[PATCH v8 08/11] KVM: arm64: introduce vcpu->arch.debug_ptr

Alex Bennée
2015-07-07T16:18:52Z

This introduces a level of indirection for the debug registers. Instead
of using the sys_regs[] directly we store registers in a structure in
the vcpu. The new kvm_arm_reset_debug_ptr() sets the debug ptr to the
guest context.

Because we no longer give the sys_regs offset for the sys_reg_desc->reg
field, but instead the index into a debug-specific struct we need to
add a number of additional trap functions for each register. Also as the
generic generic user-space access code no longer works we have
introduced a new pair of function pointers to the sys_reg_desc structure
to override the generic code when needed.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

---
v6:
- fix up some ws issues
- correct clobber info
- re-word commentary in kvm_host.h
- fix endian access issues for aarch32 fields
- revert all KVM_GET/SET_ONE_REG to 64bit (also see ABI update)
v7
- new fn kvm_arm_reset_debug_ptr(), stubbed for arm
- split trap fns into bcr,bvr,bcr,wvr and wxvr
- add set/get fns to sys_regs_desc
- reg_to_dbg/dbg_to_reg helpers for 32bit support
v8
- rm #if 0 left over from re-factor
- re-word reset_ptr comment
- fix inadvertent whitespace changes
- rename get/set to get_user/set_user
- update commit wording
- re-factor dbg_to_reg/reg_to_dbg
- add newlines to keep checkpatch happy
- ensure 63:32 of debug registers untouched by aarch32
---
arch/arm/include/asm/kvm_host.h | 1 +
arch/arm/kvm/arm.c | 2 +
arch/arm64/include/asm/kvm_asm.h | 24 ++--
arch/arm64/include/asm/kvm_host.h | 17 ++-
arch/arm64/kernel/asm-offsets.c | 6 +
arch/arm64/kvm/debug.c | 9 ++
arch/arm64/kvm/hyp.S | 24 ++--
arch/arm64/kvm/sys_regs.c | 274 +++++++++++++++++++++++++++++++++++---
arch/arm64/kvm/sys_regs.h | 6 +
9 files changed, 316 insertions(+), 47 deletions(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 746c0c69..825c337 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -239,5 +239,6 @@ static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
static inline void kvm_arm_init_debug(void) {}
static inline void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) {}
static inline void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) {}
+static inline void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu) {}

#endif /* __ARM_KVM_HOST_H__ */
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index af60e6f..525473f 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -279,6 +279,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
/* Set up the timer */
kvm_timer_vcpu_init(vcpu);

+ kvm_arm_reset_debug_ptr(vcpu);
+
return 0;
}

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index d6b507e..e997404 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -46,24 +46,16 @@
#define CNTKCTL_EL1 20 /* Timer Control Register (EL1) */
#define PAR_EL1 21 /* Physical Address Register */
#define MDSCR_EL1 22 /* Monitor Debug System Control Register */
-#define DBGBCR0_EL1 23 /* Debug Breakpoint Control Registers (0-15) */
-#define DBGBCR15_EL1 38
-#define DBGBVR0_EL1 39 /* Debug Breakpoint Value Registers (0-15) */
-#define DBGBVR15_EL1 54
-#define DBGWCR0_EL1 55 /* Debug Watchpoint Control Registers (0-15) */
-#define DBGWCR15_EL1 70
-#define DBGWVR0_EL1 71 /* Debug Watchpoint Value Registers (0-15) */
-#define DBGWVR15_EL1 86
-#define MDCCINT_EL1 87 /* Monitor Debug Comms Channel Interrupt Enable Reg */
+#define MDCCINT_EL1 23 /* Monitor Debug Comms Channel Interrupt Enable Reg */

