[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: S3 resume issue in xstate_init
On 17.08.2021 13:44, Marek Marczykowski-Górecki wrote: > On Tue, Aug 17, 2021 at 12:14:36PM +0100, Andrew Cooper wrote: >> On 17/08/2021 12:02, Marek Marczykowski-Górecki wrote: >>> On Tue, Aug 17, 2021 at 03:25:21AM +0200, Marek Marczykowski-Górecki wrote: >>>> Hi, >>>> >>>> I've got another S3 issue: >>>> >>>> (XEN) Preparing system for ACPI S3 state. >>>> (XEN) Disabling non-boot CPUs ... >>>> (XEN) Broke affinity for IRQ1, new: ffff >>>> (XEN) Broke affinity for IRQ16, new: ffff >>>> (XEN) Broke affinity for IRQ9, new: ffff >>>> (XEN) Broke affinity for IRQ139, new: ffff >>>> (XEN) Broke affinity for IRQ8, new: ffff >>>> (XEN) Broke affinity for IRQ14, new: ffff >>>> (XEN) Broke affinity for IRQ20, new: ffff >>>> (XEN) Broke affinity for IRQ137, new: ffff >>>> (XEN) Broke affinity for IRQ138, new: ffff >>>> (XEN) Entering ACPI S3 state. >>>> (XEN) mce_intel.c:773: MCA Capability: firstbank 0, extended MCE MSR 0, >>>> BCAST, CMCI >>>> (XEN) CPU0 CMCI LVT vector (0xf1) already installed >>>> (XEN) Finishing wakeup from ACPI S3 state. >>>> (XEN) microcode: CPU0 updated from revision 0xca to 0xea, date = 2021-01-05 >>>> (XEN) xstate: size: 0x440 (uncompressed 0x440) and states: 0x1f >>>> (XEN) Enabling non-boot CPUs ... >>>> (XEN) xstate: size: 0x440 (uncompressed 0x240) and states: 0x1f >>>> (XEN) Xen BUG at xstate.c:673 >>>> (XEN) ----[ Xen-4.16-unstable x86_64 debug=y Not tainted ]---- >>>> (XEN) CPU: 1 >>>> (XEN) RIP: e008:[<ffff82d040350ee4>] xstate_init+0x24b/0x2ff >>>> (XEN) RFLAGS: 0000000000010087 CONTEXT: hypervisor >>>> (XEN) rax: 0000000000000240 rbx: 000000000000001f rcx: 0000000000000440 >>>> (XEN) rdx: 0000000000000001 rsi: 000000000000000a rdi: 000000000000001f >>>> (XEN) rbp: ffff83025dc9fd38 rsp: ffff83025dc9fd20 r8: 0000000000000001 >>>> (XEN) r9: ffff83025dc9fc88 r10: 0000000000000001 r11: 0000000000000001 >>>> (XEN) r12: ffff83025dc9fd80 r13: 000000000000001f r14: 0000000000000001 >>>> (XEN) r15: 0000000000000000 cr0: 000000008005003b cr4: 00000000003526e0 >>>> (XEN) cr3: 0000000049656000 cr2: 0000000000000000 >>>> (XEN) fsb: 0000000000000000 gsb: 0000000000000000 gss: 0000000000000000 >>>> (XEN) ds: 0000 es: 0000 fs: 0000 gs: 0000 ss: 0000 cs: e008 >>>> (XEN) Xen code around <ffff82d040350ee4> (xstate_init+0x24b/0x2ff): >>>> (XEN) ff e9 a2 00 00 00 0f 0b <0f> 0b 89 f8 89 f1 0f a2 89 f2 4c 8b 0d cb >>>> b4 0f >>>> (XEN) Xen stack trace from rsp=ffff83025dc9fd20: >>>> (XEN) 0000000000000240 ffff83025dc9fd80 0000000000000001 >>>> ffff83025dc9fd70 >>>> (XEN) ffff82d04027e7a1 000000004035a7f1 7ffafbbf01100800 >>>> 00000000bfebfbff >>>> (XEN) 0000000000000001 00000000000000c8 ffff83025dc9feb8 >>>> ffff82d0402e43ce >>>> (XEN) 000000160a9e0106 bfebfbff80000008 2c1008007ffaf3bf >>>> 0000000f00000121 >>>> (XEN) 00000000029c6fbf 0000000000000100 000000009c002e00 >>>> 02afcd7f00000000 >>>> (XEN) 756e654700000000 6c65746e49656e69 65746e4904b21920 >>>> 726f43202952286c >>>> (XEN) 376920294d542865 432048303537382d 322e322040205550 >>>> 000000007a484730 >>>> (XEN) ffff830000000000 ffff83025dc9fe18 00002400402e8e0b >>>> 000000085dc9fe30 >>>> (XEN) 00000002402e9f21 0000000000000001 ffffffff00000000 >>>> ffff82d0402e0040 >>>> (XEN) 00000000003526e0 ffff83025dc9fe68 ffff82d04027bd15 >>>> 0000000000000001 >>>> (XEN) ffff8302590a0000 0000000000000000 00000000000000c8 >>>> 0000000000000001 >>>> (XEN) 0000000000000001 ffff83025dc9feb8 ffff82d0402e32b7 >>>> 0000000000000001 >>>> (XEN) 0000000000000001 