File xen.xentrace-74584a367051bc0d6f4b96fd360fa7bc6538fc39.patch of Package xen

From: Olaf Hering <olaf@aepfle.de>
Date: Mon, 19 Jun 2023 12:18:13 +0200
Subject: xentrace 74584a367051bc0d6f4b96fd360fa7bc6538fc39

Revert "xentrace: handle sparse cpu ids correctly in xen trace buffer handling"

This reverts commit 74584a367051bc0d6f4b96fd360fa7bc6538fc39.
---
 tools/xentrace/xentrace.c | 2 +-
 xen/common/trace.c        | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

--- a/tools/xentrace/xentrace.c
+++ b/tools/xentrace/xentrace.c
@@ -591,25 +591,25 @@ static unsigned int get_num_cpus(void)
 {
     xc_physinfo_t physinfo;
     int ret;
     
     ret = xc_physinfo(xc_handle, &physinfo);
     
     if ( ret != 0 )
     {
         PERROR("Failure to get logical CPU count from Xen");
         exit(EXIT_FAILURE);
     }
 
-    return physinfo.max_cpu_id + 1;
+    return physinfo.nr_cpus;
 }
 
 /**
  * event_init - setup to receive the VIRQ_TBUF event
  */
 static void event_init(void)
 {
     int rc;
 
     xce_handle = xenevtchn_open(NULL, 0);
     if (xce_handle == NULL) {
         perror("event channel open");
--- a/xen/common/trace.c
+++ b/xen/common/trace.c
@@ -101,25 +101,25 @@ static uint32_t calc_tinfo_first_offset(void)
  * in the currently sized struct t_info and allows prod and cons to
  * reach double the value without overflow.
  * The t_info layout is fixed and cant be changed without breaking xentrace.
  * Initialize t_info_pages based on number of trace pages.
  */
 static int calculate_tbuf_size(unsigned int pages, uint16_t t_info_first_offset)
 {
     struct t_buf dummy_size;
     typeof(dummy_size.prod) max_size;
     struct t_info dummy_pages;
     typeof(dummy_pages.tbuf_size) max_pages;
     typeof(dummy_pages.mfn_offset[0]) max_mfn_offset;
-    unsigned int max_cpus = nr_cpu_ids;
+    unsigned int max_cpus = num_online_cpus();
     unsigned int t_info_words;
 
     /* force maximum value for an unsigned type */
     max_size = -1;
     max_pages = -1;
     max_mfn_offset = -1;
 
     /* max size holds up to n pages */
     max_size /= PAGE_SIZE;
 
     if ( max_size < max_pages )
         max_pages = max_size;
@@ -137,31 +137,31 @@ static int calculate_tbuf_size(unsigned int pages, uint16_t t_info_first_offset)
         max_pages = max_mfn_offset;
 
     if ( pages > max_pages )
     {
         printk(XENLOG_INFO "xentrace: requested number of %u pages "
                "reduced to %u\n",
                pages, max_pages);
         pages = max_pages;
     }
 
     /*
      * NB this calculation is correct, because t_info_first_offset is
-     * in words, not bytes
+     * in words, not bytes, not bytes
      */
-    t_info_words = nr_cpu_ids * pages + t_info_first_offset;
+    t_info_words = num_online_cpus() * pages + t_info_first_offset;
     t_info_pages = PFN_UP(t_info_words * sizeof(uint32_t));
     printk(XENLOG_INFO "xentrace: requesting %u t_info pages "
            "for %u trace pages on %u cpus\n",
-           t_info_pages, pages, nr_cpu_ids);
+           t_info_pages, pages, num_online_cpus());
     return pages;
 }
 
 /**
  * alloc_trace_bufs - performs initialization of the per-cpu trace buffers.
  *
  * This function is called at start of day in order to initialize the per-cpu
  * trace buffers.  The trace buffers are then available for debugging use, via
  * the %TRACE_xD macros exported in <xen/trace.h>.
  *
  * This function may also be called later when enabling trace buffers
  * via the SET_SIZE hypercall.