From 721c624de88f364ae6a9acf9c31b1c576761f801 Mon Sep 17 00:00:00 2001
From: Wenkai Du <43822138+wenkaidu@users.noreply.github.com>
Date: Thu, 8 Jan 2026 13:55:40 -0800
Subject: [PATCH] Remove iommu warning in KVM env (#2112)

* Remove iommu warning in KVM env

* Fix for review comments

[ROCm/rccl commit: de931f4c53158184b2d7f4fe6165a5dad761649c]
---
 projects/rccl/src/init.cc | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/projects/rccl/src/init.cc b/projects/rccl/src/init.cc
index 28de2f70c7..1b8d6f6513 100644
--- a/projects/rccl/src/init.cc
+++ b/projects/rccl/src/init.cc
@@ -60,6 +60,7 @@
 #include "msccl/msccl_status.h"
 #include "latency_profiler/CollTrace.h"
 #include "latency_profiler/CollTraceFunc.h"
+#include  <cpuid.h>
 
 #ifndef STR2
   #define STR2(v) #v
@@ -198,8 +199,12 @@ static ncclResult_t ncclInit() {
     }
     INFO(NCCL_INIT, "Kernel version: %s", verStr);
     if (strstr(verStr, "cray") == NULL) {
+      unsigned int eax, ebx, ecx, edx;
+      if (!__get_cpuid(1, &eax, &ebx, &ecx, &edx))
+        ecx = 0; // cpuid not supported
       NCCLCHECK(ncclTopoGetStrFromSys("/sys/devices/virtual/dmi/id", "bios_version", strValue));
-      if (strncmp("Hyper-V UEFI Release", strValue, 20) != 0) {
+      // Check BIOS string and hypervisor presence on ecx bit 31
+      if (strncmp("Hyper-V UEFI Release", strValue, 20) != 0 && (ecx & (1u << 31)) == 0) {
         FILE* file;
         if ((file = fopen("/proc/cmdline", "r")) != NULL) {
           if (feof(file) == 0 && ferror(file) == 0) {