On Fri, 2011-12-16 at 11:32 -0800, Alan Cox wrote:
Is anyone here actively working on fixing problems with SMP support
under PV i386? While doing some other maintenance on the
vm_page_alloc() callers in the source tree, I happened to take a look at
cpu_initialize_context() in mp_machdep.c. This function is involved in
bringing up the 2nd, 3rd, etc. CPUs on an SMP system. I spotted a
couple obvious errors. First, the size parameter given to kmem_*()
functions is expected to be in terms of bytes and not pages. Second, I
believe that PV i386 requires PAE to be used. If so, there are out of
range accesses to the array m[].
Index: i386/xen/mp_machdep.c
===
--- i386/xen/mp_machdep.c (revision 228561)
+++ i386/xen/mp_machdep.c (working copy)
@@ -810,7 +810,7 @@ cpu_initialize_context(unsigned int cpu)
{
/* vcpu_guest_context_t is too large to allocate on the stack.
* Hence we allocate statically and protect it with a lock */
- vm_page_t m[4];
+ vm_page_t m[NPGPTD + 2];
static vcpu_guest_context_t ctxt;
vm_offset_t boot_stack;
vm_offset_t newPTD;
@@ -831,8 +831,8 @@ cpu_initialize_context(unsigned int cpu)
pmap_zero_page(m[i]);
}
- boot_stack = kmem_alloc_nofault(kernel_map, 1);
- newPTD = kmem_alloc_nofault(kernel_map, NPGPTD);
+ boot_stack = kmem_alloc_nofault(kernel_map, PAGE_SIZE);
+ newPTD = kmem_alloc_nofault(kernel_map, NPGPTD * PAGE_SIZE);
ma[0] = VM_PAGE_TO_MACH(m[0])|PG_V;
#ifdef PAE
@@ -854,7 +854,7 @@ cpu_initialize_context(unsigned int cpu)
nkpt*sizeof(vm_paddr_t));
pmap_qremove(newPTD, 4);
- kmem_free(kernel_map, newPTD, 4);
+ kmem_free(kernel_map, newPTD, 4 * PAGE_SIZE);
/*
* map actual idle stack to boot_stack
*/
This seems happy on our ref9 VMs. I don't suppose this means I can go
above 768M of Ram now?
[root@xen1 sbruno]# /usr/sbin/xm create -c ref9-xen32
Using config file /etc/xen/ref9-xen32.
Started domain ref9-xen32 (id=106)
WARNING: loader(8) metadata is missing!
GDB: no debug ports present
KDB: debugger backends: ddb
KDB: current backend: ddb
Copyright (c) 1992-2011 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
The Regents of the University of California. All rights
reserved.
FreeBSD is a registered trademark of The FreeBSD Foundation.
FreeBSD 9.0-PRERELEASE #0: Sat Dec 17 16:13:02 PST 2011
sbr...@ref9-xen32.freebsd.org:/dumpster/scratch/sbruno-scratch/9/sys/i386/compile/XEN
i386
WARNING: WITNESS option enabled, expect reduced performance.
Xen reported: 2493.756 MHz processor.
Timecounter ixen frequency 1953125 Hz quality 0
CPU: Intel(R) Xeon(R) CPU L5420 @ 2.50GHz (2493.76-MHz
686-class CPU)
Origin = GenuineIntel Id = 0x10676 Family = 6 Model = 17
Stepping = 6
Features=0xbfe3fbffFPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE
Features2=0xce3bdSSE3,DTES64,MON,DS_CPL,VMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,DCA,SSE4.1
AMD Features=0x2010NX,LM
AMD Features2=0x1LAHF
real memory = 805306368 (768 MB)
avail memory = 776830976 (740 MB)
[XEN] IPI cpu=0 irq=128 vector=RESCHEDULE_VECTOR (0)
[XEN] IPI cpu=0 irq=129 vector=CALL_FUNCTION_VECTOR (1)
[XEN] xen_rtc_probe: probing Hypervisor RTC clock
rtc0: Xen Hypervisor Clock on motherboard
[XEN] xen_rtc_attach: attaching Hypervisor RTC clock
xenstore0: XenStore on motherboard
xc0: Xen Console on motherboard
Event timer ixen quality 600
Timecounters tick every 10.000 msec
xenbusb_front0: Xen Frontend Devices on xenstore0
[XEN] hypervisor wallclock nudged; nudging TOD.
xn0: Virtual Network Interface at device/vif/0 on xenbusb_front0
xn0: Ethernet address: 00:16:3e:00:00:03
xenbusb_back0: Xen Backend Devices on xenstore0
xctrl0: Xen Control Device on xenstore0
xn0: backend features: feature-sg feature-gso-tcp4
xbd0: 10240MB Virtual Block Device at device/vbd/768 on xenbusb_front0
xbd0: attaching as ad0
Timecounter TSC frequency 2493756000 Hz quality 800
WARNING: WITNESS option enabled, expect reduced performance.
Trying to mount root from ufs:/dev/ad0p2 []...
rtc0: [XEN] xen_rtc_gettime
rtc0: [XEN] xen_rtc_gettime: wallclock 1313550543 sec; 871707442 nsec
rtc0: [XEN] xen_rtc_gettime: uptime 10619933 sec; 620343100 nsec
rtc0: [XEN] xen_rtc_gettime: TOD 1324170477 sec; 492050542 nsec
Setting hostuuid: 1c127834-ab5a-c2e4-7b24-5ea29d364d9d.
Setting hostid: 0xdea9fbfd.
Entropy harvesting: interrupts ethernet point_to_point kickstart.
Starting file system checks:
/dev/ad0p2: FILE SYSTEM CLEAN; SKIPPING CHECKS
/dev/ad0p2: clean, 1874771 free (883 frags, 234236 blocks, 0.0%
fragmentation)
Mounting local file systems:.
Setting hostname: ref9-xen32.freebsd.org.
xn0: link state changed to DOWN
xn0: link state
