Author: jhb
Date: Fri Aug 27 18:55:48 2010
New Revision: 211892
URL: http://svn.freebsd.org/changeset/base/211892

Log:
  MFC 210774,210935:
  - Tweak the logic to disable CLFLUSH in virtual environments to work around
    problems with flushing the local APIC register range so that it checks
    vm_guest directly.
  - Add Xen to the list of virtual vendors.  In the non PV (HVM) case this
    fixes the virtualization detection successfully disabling the CLFLUSH
    instruction.

Modified:
  stable/7/sys/amd64/amd64/initcpu.c
  stable/7/sys/i386/i386/initcpu.c
  stable/7/sys/kern/subr_param.c
Directory Properties:
  stable/7/sys/   (props changed)
  stable/7/sys/cddl/contrib/opensolaris/   (props changed)
  stable/7/sys/contrib/dev/acpica/   (props changed)
  stable/7/sys/contrib/pf/   (props changed)

Modified: stable/7/sys/amd64/amd64/initcpu.c
==============================================================================
--- stable/7/sys/amd64/amd64/initcpu.c  Fri Aug 27 18:55:24 2010        
(r211891)
+++ stable/7/sys/amd64/amd64/initcpu.c  Fri Aug 27 18:55:48 2010        
(r211892)
@@ -177,17 +177,17 @@ initializecpucache()
        if ((cpu_feature & CPUID_CLFSH) != 0)
                cpu_clflush_line_size = ((cpu_procinfo >> 8) & 0xff) * 8;
        /*
-        * XXXKIB: (temporary) hack to work around traps generated when
-        * CLFLUSHing APIC registers window.
+        * XXXKIB: (temporary) hack to work around traps generated
+        * when CLFLUSHing APIC register window under virtualization
+        * environments.  These environments tend to disable the
+        * CPUID_SS feature even though the native CPU supports it.
         */
        TUNABLE_INT_FETCH("hw.clflush_disable", &hw_clflush_disable);
-       if (cpu_vendor_id == CPU_VENDOR_INTEL && !(cpu_feature & CPUID_SS) &&
-           hw_clflush_disable == -1)
+       if (vm_guest != VM_GUEST_NO && hw_clflush_disable == -1)
                cpu_feature &= ~CPUID_CLFSH;
        /*
         * Allow to disable CLFLUSH feature manually by
-        * hw.clflush_disable tunable.  This may help Xen guest on some AMD
-        * CPUs.
+        * hw.clflush_disable tunable.
         */
        if (hw_clflush_disable == 1)
                cpu_feature &= ~CPUID_CLFSH;

Modified: stable/7/sys/i386/i386/initcpu.c
==============================================================================
--- stable/7/sys/i386/i386/initcpu.c    Fri Aug 27 18:55:24 2010        
(r211891)
+++ stable/7/sys/i386/i386/initcpu.c    Fri Aug 27 18:55:48 2010        
(r211892)
@@ -724,17 +724,17 @@ initializecpu(void)
        if ((cpu_feature & CPUID_CLFSH) != 0)
                cpu_clflush_line_size = ((cpu_procinfo >> 8) & 0xff) * 8;
        /*
-        * XXXKIB: (temporary) hack to work around traps generated when
-        * CLFLUSHing APIC registers window.
+        * XXXKIB: (temporary) hack to work around traps generated
+        * when CLFLUSHing APIC register window under virtualization
+        * environments.  These environments tend to disable the
+        * CPUID_SS feature even though the native CPU supports it.
         */
        TUNABLE_INT_FETCH("hw.clflush_disable", &hw_clflush_disable);
-       if (cpu_vendor_id == CPU_VENDOR_INTEL && !(cpu_feature & CPUID_SS) &&
-           hw_clflush_disable == -1)
+       if (vm_guest != VM_GUEST_NO && hw_clflush_disable == -1)
                cpu_feature &= ~CPUID_CLFSH;
        /*
         * Allow to disable CLFLUSH feature manually by
-        * hw.clflush_disable tunable.  This may help Xen guest on some AMD
-        * CPUs.
+        * hw.clflush_disable tunable.
         */
        if (hw_clflush_disable == 1)
                cpu_feature &= ~CPUID_CLFSH;

Modified: stable/7/sys/kern/subr_param.c
==============================================================================
--- stable/7/sys/kern/subr_param.c      Fri Aug 27 18:55:24 2010        
(r211891)
+++ stable/7/sys/kern/subr_param.c      Fri Aug 27 18:55:48 2010        
(r211892)
@@ -145,6 +145,7 @@ static const char *const vm_bnames[] = {
        "QEMU",                         /* QEMU */
        "Plex86",                       /* Plex86 */
        "Bochs",                        /* Bochs */
+       "Xen",                          /* Xen */
        NULL
 };
 
_______________________________________________
svn-src-all@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"

Reply via email to