[PATCH 05/16] util/vfio-helpers: Trace PCI I/O config accesses

[Philippe Mathieu-Daudé]

We sometime get kernel panic with some devices on Aarch64
hosts. Alex Williamson suggests it might be broken PCIe
root complex. Add trace event to record the latest I/O
access before crashing. In case, assert our accesses are
aligned.

Reviewed-by: Fam Zheng <fam@euphon.net>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 util/vfio-helpers.c | 8 ++++++++
 util/trace-events   | 2 ++
 2 files changed, 10 insertions(+)

diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c
index bce2cdb2f3c..ac9cc20ce29 100644
--- a/util/vfio-helpers.c
+++ b/util/vfio-helpers.c
@@ -228,6 +228,10 @@ static int qemu_vfio_pci_read_config(QEMUVFIOState *s, 
void *buf,
 {
     int ret;
 
+    trace_qemu_vfio_pci_read_config(buf, ofs, size,
+                                    s->config_region_info.offset,
+                                    s->config_region_info.size);
+    assert(QEMU_IS_ALIGNED(s->config_region_info.offset + ofs, size));
     do {
         ret = pread(s->device, buf, size, s->config_region_info.offset + ofs);
     } while (ret == -1 && errno == EINTR);
@@ -238,6 +242,10 @@ static int qemu_vfio_pci_write_config(QEMUVFIOState *s, 
void *buf, int size, int
 {
     int ret;
 
+    trace_qemu_vfio_pci_write_config(buf, ofs, size,
+                                     s->config_region_info.offset,
+                                     s->config_region_info.size);
+    assert(QEMU_IS_ALIGNED(s->config_region_info.offset + ofs, size));
     do {
         ret = pwrite(s->device, buf, size, s->config_region_info.offset + ofs);
     } while (ret == -1 && errno == EINTR);
diff --git a/util/trace-events b/util/trace-events
index 19f03f14a33..b697d2d5429 100644
--- a/util/trace-events
+++ b/util/trace-events
@@ -86,3 +86,5 @@ qemu_vfio_do_mapping(void *s, void *host, size_t size, 
uint64_t iova) "s %p host
 qemu_vfio_dma_map(void *s, void *host, size_t size, bool temporary, uint64_t 
*iova) "s %p host %p size 0x%zx temporary %d iova %p"
 qemu_vfio_dma_unmap(void *s, void *host) "s %p host %p"
 qemu_vfio_iommu_iova_pgsizes(uint64_t iova_pgsizes) "iommu page size bitmask: 
0x%08"PRIx64
+qemu_vfio_pci_read_config(void *buf, int ofs, int size, uint64_t region_ofs, 
uint64_t region_size) "read cfg ptr %p ofs 0x%x size %d (region ofs 0x%"PRIx64" 
size %"PRId64")"
+qemu_vfio_pci_write_config(void *buf, int ofs, int size, uint64_t region_ofs, 
uint64_t region_size) "write cfg ptr %p ofs 0x%x size %d (region ofs 
0x%"PRIx64" size %"PRId64")"
-- 
2.26.2