[xen staging] x86/APIC: drop 32-bit days remnants

[patchbot@xxxxxxx]

commit 8593782ace71149339adace3201d3467ae7bf502
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon Jan 24 08:40:13 2022 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Jan 24 08:40:13 2022 +0100

    x86/APIC: drop 32-bit days remnants
    
    Mercury and Neptune were Pentium chipsets - no need to work around their
    errata, even more so that the workaround looks fragile.
    
    Also ditch a Pentium-related and stale part of a comment.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/apic.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/xen/arch/x86/apic.c b/xen/arch/x86/apic.c
index 5d3e1f3952..5836561585 100644
--- a/xen/arch/x86/apic.c
+++ b/xen/arch/x86/apic.c
@@ -1042,11 +1042,6 @@ static void __init wait_8254_wraparound(void)
     do {
         prev_count = curr_count;
         curr_count = get_8254_timer_count();
-
-        /* workaround for broken Mercury/Neptune */
-        if (prev_count >= curr_count + 0x100)
-            curr_count = get_8254_timer_count();
-        
     } while (prev_count >= curr_count);
 }
 
@@ -1056,9 +1051,6 @@ static void __init wait_8254_wraparound(void)
  * this function twice on the boot CPU, once with a bogus timeout
  * value, second time for real. The other (noncalibrating) CPUs
  * call this function only once, with the real, calibrated value.
- *
- * We do reads before writes even if unnecessary, to get around the
- * P5 APIC double write bug.
  */
 
 #define APIC_DIVISOR 1
--
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