Re: [Qemu-devel] [PATCH v6 08/18] intel_iommu: fix trace for addr translation

[Peter Xu <peterx@redhat.com>]

On Tue, Feb 07, 2017 at 01:40:39PM +0800, Jason Wang wrote:
> 
> 
> On 2017年02月03日 16:22, Peter Xu wrote:
> >Another patch to convert the DPRINTF() stuffs. This patch focuses on the
> >address translation path and caching.
> >
> >Signed-off-by: Peter Xu<peterx@redhat.com>
> >---
> >  hw/i386/intel_iommu.c | 84 ++++++++++++++++++++-------------------------------
> >  hw/i386/trace-events  |  7 +++++
> >  2 files changed, 39 insertions(+), 52 deletions(-)
> 
> Similar to previous patch, this in fact a conversion not a fix.

I'll fix the subject.

> 
> >
> >diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> >index d7b9a01..c672621 100644
> >--- a/hw/i386/intel_iommu.c
> >+++ b/hw/i386/intel_iommu.c
> >@@ -260,11 +260,9 @@ static void vtd_update_iotlb(IntelIOMMUState *s, uint16_t source_id,
> >      uint64_t *key = g_malloc(sizeof(*key));
> >      uint64_t gfn = vtd_get_iotlb_gfn(addr, level);
> >-    VTD_DPRINTF(CACHE, "update iotlb sid 0x%"PRIx16 " iova 0x%"PRIx64
> >-                " slpte 0x%"PRIx64 " did 0x%"PRIx16, source_id, addr, slpte,
> >-                domain_id);
> >+    trace_vtd_iotlb_page_update(source_id, addr, slpte, domain_id);
> >      if (g_hash_table_size(s->iotlb) >= VTD_IOTLB_MAX_SIZE) {
> >-        VTD_DPRINTF(CACHE, "iotlb exceeds size limit, forced to reset");
> >+        trace_vtd_iotlb_reset("iotlb exceeds size limit");
> >          vtd_reset_iotlb(s);
> >      }
> >@@ -505,8 +503,7 @@ static int vtd_get_root_entry(IntelIOMMUState *s, uint8_t index,
> >      addr = s->root + index * sizeof(*re);
> >      if (dma_memory_read(&address_space_memory, addr, re, sizeof(*re))) {
> >-        VTD_DPRINTF(GENERAL, "error: fail to access root-entry at 0x%"PRIx64
> >-                    " + %"PRIu8, s->root, index);
> >+        trace_vtd_err("Fail to access root-entry");
> 
> Looks like some information were removed which may be valuable for
> debugging, any reason for do this?

I was trying to avoid introducing unnecessary traces, and I did a
judgement on which one is important.

I'll keep all the fields printed and add new traces for each of them
if you really want it.

Thanks,

-- peterx