Re: [PATCH v5 09/12] KVM: arm64: introduce vcpu->arch.debug_ptr
From: Christoffer Dall
Date: Thu Jun 04 2015 - 06:56:10 EST
On Fri, May 29, 2015 at 10:30:25AM +0100, Alex Bennée wrote:
> 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. As we are no longer tied to the layout of the sys_regs[] we
> can make the copies size appropriate for control and value registers.
>
> This also entails updating the sys_regs code to access this new
> structure. Instead of passing a register index we now pass an offset
> into the kvm_guest_debug_arch structure.
>
> We also need to ensure the GET/SET_ONE_REG ioctl operations store the
> registers in their correct location.
>
> Signed-off-by: Alex Bennée <alex.bennee@xxxxxxxxxx>
> ---
> arch/arm/kvm/arm.c | 3 +
> arch/arm64/include/asm/kvm_asm.h | 24 +++-----
> arch/arm64/include/asm/kvm_host.h | 12 +++-
> arch/arm64/kernel/asm-offsets.c | 6 ++
> arch/arm64/kvm/hyp.S | 107 +++++++++++++++++---------------
> arch/arm64/kvm/sys_regs.c | 126 +++++++++++++++++++++++++++++++-------
> 6 files changed, 188 insertions(+), 90 deletions(-)
>
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index 9b3ed6d..0d17c7b 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -279,6 +279,9 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
> /* Set up the timer */
> kvm_timer_vcpu_init(vcpu);
>
> + /* Set the debug registers to be the guests */
> + vcpu->arch.debug_ptr = &vcpu->arch.vcpu_debug_state;
> +
> 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..e5040b6 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -108,11 +108,21 @@ struct kvm_vcpu_arch {
> /* Exception Information */
> struct kvm_vcpu_fault_info fault;
>
> - /* Debug state */
> + /* Guest debug state */
> u64 debug_flags;
>
> + /*
> + * For debugging the guest we need to keep a set of debug
> + * registers which can override the guests own debug state
the guest's
> + * while being used. These are set via the KVM_SET_GUEST_DEBUG
> + * ioctl.
Which ones are set via the KVM_SET_GUEST_DEBUG ioctl?
This comment doesn't feel like it's properly explaining the fields
below, because it feels like there's missing a set of registers for this
to add up. I would suggest rewording this comment to something like:
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.
That is, assuming I got this right.
> + */
> + 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;
> 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/hyp.S b/arch/arm64/kvm/hyp.S
> index 9c4897d..1940a4c 100644
> --- a/arch/arm64/kvm/hyp.S
> +++ b/arch/arm64/kvm/hyp.S
> @@ -228,7 +228,7 @@
> stp x24, x25, [x3, #160]
> .endm
>
> -.macro save_debug type
> +.macro save_debug type regsz offsz
> // x4: pointer to register set
> // x5: number of registers to skip
> // x6..x22 trashed
> @@ -258,22 +258,22 @@
> add x22, x22, x5, lsl #2
> br x22
> 1:
> - str x21, [x4, #(15 * 8)]
> - str x20, [x4, #(14 * 8)]
> - str x19, [x4, #(13 * 8)]
> - str x18, [x4, #(12 * 8)]
> - str x17, [x4, #(11 * 8)]
> - str x16, [x4, #(10 * 8)]
> - str x15, [x4, #(9 * 8)]
> - str x14, [x4, #(8 * 8)]
> - str x13, [x4, #(7 * 8)]
> - str x12, [x4, #(6 * 8)]
> - str x11, [x4, #(5 * 8)]
> - str x10, [x4, #(4 * 8)]
> - str x9, [x4, #(3 * 8)]
> - str x8, [x4, #(2 * 8)]
> - str x7, [x4, #(1 * 8)]
> - str x6, [x4, #(0 * 8)]
