svn commit: r211891 - in stable/8/sys: amd64/amd64 i386/i386 kern

John Baldwin jhb at FreeBSD.org
Fri Aug 27 18:55:24 UTC 2010


Author: jhb
Date: Fri Aug 27 18:55:24 2010
New Revision: 211891
URL: http://svn.freebsd.org/changeset/base/211891

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/8/sys/amd64/amd64/initcpu.c
  stable/8/sys/i386/i386/initcpu.c
  stable/8/sys/kern/subr_param.c
Directory Properties:
  stable/8/sys/   (props changed)
  stable/8/sys/amd64/include/xen/   (props changed)
  stable/8/sys/cddl/contrib/opensolaris/   (props changed)
  stable/8/sys/contrib/dev/acpica/   (props changed)
  stable/8/sys/contrib/pf/   (props changed)
  stable/8/sys/dev/xen/xenpci/   (props changed)

Modified: stable/8/sys/amd64/amd64/initcpu.c
==============================================================================
--- stable/8/sys/amd64/amd64/initcpu.c	Fri Aug 27 18:50:32 2010	(r211890)
+++ stable/8/sys/amd64/amd64/initcpu.c	Fri Aug 27 18:55:24 2010	(r211891)
@@ -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/8/sys/i386/i386/initcpu.c
==============================================================================
--- stable/8/sys/i386/i386/initcpu.c	Fri Aug 27 18:50:32 2010	(r211890)
+++ stable/8/sys/i386/i386/initcpu.c	Fri Aug 27 18:55:24 2010	(r211891)
@@ -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/8/sys/kern/subr_param.c
==============================================================================
--- stable/8/sys/kern/subr_param.c	Fri Aug 27 18:50:32 2010	(r211890)
+++ stable/8/sys/kern/subr_param.c	Fri Aug 27 18:55:24 2010	(r211891)
@@ -149,6 +149,7 @@ static const char *const vm_bnames[] = {
 	"QEMU",				/* QEMU */
 	"Plex86",			/* Plex86 */
 	"Bochs",			/* Bochs */
+	"Xen",				/* Xen */
 	NULL
 };
 


More information about the svn-src-all mailing list