for KVM_ARM64_DEBUG_DIRTY, and set to debug to trap
+ // if not dirty.
+ ldr x3, [x0, #VCPU_DEBUG_FLAGS]
+ tbnz x3, #KVM_ARM64_DEBUG_DIRTY_SHIFT, 1f
+ orr x2, x2, #MDCR_EL2_TDA
+1:
msr mdcr_el2, x2
.endm

--
1.8.3.4