https://github.com/VirtualBox/virtualbox/commit/8902311a0d88a2d14a1b8ee224008a4c7061854b

From 8902311a0d88a2d14a1b8ee224008a4c7061854b Mon Sep 17 00:00:00 2001
From: Vadim Galitsyn <vadim.galitsyn@oracle.com>
Date: Tue, 17 Feb 2026 15:20:09 +0000
Subject: [PATCH] Linux host: Introduce initial support for kernel 6.19 (build
 fix), bugref:11038.

svn:sync-xref-src-repo-rev: r172810
--- a/vboxdrv/linux/SUPDrv-linux.c
+++ b/vboxdrv/linux/SUPDrv-linux.c
@@ -1199,18 +1199,19 @@ SUPR0DECL(int) SUPDrvLinuxLdrDeregisterWrappedModule(PCSUPLDRWRAPPEDMODULE pWrap
 }
 EXPORT_SYMBOL(SUPDrvLinuxLdrDeregisterWrappedModule);
 
+#if RTLNX_VER_MIN(5,8,0)
 /**
  * Wrapper function for cr4_update_irqsoff() which was
  * exported only for KVM starting from kernel 6.19.
  */
 static void supdrvLinux_cr4_update_irqsoff(unsigned long set, unsigned long clear)
 {
-#if RTLNX_VER_MIN(6,19,0) && defined(SUPDRV_LINUX_HAS_KVM_HWVIRT_API)
+# if RTLNX_VER_MIN(6,19,0) && defined(SUPDRV_LINUX_HAS_KVM_HWVIRT_API)
     if (g_pfnCr4UpdateIrqsoff)
         g_pfnCr4UpdateIrqsoff(set, clear);
-#else
+# else
     cr4_update_irqsoff(set, clear);
-#endif
+# endif
 }
 
 /**
@@ -1220,14 +1221,15 @@ static void supdrvLinux_cr4_update_irqsoff(unsigned long set, unsigned long clea
 static unsigned long supdrvLinux_cr4_read_shadow(void)
 {
     unsigned long cr4 = 0;
-#if RTLNX_VER_MIN(6,19,0) && defined(SUPDRV_LINUX_HAS_KVM_HWVIRT_API)
+# if RTLNX_VER_MIN(6,19,0) && defined(SUPDRV_LINUX_HAS_KVM_HWVIRT_API)
     if (g_pfnCr4ReadShadow)
         cr4 = g_pfnCr4ReadShadow();
-#else
+# else
     cr4 = cr4_read_shadow();
-#endif
+# endif
     return cr4;
 }
+#endif /* 5.8.0 */
 
 #if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
 RTCCUINTREG VBOXCALL supdrvOSChangeCR4(RTCCUINTREG fOrMask, RTCCUINTREG fAndMask)