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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v6] hvm/svm: Implement Debug events
On Mon, Mar 26, 2018 at 3:43 AM, Alexandru Isaila
<aisaila@xxxxxxxxxxxxxxx> wrote:
> At this moment the Debug events for the AMD architecture are not
> forwarded to the monitor layer.
>
> This patch adds the Debug event to the common capabilities, adds
> the VMEXIT_ICEBP then forwards the event to the monitor layer.
>
> Chapter 2: SVM Processor and Platform Extensions: "Note: A vector 1
> exception generated by the single byte INT1
> instruction (also known as ICEBP) does not trigger the #DB
> intercept. Software should use the dedicated ICEBP
> intercept to intercept ICEBP"
>
> Signed-off-by: Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>
Monitor bits:
Acked-by: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>
>
> ---
> Changes since V5:
> -Reformulate if in case VMEXIT_ICEBP
> ---
> xen/arch/x86/hvm/svm/emulate.c | 1 +
> xen/arch/x86/hvm/svm/svm.c | 65
> ++++++++++++++++++++++++++---------
> xen/arch/x86/monitor.c | 3 ++
> xen/include/asm-x86/hvm/hvm.h | 25 ++++++++++++++
> xen/include/asm-x86/hvm/svm/emulate.h | 1 +
> xen/include/asm-x86/monitor.h | 4 +--
> 6 files changed, 81 insertions(+), 18 deletions(-)
>
> diff --git a/xen/arch/x86/hvm/svm/emulate.c b/xen/arch/x86/hvm/svm/emulate.c
> index e1a1581..535674e 100644
> --- a/xen/arch/x86/hvm/svm/emulate.c
> +++ b/xen/arch/x86/hvm/svm/emulate.c
> @@ -65,6 +65,7 @@ static const struct {
> } opc_tab[INSTR_MAX_COUNT] = {
> [INSTR_PAUSE] = { X86EMUL_OPC_F3(0, 0x90) },
> [INSTR_INT3] = { X86EMUL_OPC( 0, 0xcc) },
> + [INSTR_ICEBP] = { X86EMUL_OPC( 0, 0xf1) },
> [INSTR_HLT] = { X86EMUL_OPC( 0, 0xf4) },
> [INSTR_XSETBV] = { X86EMUL_OPC(0x0f, 0x01), MODRM(3, 2, 1) },
> [INSTR_VMRUN] = { X86EMUL_OPC(0x0f, 0x01), MODRM(3, 3, 0) },
> diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
> index c34f5b5..1bdb8e0 100644
> --- a/xen/arch/x86/hvm/svm/svm.c
> +++ b/xen/arch/x86/hvm/svm/svm.c
> @@ -172,6 +172,24 @@ static void svm_enable_msr_interception(struct domain
> *d, uint32_t msr)
> svm_intercept_msr(v, msr, MSR_INTERCEPT_WRITE);
> }
>
> +static void svm_set_icebp_interception(struct domain *d, bool enable)
> +{
> + const struct vcpu *v;
> +
> + for_each_vcpu ( d, v )
> + {
> + struct vmcb_struct *vmcb = v->arch.hvm_svm.vmcb;
> + uint32_t intercepts = vmcb_get_general2_intercepts(vmcb);
> +
> + if ( enable )
> + intercepts |= GENERAL2_INTERCEPT_ICEBP;
> + else
> + intercepts &= ~GENERAL2_INTERCEPT_ICEBP;
> +
> + vmcb_set_general2_intercepts(vmcb, intercepts);
> + }
> +}
> +
> static void svm_save_dr(struct vcpu *v)
> {
> struct vmcb_struct *vmcb = v->arch.hvm_svm.vmcb;
> @@ -1109,7 +1127,8 @@ static void noreturn svm_do_resume(struct vcpu *v)
> {
