[Xen-devel] [PATCH v2 2/4] hvm/svm: Enable Breakpoint events

[Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>]

This commit enables the breakpoint events for svm.

Signed-off-by: Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>

---
Changes since V1:
        - Clean up bool_t
        - Removed event.insn_len = 0
        - Switched the v->domain->debugger_attached if
        - Add a extra pair of brachets for the capab var.
---
 xen/arch/x86/hvm/svm/svm.c    | 48 +++++++++++++++++++++++++++++++++++--------
 xen/include/asm-x86/monitor.h |  4 ++--
 2 files changed, 42 insertions(+), 10 deletions(-)

diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index dcbd550..a14caab 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -59,6 +59,7 @@
 #include <asm/hap.h>
 #include <asm/apic.h>
 #include <asm/debugger.h>
+#include <asm/hvm/monitor.h>
 #include <asm/xstate.h>
 
 void svm_asm_do_resume(void);
@@ -1079,7 +1080,8 @@ static void svm_ctxt_switch_to(struct vcpu *v)
 static void noreturn svm_do_resume(struct vcpu *v)
 {
     struct vmcb_struct *vmcb = v->arch.hvm_svm.vmcb;
-    bool_t debug_state = v->domain->debugger_attached;
+    bool debug_state = v->domain->debugger_attached
+                || v->domain->arch.monitor.software_breakpoint_enabled;
     bool_t vcpu_guestmode = 0;
     struct vlapic *vlapic = vcpu_vlapic(v);
 
@@ -2407,6 +2409,19 @@ 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,
@@ -2619,14 +2634,31 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
         break;
 
     case VMEXIT_EXCEPTION_BP:
-        if ( !v->domain->debugger_attached )
-            goto unexpected_exit_type;
-        /* AMD Vol2, 15.11: INT3, INTO, BOUND intercepts do not update RIP. */
-        if ( (inst_len = __get_instruction_length(v, INSTR_INT3)) == 0 )
+        inst_len = __get_instruction_length(v, INSTR_INT3);
+
+        if ( inst_len == 0 )
             break;
-        __update_guest_eip(regs, inst_len);
-        current->arch.gdbsx_vcpu_event = TRAP_int3;
-        domain_pause_for_debugger();
+
+        if ( v->domain->debugger_attached )
+        {
+            __update_guest_eip(regs, inst_len);
+            current->arch.gdbsx_vcpu_event = TRAP_int3;
+            domain_pause_for_debugger();
+        }
+        else
+        {
+        /* AMD Vol2, 15.11: INT3, INTO, BOUND intercepts do not update RIP. */
+           int rc;
+
+           rc = hvm_monitor_debug(regs->rip,
+                                  HVM_MONITOR_SOFTWARE_BREAKPOINT,
+                                  X86_EVENTTYPE_SW_EXCEPTION,
+                                  inst_len);
+           if ( rc < 0 )
+               goto unexpected_exit_type;
+           if ( !rc )
+               svm_propagate_intr(v, inst_len);
+        }
         break;
 
     case VMEXIT_EXCEPTION_NM:
diff --git a/xen/include/asm-x86/monitor.h b/xen/include/asm-x86/monitor.h
index b2b4e6a..68e62bd 100644
--- a/xen/include/asm-x86/monitor.h
+++ b/xen/include/asm-x86/monitor.h
@@ -81,7 +81,6 @@ static inline uint32_t arch_monitor_get_capabilities(struct 
domain *d)
     {
         capabilities = (1U << XEN_DOMCTL_MONITOR_EVENT_WRITE_CTRLREG) |
                        (1U << XEN_DOMCTL_MONITOR_EVENT_MOV_TO_MSR) |
-                       (1U << XEN_DOMCTL_MONITOR_EVENT_SOFTWARE_BREAKPOINT) |
                        (1U << XEN_DOMCTL_MONITOR_EVENT_DEBUG_EXCEPTION) |
                        (1U << XEN_DOMCTL_MONITOR_EVENT_CPUID) |
                        (1U << XEN_DOMCTL_MONITOR_EVENT_INTERRUPT) |
@@ -92,7 +91,8 @@ static inline uint32_t arch_monitor_get_capabilities(struct 
domain *d)
             capabilities |= (1U << XEN_DOMCTL_MONITOR_EVENT_SINGLESTEP);
     }
 
-    capabilities |= (1U << XEN_DOMCTL_MONITOR_EVENT_GUEST_REQUEST);
+    capabilities |= ((1U << XEN_DOMCTL_MONITOR_EVENT_GUEST_REQUEST) |
+                    (1U << XEN_DOMCTL_MONITOR_EVENT_SOFTWARE_BREAKPOINT));
 
     if ( hvm_funcs.set_descriptor_access_exiting )
         capabilities |= (1U << XEN_DOMCTL_MONITOR_EVENT_DESC_ACCESS);
-- 
2.7.4


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