> + str \regsz\()21, [x4, #(15 * \offsz)]
> + str \regsz\()20, [x4, #(14 * \offsz)]
> + str \regsz\()19, [x4, #(13 * \offsz)]
> + str \regsz\()18, [x4, #(12 * \offsz)]
> + str \regsz\()17, [x4, #(11 * \offsz)]
> + str \regsz\()16, [x4, #(10 * \offsz)]
> + str \regsz\()15, [x4, #(9 * \offsz)]
> + str \regsz\()14, [x4, #(8 * \offsz)]
> + str \regsz\()13, [x4, #(7 * \offsz)]
> + str \regsz\()12, [x4, #(6 * \offsz)]
> + str \regsz\()11, [x4, #(5 * \offsz)]
> + str \regsz\()10, [x4, #(4 * \offsz)]
> + str \regsz\()9, [x4, #(3 * \offsz)]
> + str \regsz\()8, [x4, #(2 * \offsz)]
> + str \regsz\()7, [x4, #(1 * \offsz)]
> + str \regsz\()6, [x4, #(0 * \offsz)]
> .endm
>
> .macro restore_sysregs
> @@ -318,7 +318,7 @@
> msr mdscr_el1, x25
> .endm
>
> -.macro restore_debug type
> +.macro restore_debug type regsz offsz
> // x4: pointer to register set
> // x5: number of registers to skip
> // x6..x22 trashed
> @@ -327,22 +327,22 @@
> add x22, x22, x5, lsl #2
> br x22
> 1:
> - ldr x21, [x4, #(15 * 8)]
> - ldr x20, [x4, #(14 * 8)]
> - ldr x19, [x4, #(13 * 8)]
> - ldr x18, [x4, #(12 * 8)]
> - ldr x17, [x4, #(11 * 8)]
> - ldr x16, [x4, #(10 * 8)]
> - ldr x15, [x4, #(9 * 8)]
> - ldr x14, [x4, #(8 * 8)]
> - ldr x13, [x4, #(7 * 8)]
> - ldr x12, [x4, #(6 * 8)]
> - ldr x11, [x4, #(5 * 8)]
> - ldr x10, [x4, #(4 * 8)]
> - ldr x9, [x4, #(3 * 8)]
> - ldr x8, [x4, #(2 * 8)]
> - ldr x7, [x4, #(1 * 8)]
> - ldr x6, [x4, #(0 * 8)]
> + ldr \regsz\()21, [x4, #(15 * \offsz)]
> + ldr \regsz\()20, [x4, #(14 * \offsz)]
> + ldr \regsz\()19, [x4, #(13 * \offsz)]
> + ldr \regsz\()18, [x4, #(12 * \offsz)]
> + ldr \regsz\()17, [x4, #(11 * \offsz)]
> + ldr \regsz\()16, [x4, #(10 * \offsz)]
> + ldr \regsz\()15, [x4, #(9 * \offsz)]
> + ldr \regsz\()14, [x4, #(8 * \offsz)]
> + ldr \regsz\()13, [x4, #(7 * \offsz)]
> + ldr \regsz\()12, [x4, #(6 * \offsz)]
> + ldr \regsz\()11, [x4, #(5 * \offsz)]
> + ldr \regsz\()10, [x4, #(4 * \offsz)]
> + ldr \regsz\()9, [x4, #(3 * \offsz)]
> + ldr \regsz\()8, [x4, #(2 * \offsz)]
> + ldr \regsz\()7, [x4, #(1 * \offsz)]
> + ldr \regsz\()6, [x4, #(0 * \offsz)]
>
> adr x22, 1f
> add x22, x22, x5, lsl #2
> @@ -601,6 +601,7 @@ __restore_sysregs:
> __save_debug:
> // x0: base address for vcpu context
> // x2: ptr to current CPU context
> + // x3: ptr to debug reg struct
> // x4/x5: trashed
>
> mrs x26, id_aa64dfr0_el1
> @@ -611,16 +612,16 @@ __save_debug:
> sub w25, w26, w25 // How many WPs to skip
>
> mov x5, x24
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
> - save_debug dbgbcr
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
> - save_debug dbgbvr
> + add x4, x3, #DEBUG_BCR
> + save_debug dbgbcr w 4
> + add x4, x3, #DEBUG_BVR
> + save_debug dbgbvr x 8
>
> mov x5, x25
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
> - save_debug dbgwcr
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
> - save_debug dbgwvr
> + add x4, x3, #DEBUG_WCR
> + save_debug dbgwcr w 4
> + add x4, x3, #DEBUG_WVR
> + save_debug dbgwvr x 8
>
> mrs x21, mdccint_el1
> str x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)]
> @@ -640,16 +641,16 @@ __restore_debug:
> sub w25, w26, w25 // How many WPs to skip
>
> mov x5, x24
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
> - restore_debug dbgbcr
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
> - restore_debug dbgbvr
