[PATCH v4 03/12] KVM: arm64: guest debug, define API headers

["Alex Bennée" <alex.bennee@linaro.org>]

This commit defines the API headers for guest debugging. There are two
architecture specific debug structures:

  - kvm_guest_debug_arch, allows us to pass in HW debug registers
  - kvm_debug_exit_arch, signals exception and possible faulting address

The type of debugging being used is controlled by the architecture
specific control bits of the kvm_guest_debug->control flags in the ioctl
structure.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>

---
v2
   - expose hsr and pc directly to user-space
v3
   - s/control/controlled/ in commit message
   - add v8 to ARM ARM comment (ARM Architecture Reference Manual)
   - add rb tag
   - rm pc, add far
   - re-word comments on alignment
   - rename KVM_ARM_NDBG_REGS -> KVM_ARM_MAX_DBG_REGS
v4
   - now uses common HW/SW BP define
   - add a-b-tag
   - use u32 for control regs

diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index d268320..8796610 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -100,10 +100,28 @@ struct kvm_sregs {
 struct kvm_fpu {
 };
 
+/*
+ * See v8 ARM ARM D7.3: Debug Registers
+ *
+ * The control registers are architecturally defined as 32 bits but are
+ * stored as 64 bit values alongside the value registers. This is done
+ * to keep the copying of these values into the vcpu context simple as
+ * everything is 64 bit aligned (see DBGBCR0_EL1 onwards in kvm_asm.h).
+ *
+ * The architectural limit is 16 debug registers of each type although
+ * in practice there are usually less (see ID_AA64DFR0_EL1).
+ */
+#define KVM_ARM_MAX_DBG_REGS 16
 struct kvm_guest_debug_arch {
+	__u32 dbg_bcr[KVM_ARM_MAX_DBG_REGS];
+	__u64 dbg_bvr[KVM_ARM_MAX_DBG_REGS];
+	__u32 dbg_wcr[KVM_ARM_MAX_DBG_REGS];
+	__u64 dbg_wvr[KVM_ARM_MAX_DBG_REGS];
 };
 
 struct kvm_debug_exit_arch {
+	__u32 hsr;
+	__u64 far;
 };
 
 struct kvm_sync_regs {
-- 
2.3.5

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