/* 32bit specific registers. Keep them at the end of the range */
-#define DACR32_EL2 88 /* Domain Access Control Register */
-#define IFSR32_EL2 89 /* Instruction Fault Status Register */
-#define FPEXC32_EL2 90 /* Floating-Point Exception Control Register */
-#define DBGVCR32_EL2 91 /* Debug Vector Catch Register */
-#define TEECR32_EL1 92 /* ThumbEE Configuration Register */
-#define TEEHBR32_EL1 93 /* ThumbEE Handler Base Register */
-#define NR_SYS_REGS 94
+#define DACR32_EL2 24 /* Domain Access Control Register */
+#define IFSR32_EL2 25 /* Instruction Fault Status Register */
+#define FPEXC32_EL2 26 /* Floating-Point Exception Control Register */
+#define DBGVCR32_EL2 27 /* Debug Vector Catch Register */
+#define TEECR32_EL1 28 /* ThumbEE Configuration Register */
+#define TEEHBR32_EL1 29 /* ThumbEE Handler Base Register */
+#define NR_SYS_REGS 30

/* 32bit mapping */
#define c0_MPIDR (MPIDR_EL1 * 2) /* MultiProcessor ID Register */
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index e2db6a6..461d288 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -108,11 +108,25 @@ struct kvm_vcpu_arch {
/* Exception Information */
struct kvm_vcpu_fault_info fault;

- /* Debug state */
+ /* Guest debug state */
u64 debug_flags;

+ /*
+ * We maintain more than a single set of debug registers to support
+ * debugging the guest from the host and to maintain separate host and
+ * guest state during world switches. vcpu_debug_state are the debug
+ * registers of the vcpu as the guest sees them. host_debug_state are
+ * the host registers which are saved and restored during world switches.
+ *
+ * debug_ptr points to the set of debug registers that should be loaded
+ * onto the hardware when running the guest.
+ */
+ struct kvm_guest_debug_arch *debug_ptr;
+ struct kvm_guest_debug_arch vcpu_debug_state;
+
/* Pointer to host CPU context */
kvm_cpu_context_t *host_cpu_context;
+ struct kvm_guest_debug_arch host_debug_state;

/* VGIC state */
struct vgic_cpu vgic_cpu;
@@ -265,5 +279,6 @@ static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
void kvm_arm_init_debug(void);
void kvm_arm_setup_debug(struct kvm_vcpu *vcpu);
void kvm_arm_clear_debug(struct kvm_vcpu *vcpu);
+void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu);

#endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index dfb25a2..1a8e97c 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -116,10 +116,16 @@ int main(void)
DEFINE(VCPU_FAR_EL2, offsetof(struct kvm_vcpu, arch.fault.far_el2));
DEFINE(VCPU_HPFAR_EL2, offsetof(struct kvm_vcpu, arch.fault.hpfar_el2));
DEFINE(VCPU_DEBUG_FLAGS, offsetof(struct kvm_vcpu, arch.debug_flags));
+ DEFINE(VCPU_DEBUG_PTR, offsetof(struct kvm_vcpu, arch.debug_ptr));
+ DEFINE(DEBUG_BCR, offsetof(struct kvm_guest_debug_arch, dbg_bcr));
+ DEFINE(DEBUG_BVR, offsetof(struct kvm_guest_debug_arch, dbg_bvr));
+ DEFINE(DEBUG_WCR, offsetof(struct kvm_guest_debug_arch, dbg_wcr));
+ DEFINE(DEBUG_WVR, offsetof(struct kvm_guest_debug_arch, dbg_wvr));
DEFINE(VCPU_HCR_EL2, offsetof(struct kvm_vcpu, arch.hcr_el2));
DEFINE(VCPU_MDCR_EL2, offsetof(struct kvm_vcpu, arch.mdcr_el2));
DEFINE(VCPU_IRQ_LINES, offsetof(struct kvm_vcpu, arch.irq_lines));
DEFINE(VCPU_HOST_CONTEXT, offsetof(struct kvm_vcpu, arch.host_cpu_context));
+ DEFINE(VCPU_HOST_DEBUG_STATE, offsetof(struct kvm_vcpu, arch.host_debug_state));
DEFINE(VCPU_TIMER_CNTV_CTL, offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_ctl));
DEFINE(VCPU_TIMER_CNTV_CVAL, offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_cval));
DEFINE(KVM_TIMER_CNTVOFF, offsetof(struct kvm, arch.timer.cntvoff));
diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c
index d439eb8..e0947b7 100644
--- a/arch/arm64/kvm/debug.c
+++ b/arch/arm64/kvm/debug.c
@@ -67,6 +67,15 @@ void kvm_arm_init_debug(void)
}

