From: Jan Beulich
The emulation_count field is set only conditionally right now. Convert
all field setting to an initializer, thus guaranteeing that field to be
set to 0 (default initialized) when GUEST_PAGING_LEVELS != 3.
Rework trace_shadow_emulate() to be consistent with the other trace helpers.
Coverity-ID: 1598430
Fixes: 9a86ac1aa3d2 ("xentrace 5/7: Additional tracing for the shadow code")
Signed-off-by: Jan Beulich
Acked-by: Roger Pau Monné
---
CC: Jan Beulich
CC: Roger Pau Monné
CC: George Dunlap
v2:
* Rebase over packing/sh_trace() cleanup.
---
xen/arch/x86/mm/shadow/multi.c | 31 +++
1 file changed, 15 insertions(+), 16 deletions(-)
diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
index d2fe4e148fe0..47dd1cc626b2 100644
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -2063,30 +2063,29 @@ static void cf_check trace_emulate_write_val(
#endif
}
-static inline void trace_shadow_emulate(guest_l1e_t gl1e, unsigned long va)
+static inline void sh_trace_emulate(guest_l1e_t gl1e, unsigned long va)
{
if ( tb_init_done )
{
-struct __packed {
-/* for PAE, guest_l1e may be 64 while guest_va may be 32;
- so put it first for alignment sake. */
+struct {
+/*
+ * For GUEST_PAGING_LEVELS=3 (PAE paging), guest_l1e is 64 while
+ * guest_va is 32. Put it first to avoid padding.
+ */
guest_l1e_t gl1e, write_val;
guest_va_t va;
uint32_t flags:29, emulation_count:3;
-} d;
-u32 event;
-
-event = TRC_SHADOW_EMULATE | ((GUEST_PAGING_LEVELS-2)<<8);
-
-d.gl1e = gl1e;
-d.write_val.l1 = this_cpu(trace_emulate_write_val);
-d.va = va;
+} d = {
+.gl1e = gl1e,
+.write_val.l1 = this_cpu(trace_emulate_write_val),
+.va = va,
#if GUEST_PAGING_LEVELS == 3
-d.emulation_count = this_cpu(trace_extra_emulation_count);
+.emulation_count = this_cpu(trace_extra_emulation_count),
#endif
-d.flags = this_cpu(trace_shadow_path_flags);
+.flags = this_cpu(trace_shadow_path_flags),
+};
-trace(event, sizeof(d), &d);
+sh_trace(TRC_SHADOW_EMULATE, sizeof(d), &d);
}
}
#endif /* CONFIG_HVM */
@@ -2815,7 +2814,7 @@ static int cf_check sh_page_fault(
}
#endif /* PAE guest */
-trace_shadow_emulate(gw.l1e, va);
+sh_trace_emulate(gw.l1e, va);
emulate_done:
SHADOW_PRINTK("emulated\n");
return EXCRET_fault_fixed;
--
2.30.2