> + add x4, x3, #DEBUG_BCR
> + restore_debug dbgbcr w 4
> + add x4, x3, #DEBUG_BVR
> + restore_debug dbgbvr x 8
>
> mov x5, x25
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
> - restore_debug dbgwcr
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
> - restore_debug dbgwvr
> + add x4, x3, #DEBUG_WCR
> + restore_debug dbgwcr w 4
> + add x4, x3, #DEBUG_WVR
> + restore_debug dbgwvr x 8
>
> ldr x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)]
> msr mdccint_el1, x21
> @@ -688,6 +689,7 @@ ENTRY(__kvm_vcpu_run)
> bl __save_sysregs
>
> compute_debug_state 1f
> + add x3, x0, #VCPU_HOST_DEBUG_STATE
> bl __save_debug
> 1:
> activate_traps
> @@ -703,6 +705,8 @@ 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
> @@ -723,6 +727,8 @@ __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
> @@ -745,6 +751,7 @@ __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..405403e 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -211,6 +211,48 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu,
> return true;
> }
>
> +static inline bool trap_debug32(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p,
> + const struct sys_reg_desc *rd)
> +{
> + __u32 *r = (__u32 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
Does this work on BE systems?
> + if (p->is_write) {
> + *r = *vcpu_reg(vcpu, p->Rt);
> + vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
> + } else {
> + *vcpu_reg(vcpu, p->Rt) = *r;
> + }
> +
> + return true;
> +}
> +
> +static inline bool trap_debug64(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p,
> + const struct sys_reg_desc *rd)
> +{
> + __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
> + if (p->is_write) {
> + *r = *vcpu_reg(vcpu, p->Rt);
> + vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
> + } else {
> + *vcpu_reg(vcpu, p->Rt) = *r;
> + }
> +
> + return true;
> +}
> +
> +static inline void reset_debug32(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd)
> +{
> + __u32 *r = (__u32 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
Does this work on BE systems?
> + *r = rd->val;
> +}
> +
> +static inline void reset_debug64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd)
> +{
> + __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
> + *r = rd->val;
> +}
> +
> static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> u64 amair;
> @@ -240,16 +282,20 @@ 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_debug64, reset_debug64, \
> + offsetof(struct kvm_guest_debug_arch, dbg_bvr[(n)]), 0 }, \
> /* DBGBCRn_EL1 */ \
> { Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b101), \
> - trap_debug_regs, reset_val, (DBGBCR0_EL1 + (n)), 0 }, \
> + trap_debug32, reset_debug32, \
> + offsetof(struct kvm_guest_debug_arch, dbg_bcr[(n)]), 0}, \
> /* DBGWVRn_EL1 */ \
> { Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b110), \
> - trap_debug_regs, reset_val, (DBGWVR0_EL1 + (n)), 0 }, \
> + trap_debug64, reset_debug64, \
> + offsetof(struct kvm_guest_debug_arch, dbg_wvr[(n)]), 0 }, \
> /* DBGWCRn_EL1 */ \
> { Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b111), \
> - trap_debug_regs, reset_val, (DBGWCR0_EL1 + (n)), 0 }
> + trap_debug32, reset_debug32, \
> + offsetof(struct kvm_guest_debug_arch, dbg_wcr[(n)]), 0}
>
> /*
> * Architected system registers.
