From: Marc Zyngier <marc.zyngier@arm.com>
Date: Thu, 24 Apr 2014 09:32:03 +0000 (+0100)
Subject: arm64: KVM: enable trapping of all debug registers
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=d329de09333aeee127aaf22eb7cee9c2dc4cf475;p=deliverable%2Flinux.git

arm64: KVM: enable trapping of all debug registers

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>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---

diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 100494b5c7d4..b72aa9f9215c 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -770,6 +770,14 @@
 	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 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