KVM: arm: introduce kvm_arm_init/setup/clear_debug

This is a precursor for later patches which will need to do more to
setup debug state before entering the hyp.S switch code. The existing
functionality for setting mdcr_el2 has been moved out of hyp.S and now
uses the value kept in vcpu->arch.mdcr_el2.

As the assembler used to previously mask and preserve MDCR_EL2.HPMN I've
had to add a mechanism to save the value of mdcr_el2 as a per-cpu
variable during the initialisation code. The kernel never sets this
number so we are assuming the bootcode has set up the correct value
here.

This also moves the conditional setting of the TDA bit from the hyp code
into the C code which is currently used for the lazy debug register
context switch code.

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

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 1b693cb2d5b2..77151b111d32 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -543,6 +543,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
                         continue;
                 }
 
+                kvm_arm_setup_debug(vcpu);
+
                 /**************************************************************
                  * Enter the guest
                  */
@@ -557,6 +559,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
                  * Back from guest
                  *************************************************************/
 
+                kvm_arm_clear_debug(vcpu);
+
                 /*
                  * We may have taken a host interrupt in HYP mode (ie
                  * while executing the guest). This interrupt is still
@@ -914,6 +918,8 @@ static void cpu_init_hyp_mode(void *dummy)
         vector_ptr = (unsigned long)__kvm_hyp_vector;
 
         __cpu_init_hyp_mode(boot_pgd_ptr, pgd_ptr, hyp_stack_ptr, vector_ptr);
+
+        kvm_arm_init_debug();
 }
 
 static int hyp_init_cpu_notify(struct notifier_block *self,