/**
+ * 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
*
* @vcpu: the vcpu pointer
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 77c08df..f56e93f 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -600,6 +600,7 @@ __restore_sysregs:
/* Save debug state */
__save_debug:
// x2: ptr to CPU context
+ // x3: ptr to debug reg struct
// x4/x5/x6-22/x24-26: trashed

mrs x26, id_aa64dfr0_el1
@@ -610,15 +611,15 @@ __save_debug:
sub w25, w26, w25 // How many WPs to skip

mov x5, x24
- add x4, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
+ add x4, x3, #DEBUG_BCR
save_debug dbgbcr
- add x4, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
+ add x4, x3, #DEBUG_BVR
save_debug dbgbvr

mov x5, x25
- add x4, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
+ add x4, x3, #DEBUG_WCR
save_debug dbgwcr
- add x4, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
+ add x4, x3, #DEBUG_WVR
save_debug dbgwvr

mrs x21, mdccint_el1
@@ -628,6 +629,7 @@ __save_debug:
/* Restore debug state */
__restore_debug:
// x2: ptr to CPU context
+ // x3: ptr to debug reg struct
// x4/x5/x6-22/x24-26: trashed

mrs x26, id_aa64dfr0_el1
@@ -638,15 +640,15 @@ __restore_debug:
sub w25, w26, w25 // How many WPs to skip

mov x5, x24
- add x4, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
+ add x4, x3, #DEBUG_BCR
restore_debug dbgbcr
- add x4, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
+ add x4, x3, #DEBUG_BVR
restore_debug dbgbvr

mov x5, x25
- add x4, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
+ add x4, x3, #DEBUG_WCR
restore_debug dbgwcr
- add x4, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
+ add x4, x3, #DEBUG_WVR
restore_debug dbgwvr

ldr x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)]
@@ -686,6 +688,7 @@ ENTRY(__kvm_vcpu_run)
bl __save_sysregs

compute_debug_state 1f
+ add x3, x0, #VCPU_HOST_DEBUG_STATE
bl __save_debug
1:
activate_traps
@@ -701,6 +704,8 @@ ENTRY(__kvm_vcpu_run)
bl __restore_fpsimd

skip_debug_state x3, 1f
+ ldr x3, [x0, #VCPU_DEBUG_PTR]
+ kern_hyp_va x3
bl __restore_debug
1:
restore_guest_32bit_state
@@ -721,6 +726,8 @@ __kvm_vcpu_return:
bl __save_sysregs

skip_debug_state x3, 1f
+ ldr x3, [x0, #VCPU_DEBUG_PTR]
+ kern_hyp_va x3
bl __save_debug
1:
save_guest_32bit_state
@@ -743,6 +750,7 @@ __kvm_vcpu_return:
// already been saved. Note that we nuke the whole 64bit word.
// If we ever add more flags, we'll have to be more careful...
str xzr, [x0, #VCPU_DEBUG_FLAGS]
+ add x3, x0, #VCPU_HOST_DEBUG_STATE
bl __restore_debug
1:
restore_host_regs
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index c370b40..158bae7 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -211,6 +211,203 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu,
return true;
}

