*/
#include <linux/kvm_host.h>
+#include <linux/hw_breakpoint.h>
+#include <asm/debug-monitors.h>
+#include <asm/kvm_asm.h>
#include <asm/kvm_arm.h>
+#include <asm/kvm_emulate.h>
+
+#include "trace.h"
+
+/* These are the bits of MDSCR_EL1 we may manipulate */
+#define MDSCR_EL1_DEBUG_MASK (DBG_MDSCR_SS | \
+ DBG_MDSCR_KDE | \
+ DBG_MDSCR_MDE)
static DEFINE_PER_CPU(u32, mdcr_el2);
+/**
+ * save/restore_guest_debug_regs
+ *
+ * For some debug operations we need to tweak some guest registers. As
+ * a result we need to save the state of those registers before we
+ * make those modifications.
+ *
+ * Guest access to MDSCR_EL1 is trapped by the hypervisor and handled
+ * after we have restored the preserved value to the main context.
+ */
+static void save_guest_debug_regs(struct kvm_vcpu *vcpu)
+{
+ vcpu->arch.guest_debug_preserved.mdscr_el1 = vcpu_sys_reg(vcpu, MDSCR_EL1);
+
+ trace_kvm_arm_set_dreg32("Saved MDSCR_EL1",
+ vcpu->arch.guest_debug_preserved.mdscr_el1);
+}
+
+static void restore_guest_debug_regs(struct kvm_vcpu *vcpu)
+{
+ vcpu_sys_reg(vcpu, MDSCR_EL1) = vcpu->arch.guest_debug_preserved.mdscr_el1;
+
+ trace_kvm_arm_set_dreg32("Restored MDSCR_EL1",
+ vcpu_sys_reg(vcpu, MDSCR_EL1));
+}
+
/**
* kvm_arm_init_debug - grab what we need for debug
*
__this_cpu_write(mdcr_el2, kvm_call_hyp(__kvm_get_mdcr_el2));
}
+/**
+ * kvm_arm_reset_debug_ptr - reset the debug ptr to point to the vcpu state
+ */
+
+void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu)
+{
+ vcpu->arch.debug_ptr = &vcpu->arch.vcpu_debug_state;
+}
/**
* kvm_arm_setup_debug - set up debug related stuff
{
bool trap_debug = !(vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY);
+ trace_kvm_arm_setup_debug(vcpu, vcpu->guest_debug);
+
vcpu->arch.mdcr_el2 = __this_cpu_read(mdcr_el2) & MDCR_EL2_HPMN_MASK;
vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM |
MDCR_EL2_TPMCR |
MDCR_EL2_TDRA |
MDCR_EL2_TDOSA);
- /* Trap on access to debug registers? */
+ /* Is Guest debugging in effect? */
+ if (vcpu->guest_debug) {
+ /* Route all software debug exceptions to EL2 */
+ vcpu->arch.mdcr_el2 |= MDCR_EL2_TDE;
+
+ /* Save guest debug state */
+ save_guest_debug_regs(vcpu);
+
+ /*
+ * Single Step (ARM ARM D2.12.3 The software step state
+ * machine)
+ *
+ * If we are doing Single Step we need to manipulate
+ * the guest's MDSCR_EL1.SS and PSTATE.SS. Once the
+ * step has occurred the hypervisor will trap the
+ * debug exception and we return to userspace.
+ *
+ * If the guest attempts to single step its userspace
+ * we would have to deal with a trapped exception
+ * while in the guest kernel. Because this would be
+ * hard to unwind we suppress the guest's ability to
+ * do so by masking MDSCR_EL.SS.
+ *
+ * This confuses guest debuggers which use
+ * single-step behind the scenes but everything
+ * returns to normal once the host is no longer
+ * debugging the system.
+ */
+ if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {
+ *vcpu_cpsr(vcpu) |= DBG_SPSR_SS;
+ vcpu_sys_reg(vcpu, MDSCR_EL1) |= DBG_MDSCR_SS;
+ } else {
+ vcpu_sys_reg(vcpu, MDSCR_EL1) &= ~DBG_MDSCR_SS;
+ }
+
+ trace_kvm_arm_set_dreg32("SPSR_EL2", *vcpu_cpsr(vcpu));
+
+ /*
+ * HW Breakpoints and watchpoints
+ *
+ * We simply switch the debug_ptr to point to our new
+ * external_debug_state which has been populated by the
+ * debug ioctl. The existing KVM_ARM64_DEBUG_DIRTY
+ * mechanism ensures the registers are updated on the
+ * world switch.
+ */
+ if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW) {
+ /* Enable breakpoints/watchpoints */
+ vcpu_sys_reg(vcpu, MDSCR_EL1) |= DBG_MDSCR_MDE;
+
+ vcpu->arch.debug_ptr = &vcpu->arch.external_debug_state;
+ vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
+ trap_debug = true;
+
+ trace_kvm_arm_set_regset("BKPTS", get_num_brps(),
+ &vcpu->arch.debug_ptr->dbg_bcr[0],
+ &vcpu->arch.debug_ptr->dbg_bvr[0]);
+
+ trace_kvm_arm_set_regset("WAPTS", get_num_wrps(),
+ &vcpu->arch.debug_ptr->dbg_wcr[0],
+ &vcpu->arch.debug_ptr->dbg_wvr[0]);
+ }
+ }
+
+ BUG_ON(!vcpu->guest_debug &&
+ vcpu->arch.debug_ptr != &vcpu->arch.vcpu_debug_state);
+
+ /* Trap debug register access */
if (trap_debug)
vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA;
- /* Trap breakpoints? */
- if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP)
- vcpu->arch.mdcr_el2 |= MDCR_EL2_TDE;
+ trace_kvm_arm_set_dreg32("MDCR_EL2", vcpu->arch.mdcr_el2);
+ trace_kvm_arm_set_dreg32("MDSCR_EL1", vcpu_sys_reg(vcpu, MDSCR_EL1));
}
void kvm_arm_clear_debug(struct kvm_vcpu *vcpu)
{
- /* Nothing to do yet */
+ trace_kvm_arm_clear_debug(vcpu->guest_debug);
+
+ if (vcpu->guest_debug) {
+ restore_guest_debug_regs(vcpu);
+
+ /*
+ * If we were using HW debug we need to restore the
+ * debug_ptr to the guest debug state.
+ */
+ if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW) {
+ kvm_arm_reset_debug_ptr(vcpu);
+
+ trace_kvm_arm_set_regset("BKPTS", get_num_brps(),
+ &vcpu->arch.debug_ptr->dbg_bcr[0],
+ &vcpu->arch.debug_ptr->dbg_bvr[0]);
+
+ trace_kvm_arm_set_regset("WAPTS", get_num_wrps(),
+ &vcpu->arch.debug_ptr->dbg_wcr[0],
+ &vcpu->arch.debug_ptr->dbg_wvr[0]);
+ }
+ }
}
projects / karo-tx-linux.git / blobdiff