> @@ -502,37 +548,23 @@ static bool trap_dbgidr(struct kvm_vcpu *vcpu,
> }
> }
>
> -static bool trap_debug32(struct kvm_vcpu *vcpu,
> - const struct sys_reg_params *p,
> - const struct sys_reg_desc *r)
> -{
> - if (p->is_write) {
> - vcpu_cp14(vcpu, r->reg) = *vcpu_reg(vcpu, p->Rt);
> - vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
> - } else {
> - *vcpu_reg(vcpu, p->Rt) = vcpu_cp14(vcpu, r->reg);
> - }
> -
> - 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) }, \
> + NULL, offsetof(struct kvm_guest_debug_arch, dbg_bvr[(n)]) }, \
> /* DBGBCRn */ \
> { Op1( 0), CRn( 0), CRm((n)), Op2( 5), trap_debug32, \
> - NULL, (cp14_DBGBCR0 + (n) * 2) }, \
> + NULL, offsetof(struct kvm_guest_debug_arch, dbg_bcr[(n)]) }, \
> /* DBGWVRn */ \
> { Op1( 0), CRn( 0), CRm((n)), Op2( 6), trap_debug32, \
> - NULL, (cp14_DBGWVR0 + (n) * 2) }, \
> + NULL, offsetof(struct kvm_guest_debug_arch, dbg_wvr[(n)]) }, \
> /* DBGWCRn */ \
> { Op1( 0), CRn( 0), CRm((n)), Op2( 7), trap_debug32, \
> - NULL, (cp14_DBGWCR0 + (n) * 2) }
> + NULL, offsetof(struct kvm_guest_debug_arch, dbg_wcr[(n)]) }
>
> #define DBGBXVR(n) \
> { Op1( 0), CRn( 1), CRm((n)), Op2( 1), trap_debug32, \
> - NULL, cp14_DBGBXVR0 + n * 2 }
> + NULL, offsetof(struct kvm_guest_debug_arch, dbg_bvr[(n)])+sizeof(__u32) }
Does this work on BE systems?
>
> /*
> * Trapped cp14 registers. We generally ignore most of the external
> @@ -1288,6 +1320,42 @@ static int demux_c15_set(u64 id, void __user *uaddr)
> }
> }
>
> +static int debug_set32(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u32 *r = (__u32 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
Does this work on BE systems?
> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
don't you risk copying beyond the boundaries of the array elements here
because KVM_REG_SIZE() is always 64 bits?
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int debug_set64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int debug_get32(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u32 *r = (__u32 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
Does this work on BE systems?
> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
don't you risk reading beyond the boundaries of the array elements here
because KVM_REG_SIZE() is always 64 bits?
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int debug_get64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
> {
> const struct sys_reg_desc *r;
> @@ -1303,6 +1371,12 @@ 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->access == trap_debug64)
> + return debug_get64(vcpu, r, reg, uaddr);
> +
> + if (r->access == trap_debug32)
> + return debug_get32(vcpu, r, reg, uaddr);
> +
> return reg_to_user(uaddr, &vcpu_sys_reg(vcpu, r->reg), reg->id);
> }
>
> @@ -1321,6 +1395,12 @@ 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->access == trap_debug64)
> + return debug_set64(vcpu, r, reg, uaddr);
> +
> + if (r->access == trap_debug32)
> + return debug_set32(vcpu, r, reg, uaddr);
> +
> return reg_from_user(&vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
> }
>
> --
> 2.4.1
>
Thanks,
-Christoffer
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