On 05/22/2018 04:32 PM, Jan Beulich wrote: >>>> On 22.05.18 at 16:50, <[email protected]> wrote: >> In fact, with `s3_fake` enabled, Xen just hangs when XPTI / BTI are >> enabled; but with it disabled, I actually get a stack trace. Serial >> output and xen-syms.map attached. > > Interesting (not sure if I simply didn't pay attention before): > > (XEN) *** DOUBLE FAULT *** > (XEN) ----[ Xen-4.11-rc x86_64 debug=y Not tainted ]---- > (XEN) CPU: 0 > (XEN) RIP: e008:[<ffff82d080378964>] handle_exception+0x9c/0xff > (XEN) RFLAGS: 0000000000010006 CONTEXT: hypervisor > (XEN) rax: ffffc900402140b8 rbx: 0000000000000000 rcx: 0000000000000005 > (XEN) rdx: 0000000000000000 rsi: 0000000000000000 rdi: 0000000000000000 > (XEN) rbp: 000036ffbfdebf27 rsp: ffffc90040214000 r8: 0000000000000000 > (XEN) r9: 0000000000000000 r10: 0000000000000000 r11: 0000000000000000 > (XEN) r12: 0000000000000000 r13: 0000000000000000 r14: ffffc90040217fff > (XEN) r15: 0000000000000000 cr0: 000000008005003b cr4: 0000000000002660 > (XEN) cr3: 000000019200a000 cr2: ffffc90040213ff8 > (XEN) fsb: 0000000000000000 gsb: ffff88003dcc0000 gss: 0000000000000000 > (XEN) ds: 002b es: 002b fs: 8e00 gs: 87c1 ss: e010 cs: e008 > (XEN) Current stack base ffffc90040210000 differs from expected > ffff8300dfa80000 > (XEN) Valid stack range: ffffc90040216000-ffffc90040218000, > sp=ffffc90040214000, tss.rsp0=ffff8300dfa87fa0 > > We're in handle_exception, but on a guest (presumably Dom0) kernel stack. > > The selector values in FS and GS are also highly suspicious. > > I can't explain either for the moment, as bypassing do_suspend_lowlevel() > ought to mean that none of TR, FS, or GS get touched at all.
Actually I didn't bypass it -- this is without s3_fake. With s3_fake it hangs but I don't get any output at all. > Looking at > the flow of execution I wonder though whether your opt_fake_s3 wasn't > better placed further down the call tree, e.g. in acpi_enter_sleep_state(). > That would cause more of the involved code path to be tested. That sounds generally useful -- I'll take a look at that. > Btw, so far you've only mentioned XPTI and BTI collectively enabled or > disabled. Have you tried with one of them on and the other off? Just tried it. bti=off crashes. xpti=off works. -George _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