+/*
+ * reg_to_dbg/dbg_to_reg
+ *
+ * A 32 bit write to a debug register leave top bits alone
+ * A 32 bit read from a debug register only returns the bottom bits
+ *
+ * All writes will set the KVM_ARM64_DEBUG_DIRTY flag to ensure the
+ * hyp.S code switches between host and guest values in future.
+ */
+static inline void reg_to_dbg(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *p,
+ u64 *dbg_reg)
+{
+ u64 val = *vcpu_reg(vcpu, p->Rt);
+
+ if (p->is_32bit) {
+ val &= 0xffffffffUL;
+ val |= ((*dbg_reg >> 32) << 32);
+ }
+
+ *dbg_reg = val;
+ vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
+}
+
+static inline void dbg_to_reg(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *p,
+ u64 *dbg_reg)
+{
+ u64 val = *dbg_reg;
+
+ if (p->is_32bit)
+ val &= 0xffffffffUL;
+
+ *vcpu_reg(vcpu, p->Rt) = val;
+}
+
+static inline bool trap_bvr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *p,
+ const struct sys_reg_desc *rd)
+{
+ u64 *dbg_reg = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
+
+ if (p->is_write)
+ reg_to_dbg(vcpu, p, dbg_reg);
+ else
+ dbg_to_reg(vcpu, p, dbg_reg);
+
+ return true;
+}
+
+static int set_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
+
+ if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static int get_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
+
+ if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static inline void reset_bvr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg] = rd->val;
+}
+
+static inline bool trap_bcr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *p,
+ const struct sys_reg_desc *rd)
+{
+ u64 *dbg_reg = &vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg];
+
+ if (p->is_write)
+ reg_to_dbg(vcpu, p, dbg_reg);
+ else
+ dbg_to_reg(vcpu, p, dbg_reg);
+
+ return true;
+}
+
+static int set_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg];
+
+ if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+
+ return 0;
+}
+
+static int get_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg];
+
+ if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static inline void reset_bcr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg] = rd->val;
+}
+
+static inline bool trap_wvr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *p,
+ const struct sys_reg_desc *rd)
+{
+ u64 *dbg_reg = &vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg];
+
+ if (p->is_write)
+ reg_to_dbg(vcpu, p, dbg_reg);
+ else
+ dbg_to_reg(vcpu, p, dbg_reg);
+
+ return true;
+}
+
+static int set_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg];
+
+ if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static int get_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg];
+
+ if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static inline void reset_wvr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg] = rd->val;
+}
+
+static inline bool trap_wcr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *p,
+ const struct sys_reg_desc *rd)
+{
+ u64 *dbg_reg = &vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg];
+
+ if (p->is_write)
+ reg_to_dbg(vcpu, p, dbg_reg);
+ else
+ dbg_to_reg(vcpu, p, dbg_reg);
+
+ return true;
+}
+
+static int set_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg];
+
+ if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static int get_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg];
+
+ if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static inline void reset_wcr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg] = rd->val;
+}
+
static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
u64 amair;
@@ -240,16 +437,16 @@ static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
#define DBG_BCR_BVR_WCR_WVR_EL1(n) \
/* DBGBVRn_EL1 */ \
{ Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b100), \
- trap_debug_regs, reset_val, (DBGBVR0_EL1 + (n)), 0 }, \
+ trap_bvr, reset_bvr, n, 0, get_bvr, set_bvr }, \
/* DBGBCRn_EL1 */ \
{ Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b101), \
- trap_debug_regs, reset_val, (DBGBCR0_EL1 + (n)), 0 }, \
+ trap_bcr, reset_bcr, n, 0, get_bcr, set_bcr }, \
/* DBGWVRn_EL1 */ \
{ Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b110), \
- trap_debug_regs, reset_val, (DBGWVR0_EL1 + (n)), 0 }, \
+ trap_wvr, reset_wvr, n, 0, get_wvr, set_wvr }, \
/* DBGWCRn_EL1 */ \
{ Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b111), \
- trap_debug_regs, reset_val, (DBGWCR0_EL1 + (n)), 0 }
+ trap_wcr, reset_wcr, n, 0, get_wcr, set_wcr }

/*
* Architected system registers.
@@ -516,28 +713,55 @@ static bool trap_debug32(struct kvm_vcpu *vcpu,
return true;
}

