Re: [Xen-devel] [PATCH v15 00/23] Enable L2 Cache Allocation Technology & Refactor psr.c

[Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>]

On 17-08-03 18:50:02, Boris Ostrovsky wrote:
> 
> 
> On 08/03/2017 11:37 AM, Andrew Cooper wrote:
> >On 01/08/17 09:48, Yi Sun wrote:
> >>Hi all,
> >>
> >>We plan to bring a new PSR (Platform Shared Resource) feature called
> >>Intel L2 Cache Allocation Technology (L2 CAT) to Xen. It has been enabled
> >>in Linux Kernel.
> >
> >Unfortunately, the result is problematic.  This is from XenServers basic
> >sanity testing.
> >
> >(XEN) [ 1071.542192] Assertion 'socket_info' failed at psr.c:1297
> >(XEN) [ 1071.542202] ----[ Xen-4.10.0-xs139419-d  x86_64  debug=y   Not 
> >tainted ]----
> >(XEN) [ 1071.542207] CPU:    14
> >(XEN) [ 1071.542211] RIP:    e008:[<ffff82d0802a948f>] 
> >psr_domain_free+0x23/0xcc
> >(XEN) [ 1071.542223] RFLAGS: 0000000000010246   CONTEXT: hypervisor
> >(XEN) [ 1071.542229] rax: 0000000000000000   rbx: ffff8308291c8000   rcx: 
> >00000000004016c2
> >(XEN) [ 1071.542235] rdx: ffff831005317fff   rsi: 0000000000000000   rdi: 
> >ffff8308291c8000
> >(XEN) [ 1071.542241] rbp: ffff831005317da0   rsp: ffff831005317d70   r8:  
> >0000000000000000
> >(XEN) [ 1071.542246] r9:  0000000000000001   r10: 0200000000000000   r11: 
> >0000000000000001
> >(XEN) [ 1071.542252] r12: 00000000ffffffff   r13: ffff8308291c8aa8   r14: 
> >ffff8308291c8000
> >(XEN) [ 1071.542258] r15: ffff830829988000   cr0: 000000008005003b   cr4: 
> >00000000000426e0
> >(XEN) [ 1071.542263] cr3: 00000000cce80000   cr2: ffff88000234d298
> >(XEN) [ 1071.542268] ds: 002b   es: 002b   fs: 0000   gs: 0000   ss: e010   
> >cs: e008
> >(XEN) [ 1071.542276] Xen code around <ffff82d0802a948f> 
> >(psr_domain_free+0x23/0xcc):
> >(XEN) [ 1071.542280]  3d a3 70 1c 00 00 75 02 <0f> 0b 49 83 be 60 09 00 00 
> >00 0f 84 89 00 00 00
> >(XEN) [ 1071.542299] Xen stack trace from rsp=ffff831005317d70:
> >(XEN) [ 1071.542302]    ffff8308291c8000 ffff8308291c8000 00000000ffffffff 
> >ffff8308291c8aa8
> >(XEN) [ 1071.542311]    ffff8308291c8000 ffff830829988000 ffff831005317dc0 
> >ffff82d08027cc31
> >(XEN) [ 1071.542321]    ffff8308291c8aa8 ffff8300cd159000 ffff831005317df0 
> >ffff82d0802080f7
> >(XEN) [ 1071.542365]    ffff8308299b0040 0000000000000000 0000000000000000 
> >ffff831005317fff
> >(XEN) [ 1071.542372]    ffff831005317e20 ffff82d08022a86f ffff82d08059ab00 
> >ffff82d08059b200
> >(XEN) [ 1071.542380]    ffff82d08059ab00 fffffffffffffffd ffff831005317e50 
> >ffff82d08023b75f
> >(XEN) [ 1071.542389]    000000000000000e ffff8308299af670 ffff8308299af748 
> >000000000000000e
> >(XEN) [ 1071.542396]    ffff831005317e60 ffff82d08023b79f ffff831005317ee0 
> >ffff82d0802d792f
> >(XEN) [ 1071.542405]    ffff82d080365cb3 ffff82d08059b200 ffff82d08059ab00 
> >ffffffffffffffff
> >(XEN) [ 1071.542413]    ffff831005317fff 0000000000000000 0000000000000000 