00000000000000c8 0000000000000001 >>>> ffff83025dc9fee8 >>>> (XEN) ffff82d04030e401 0000000000000001 0000000000000000 >>>> 0000000000000000 >>>> (XEN) 0000000000000000 0000000000000000 ffff82d040200122 >>>> 0800002000000002 >>>> (XEN) 0100000400010000 0000002000000000 2000000000100000 >>>> 0000001000000000 >>>> (XEN) 2000000000000000 0000000029000000 0000008000000000 >>>> 00110000a0000000 >>>> (XEN) 8000000080000000 4000000000000008 0000100000000000 >>>> 0200000040000080 >>>> (XEN) 0004000000000000 0000010000000002 0400002030000000 >>>> 0000000060000000 >>>> (XEN) 0400001000010000 0000000010000000 0000004010000000 >>>> 0000000000000000 >>>> (XEN) Xen call trace: >>>> (XEN) [<ffff82d040350ee4>] R xstate_init+0x24b/0x2ff >>>> (XEN) [<ffff82d04027e7a1>] F identify_cpu+0x318/0x4af >>>> (XEN) [<ffff82d0402e43ce>] F recheck_cpu_features+0x1f/0x72 >>>> (XEN) [<ffff82d04030e401>] F start_secondary+0x255/0x38a >>>> (XEN) [<ffff82d040200122>] F __high_start+0x82/0x91 >>>> (XEN) >>>> (XEN) >>>> (XEN) **************************************** >>>> (XEN) Panic on CPU 1: >>>> (XEN) Xen BUG at xstate.c:673 >>>> (XEN) **************************************** >>>> (XEN) >>>> (XEN) Reboot in five seconds... >>>> >>>> This is with added debug patch: >>>> >>>> diff --git a/xen/arch/x86/xstate.c b/xen/arch/x86/xstate.c >>>> index 6aaf9a2f1546..7873a21b356a 100644 >>>> --- a/xen/arch/x86/xstate.c >>>> +++ b/xen/arch/x86/xstate.c >>>> @@ -668,6 +668,8 @@ void xstate_init(struct cpuinfo_x86 *c) >>>> else >>>> { >>>> BUG_ON(xfeature_mask != feature_mask); >>>> + printk("xstate: size: %#x (uncompressed %#x) and states: >>>> %#"PRIx64"\n", >>>> + xsave_cntxt_size, hw_uncompressed_size(feature_mask), >>>> feature_mask); >>>> BUG_ON(xsave_cntxt_size != hw_uncompressed_size(feature_mask)); >>>> } >>>> >>>> >>>> As can be seen above - the xsave size differs between BSP and other >>>> CPU(s) - likely because of (not) loaded ucode update there. >>>> I guess it's a matter of moving ucode loading somewhere else, right? >>> >>> Few more data points: >>> >>> 1. The CPU is i7-8750H (family 6, model 158, stepping 10). >>> 2. I do have "smt=off" on the Xen cmdline, if that matters. >> >> As a datapoint, it would be interesting to confirm what the behaviour is >> with SMT enabled. >> >> I'd expect it not to make a difference, because smt=off is a purely Xen >> construct and doesn't change the hardware configuration. > > Uhm, changing to smt=on actually _did_ change it. Now it doesn't crash! > > Let me add CPU number to the above printk - is smp_processor_id() the > thing I want? > With that, I get: > https://gist.github.com/marmarek/ae604a1e5cf49639a1eec9e220c037ca > Note that at boot all CPUs reports 0x440 (but only later are parked). And for a feature mask of 0x1f only 0x440 can possibly be correct. I'm kind of guessing that set_xcr0() mistakenly skips the actual XCR0 write, due to the cached value matching the to-be-written one, yet the cache having gone stale across S3. I think this is to be expected for previously parked CPUs, as those don't have their per-CPU data de-allocated (and hence also not re-setup, and thus also not starting out as zero). I guess an easy fix would be to write 0 to this_cpu(xcr0) directly early in xstate_init(), maybe in an "else" to the early "if ( bsp )". I'm not sure though this would be a good fix longer term, as there might easily be other similar issues elsewhere. IOW we may need to see whether per-CPU data initialization wouldn't want changing. Jan
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