-#define DBG_BCR_BVR_WCR_WVR(n) \
- /* DBGBVRn */ \
- { Op1( 0), CRn( 0), CRm((n)), Op2( 4), trap_debug32, \
- NULL, (cp14_DBGBVR0 + (n) * 2) }, \
- /* DBGBCRn */ \
- { Op1( 0), CRn( 0), CRm((n)), Op2( 5), trap_debug32, \
- NULL, (cp14_DBGBCR0 + (n) * 2) }, \
- /* DBGWVRn */ \
- { Op1( 0), CRn( 0), CRm((n)), Op2( 6), trap_debug32, \
- NULL, (cp14_DBGWVR0 + (n) * 2) }, \
- /* DBGWCRn */ \
- { Op1( 0), CRn( 0), CRm((n)), Op2( 7), trap_debug32, \
- NULL, (cp14_DBGWCR0 + (n) * 2) }
-
-#define DBGBXVR(n) \
- { Op1( 0), CRn( 1), CRm((n)), Op2( 1), trap_debug32, \
- NULL, cp14_DBGBXVR0 + n * 2 }
+/* AArch32 debug register mappings
+ *
+ * AArch32 DBGBVRn is mapped to DBGBVRn_EL1[31:0]
+ * AArch32 DBGBXVRn is mapped to DBGBVRn_EL1[63:32]
+ *
+ * All control registers and watchpoint value registers are mapped to
+ * the lower 32 bits of their AArch64 equivalents. We share the trap
+ * handlers with the above AArch64 code which checks what mode the
+ * system is in.
+ */
+
+static inline bool trap_xvr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *p,
+ const struct sys_reg_desc *rd)
+{
+ u64 *dbg_reg = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
+
+ if (p->is_write) {
+ u64 val = *dbg_reg;
+
+ val &= 0xffffffffUL;
+ val |= *vcpu_reg(vcpu, p->Rt) << 32;
+ *dbg_reg = val;
+
+ vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
+ } else {
+ *vcpu_reg(vcpu, p->Rt) = *dbg_reg >> 32;
+ }
+
+ return true;
+}
+
+#define DBG_BCR_BVR_WCR_WVR(n) \
+ /* DBGBVRn */ \
+ { Op1( 0), CRn( 0), CRm((n)), Op2( 4), trap_bvr, NULL, n }, \
+ /* DBGBCRn */ \
+ { Op1( 0), CRn( 0), CRm((n)), Op2( 5), trap_bcr, NULL, n }, \
+ /* DBGWVRn */ \
+ { Op1( 0), CRn( 0), CRm((n)), Op2( 6), trap_wvr, NULL, n }, \
+ /* DBGWCRn */ \
+ { Op1( 0), CRn( 0), CRm((n)), Op2( 7), trap_wcr, NULL, n }
+
+#define DBGBXVR(n) \
+ { Op1( 0), CRn( 1), CRm((n)), Op2( 1), trap_xvr, NULL, n }

/*
* Trapped cp14 registers. We generally ignore most of the external
* debug, on the principle that they don't really make sense to a
- * guest. Revisit this one day, whould this principle change.
+ * guest. Revisit this one day, would this principle change.
*/
static const struct sys_reg_desc cp14_regs[] = {
/* DBGIDR */
@@ -1303,6 +1527,9 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
if (!r)
return get_invariant_sys_reg(reg->id, uaddr);

+ if (r->get_user)
+ return (r->get_user)(vcpu, r, reg, uaddr);
+
return reg_to_user(uaddr, &vcpu_sys_reg(vcpu, r->reg), reg->id);
}

@@ -1321,6 +1548,9 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
if (!r)
return set_invariant_sys_reg(reg->id, uaddr);

+ if (r->set_user)
+ return (r->set_user)(vcpu, r, reg, uaddr);
+
return reg_from_user(&vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
}

diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index d411e25..eaa324e 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -55,6 +55,12 @@ struct sys_reg_desc {

/* Value (usually reset value) */
u64 val;
+
+ /* Custom get/set_user functions, fallback to generic if NULL */
+ int (*get_user)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr);
+ int (*set_user)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr);
};

static inline void print_sys_reg_instr(const struct sys_reg_params *p)