> >00001fcc00001f07
> >(XEN) [ 1071.542420]    000000000000000e 000000000000000e ffff82d0805e4b10 
> >ffff831005317fff
> >(XEN) [ 1071.542428]    000000000000000e ffff830829988000 ffff831005317f10 
> >ffff82d08027b6dc
> >(XEN) [ 1071.542436]    ffff830829923000 ffff8300cd2e7000 ffff8300cd1ee000 
> >ffff830829923000
> >(XEN) [ 1071.542444]    ffff831005317da8 ffff880131e40000 0000000000000000 
> >0000000000000000
> >(XEN) [ 1071.542452]    000000000000000e ffff880131e43eb8 ffffffff81ae5878 
> >0000000000000246
> >(XEN) [ 1071.542459]    0000000000007ff0 ffff8800c653f921 0000000000000000 
> >0000000000000000
> >(XEN) [ 1071.542467]    ffffffff810013aa ffffffff81a40bc0 deadbeefdeadf00d 
> >deadbeefdeadf00d
> >(XEN) [ 1071.542475]    0000010000000000 ffffffff810013aa 000000000000e033 
> >0000000000000246
> >(XEN) [ 1071.542483]    ffff880131e43ea0 000000000000e02b c2c2c2c2c2c2c2c2 
> >c2c2c2c2c2c2c2c2
> >(XEN) [ 1071.542491]    c2c2c2c2c2c2c2c2 c2c2c2c2c2c2c2c2 c2c2c2c20000000e 
> >ffff8300cd2e7000
> >(XEN) [ 1071.542500] Xen call trace:
> >(XEN) [ 1071.542505]    [<ffff82d0802a948f>] psr_domain_free+0x23/0xcc
> >(XEN) [ 1071.542514]    [<ffff82d08027cc31>] arch_domain_destroy+0x88/0x8f
> >(XEN) [ 1071.542521]    [<ffff82d0802080f7>] 
> >domain.c#complete_domain_destroy+0x6f/0x192
> >(XEN) [ 1071.542528]    [<ffff82d08022a86f>] 
> >rcupdate.c#rcu_process_callbacks+0x141/0x1a3
> >(XEN) [ 1071.542536]    [<ffff82d08023b75f>] softirq.c#__do_softirq+0x7f/0x8a
> >(XEN) [ 1071.542542]    [<ffff82d08023b79f>] 
> >process_pending_softirqs+0x35/0x37
> >(XEN) [ 1071.542551]    [<ffff82d0802d792f>] 
> >mwait-idle.c#mwait_idle+0xfc/0x2dd
> >(XEN) [ 1071.542557]    [<ffff82d08027b6dc>] domain.c#idle_loop+0x72/0x8a
> >(XEN) [ 1071.542561]
> >(XEN) [ 1071.916649]
> >(XEN) [ 1071.918881] ****************************************
> >(XEN) [ 1071.924987] Panic on CPU 14:
> >(XEN) [ 1071.928771] Assertion 'socket_info' failed at psr.c:1297
> >(XEN) [ 1071.935265] ****************************************
> >(XEN) [ 1071.941375]
> >(XEN) [ 1071.943606] Reboot in five seconds...
> >
> >The hardware is SandyBridge-EN, which has no PSR support as far as I am 
> >aware.  As a first thought, psr_free_domain() should not be making any 
> >assertions about hardware state.
> 
> Not surprisingly, I hit this as well.
> 
> It seems to me that socket_info is set only if "psr" boot parameter
> is explicitly set *and* opt_cos_max is not sufficiently low. So
> ASSERT() should be either turned into 'if' or possibly be swapped
> with d->arch.psr_cos_ids test.
> 
Very sorry for this. As you mentioned, the 'socket_info' is allocated only if
"psr" boot parameter is set. So, I should not use "ASSERT(socket_info)" in
'psr_free_cos()' which is called by 'psr_domain_free'.

I will send an update patch out to fix this. Thanks!

> 
> -boris

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