> struct vmcb_struct *vmcb = v->arch.hvm_svm.vmcb;
> bool debug_state = (v->domain->debugger_attached ||
> - v->domain->arch.monitor.software_breakpoint_enabled);
> + v->domain->arch.monitor.software_breakpoint_enabled
> ||
> + v->domain->arch.monitor.debug_exception_enabled);
> bool_t vcpu_guestmode = 0;
> struct vlapic *vlapic = vcpu_vlapic(v);
>
> @@ -2438,19 +2457,6 @@ static bool svm_get_pending_event(struct vcpu *v,
> struct x86_event *info)
> return true;
> }
>
> -static void svm_propagate_intr(struct vcpu *v, unsigned long insn_len)
> -{
> - struct vmcb_struct *vmcb = v->arch.hvm_svm.vmcb;
> - struct x86_event event = {
> - .vector = vmcb->eventinj.fields.type,
> - .type = vmcb->eventinj.fields.type,
> - .error_code = vmcb->exitinfo1,
> - };
> -
> - event.insn_len = insn_len;
> - hvm_inject_event(&event);
> -}
> -
> static struct hvm_function_table __initdata svm_function_table = {
> .name = "SVM",
> .cpu_up_prepare = svm_cpu_up_prepare,
> @@ -2490,6 +2496,7 @@ static struct hvm_function_table __initdata
> svm_function_table = {
> .msr_read_intercept = svm_msr_read_intercept,
> .msr_write_intercept = svm_msr_write_intercept,
> .enable_msr_interception = svm_enable_msr_interception,
> + .set_icebp_interception = svm_set_icebp_interception,
> .set_rdtsc_exiting = svm_set_rdtsc_exiting,
> .set_descriptor_access_exiting = svm_set_descriptor_access_exiting,
> .get_insn_bytes = svm_get_insn_bytes,
> @@ -2656,9 +2663,33 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
> HVMTRACE_0D(SMI);
> break;
>
> + case VMEXIT_ICEBP:
> case VMEXIT_EXCEPTION_DB:
> if ( !v->domain->debugger_attached )
> - hvm_inject_hw_exception(TRAP_debug, X86_EVENT_NO_EC);
> + {
> + int rc;
> + unsigned int trap_type;
> +
> + if ( likely(exit_reason != VMEXIT_ICEBP) )
> + {
> + trap_type = X86_EVENTTYPE_HW_EXCEPTION;
> + inst_len = 0;
> + }
> + else
> + {
> + trap_type = X86_EVENTTYPE_PRI_SW_EXCEPTION;
> + inst_len = __get_instruction_length(v, INSTR_ICEBP);
> + }
> +
> + rc = hvm_monitor_debug(regs->rip,
> + HVM_MONITOR_DEBUG_EXCEPTION,
> + trap_type, inst_len);
> + if ( rc < 0 )
> + goto unexpected_exit_type;
> + if ( !rc )
> + hvm_inject_exception(TRAP_debug,
> + trap_type, inst_len, X86_EVENT_NO_EC);
> + }
> else
> domain_pause_for_debugger();
> break;
> @@ -2687,7 +2718,9 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
> if ( rc < 0 )
> goto unexpected_exit_type;
> if ( !rc )
> - svm_propagate_intr(v, inst_len);
> + hvm_inject_exception(TRAP_int3,
> + X86_EVENTTYPE_SW_EXCEPTION,
> + inst_len, X86_EVENT_NO_EC);
> }
> break;
>
> diff --git a/xen/arch/x86/monitor.c b/xen/arch/x86/monitor.c
> index 4317658..3fb6531 100644
> --- a/xen/arch/x86/monitor.c
> +++ b/xen/arch/x86/monitor.c
> @@ -288,6 +288,9 @@ int arch_monitor_domctl_event(struct domain *d,
> ad->monitor.debug_exception_sync = requested_status ?
