From: Jan Beulich <jbeulich@suse.com>
Date: Thu, 12 Nov 2015 16:03:20 +0000 (+0100)
Subject: x86/event: correct debug event generation
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~2276
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=5ab6654cf0f2a90b23d5ab714fa49ae038d21e17;p=xen.git

x86/event: correct debug event generation

RIP is not a linear address, and hence should not on its own be subject
to GVA -> GFN translation. Once at it, move all of the (perhaps
expensive) operations in the two functions into their main if()'s body,
and improve the error code passed to the translation function.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Razvan Cojocaru <rcojocaru@bitdefender.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---

diff --git a/xen/arch/x86/hvm/event.c b/xen/arch/x86/hvm/event.c
index 4097af02ae..73c8f1430b 100644
--- a/xen/arch/x86/hvm/event.c
+++ b/xen/arch/x86/hvm/event.c
@@ -144,36 +144,59 @@ void hvm_event_guest_request(void)
     }
 }
 
-int hvm_event_int3(unsigned long gla)
+int hvm_event_int3(unsigned long rip)
 {
     int rc = 0;
-    uint32_t pfec = PFEC_page_present;
     struct vcpu *curr = current;
-    vm_event_request_t req = {
-        .reason = VM_EVENT_REASON_SOFTWARE_BREAKPOINT,
-        .vcpu_id = curr->vcpu_id,
-        .u.software_breakpoint.gfn = paging_gva_to_gfn(curr, gla, &pfec)
-    };
 
     if ( curr->domain->arch.monitor.software_breakpoint_enabled )
+    {
+        struct segment_register sreg;
+        uint32_t pfec = PFEC_page_present | PFEC_insn_fetch;
+        vm_event_request_t req = {
+            .reason = VM_EVENT_REASON_SOFTWARE_BREAKPOINT,
+            .vcpu_id = curr->vcpu_id,
+        };
+
+        hvm_get_segment_register(curr, x86_seg_ss, &sreg);
+        if ( sreg.attr.fields.dpl == 3 )
+            pfec |= PFEC_user_mode;
+
+        hvm_get_segment_register(curr, x86_seg_cs, &sreg);
+        req.u.software_breakpoint.gfn = paging_gva_to_gfn(curr,
+                                                          sreg.base + rip,
+                                                          &pfec);
+
         rc = hvm_event_traps(1, &req);
+    }
 
     return rc;
 }
 
-int hvm_event_single_step(unsigned long gla)
+int hvm_event_single_step(unsigned long rip)
 {
     int rc = 0;
-    uint32_t pfec = PFEC_page_present;
     struct vcpu *curr = current;
-    vm_event_request_t req = {
-        .reason = VM_EVENT_REASON_SINGLESTEP,
-        .vcpu_id = curr->vcpu_id,
-        .u.singlestep.gfn = paging_gva_to_gfn(curr, gla, &pfec)
-    };
 
     if ( curr->domain->arch.monitor.singlestep_enabled )
+    {
+        struct segment_register sreg;
+        uint32_t pfec = PFEC_page_present | PFEC_insn_fetch;
+        vm_event_request_t req = {
+            .reason = VM_EVENT_REASON_SINGLESTEP,
+            .vcpu_id = curr->vcpu_id,
+        };
+
+        hvm_get_segment_register(curr, x86_seg_ss, &sreg);
+        if ( sreg.attr.fields.dpl == 3 )
+            pfec |= PFEC_user_mode;
+
+        hvm_get_segment_register(curr, x86_seg_cs, &sreg);
+        req.u.singlestep.gfn = paging_gva_to_gfn(curr, sreg.base + rip,
+                                                 &pfec);
+
         rc = hvm_event_traps(1, &req);
+    }
 
     return rc;
 }
diff --git a/xen/include/asm-x86/hvm/event.h b/xen/include/asm-x86/hvm/event.h
index e07f3291f1..11eb1feb28 100644
--- a/xen/include/asm-x86/hvm/event.h
+++ b/xen/include/asm-x86/hvm/event.h
@@ -28,8 +28,8 @@ bool_t hvm_event_cr(unsigned int index, unsigned long value,
     hvm_event_cr(VM_EVENT_X86_##what, new, old)
 void hvm_event_msr(unsigned int msr, uint64_t value);
 /* Called for current VCPU: returns -1 if no listener */
-int hvm_event_int3(unsigned long gla);
-int hvm_event_single_step(unsigned long gla);
+int hvm_event_int3(unsigned long rip);
+int hvm_event_single_step(unsigned long rip);
 void hvm_event_guest_request(void);
 
 #endif /* __ASM_X86_HVM_EVENT_H__ */