> mop->u.debug_exception.sync :
> 0;
> +
> + hvm_set_icebp_interception(d, requested_status);
> +
> domain_unpause(d);
> break;
> }
> diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
> index 2376ed6..0775d0c 100644
> --- a/xen/include/asm-x86/hvm/hvm.h
> +++ b/xen/include/asm-x86/hvm/hvm.h
> @@ -209,6 +209,7 @@ struct hvm_function_table {
> bool_t access_w, bool_t access_x);
>
> void (*enable_msr_interception)(struct domain *d, uint32_t msr);
> + void (*set_icebp_interception)(struct domain *d, bool enable);
> bool_t (*is_singlestep_supported)(void);
>
> /* Alternate p2m */
> @@ -407,6 +408,20 @@ void hvm_migrate_pirqs(struct vcpu *v);
>
> void hvm_inject_event(const struct x86_event *event);
>
> +static inline void hvm_inject_exception(
> + unsigned int vector, unsigned int type,
> + unsigned int insn_len, int error_code)
> +{
> + struct x86_event event = {
> + .vector = vector,
> + .type = type,
> + .insn_len = insn_len,
> + .error_code = error_code,
> + };
> +
> + hvm_inject_event(&event);
> +}
> +
> static inline void hvm_inject_hw_exception(unsigned int vector, int errcode)
> {
> struct x86_event event = {
> @@ -581,6 +596,16 @@ static inline bool_t hvm_enable_msr_interception(struct
> domain *d, uint32_t msr)
> return 0;
> }
>
> +static inline bool hvm_set_icebp_interception(struct domain *d, bool enable)
> +{
> + if ( hvm_funcs.set_icebp_interception )
> + {
> + hvm_funcs.set_icebp_interception(d, enable);
> + return true;
> + }
> + return false;
> +}
> +
> static inline bool_t hvm_is_singlestep_supported(void)
> {
> return (hvm_funcs.is_singlestep_supported &&
> diff --git a/xen/include/asm-x86/hvm/svm/emulate.h
> b/xen/include/asm-x86/hvm/svm/emulate.h
> index 7c1dcd1..3de8236 100644
> --- a/xen/include/asm-x86/hvm/svm/emulate.h
> +++ b/xen/include/asm-x86/hvm/svm/emulate.h
> @@ -38,6 +38,7 @@ enum instruction_index {
> INSTR_STGI,
> INSTR_CLGI,
> INSTR_INVLPGA,
> + INSTR_ICEBP,
> INSTR_MAX_COUNT /* Must be last - Number of instructions supported */
> };
>
> diff --git a/xen/include/asm-x86/monitor.h b/xen/include/asm-x86/monitor.h
> index 99ed4b87..c5a86d1 100644
> --- a/xen/include/asm-x86/monitor.h
> +++ b/xen/include/asm-x86/monitor.h
> @@ -82,12 +82,12 @@ static inline uint32_t
> arch_monitor_get_capabilities(struct domain *d)
> (1U << XEN_DOMCTL_MONITOR_EVENT_MOV_TO_MSR) |
> (1U << XEN_DOMCTL_MONITOR_EVENT_INTERRUPT) |
> (1U << XEN_DOMCTL_MONITOR_EVENT_CPUID) |
> + (1U << XEN_DOMCTL_MONITOR_EVENT_DEBUG_EXCEPTION) |
> (1U << XEN_DOMCTL_MONITOR_EVENT_WRITE_CTRLREG));
>
> if ( cpu_has_vmx )
> {
> - capabilities |= ((1U << XEN_DOMCTL_MONITOR_EVENT_DEBUG_EXCEPTION) |
> - (1U <<
> XEN_DOMCTL_MONITOR_EVENT_EMUL_UNIMPLEMENTED));
> + capabilities |= (1U << XEN_DOMCTL_MONITOR_EVENT_EMUL_UNIMPLEMENTED);
>
> /* Since we know this is on VMX, we can just call the hvm func */
> if ( hvm_is_singlestep_supported() )
> --
> 2.7.4
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