Messages in this thread | | | Date | Wed, 15 Mar 2023 07:40:16 +0100 | Subject | Re: [RFC PATCH V3 00/16] x86/hyperv/sev: Add AMD sev-snp enlightened guest support on hyperv | From | "Gupta, Pankaj" <> |
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Hi Tianyu,
>> Hi Tianyu, >> >> While testing the guest patches on KVM host, My guest kernel is stuck >> at early bootup. As it did not seem a hang but sort of loop where >> interrupts are getting processed from "pv_native_irq_enable" path >> repeatedly and prevent boot process to make progress IIUC. Did you >> face any such scenario in your testing? >> >> It seems to me "native_irq_enable" enable interrupts and >> "check_hv_pending_irq_enable" starts handling the interrupts (after >> disabling irqs). But "check_hv_pending_irq_enable=>do_exc_hv" can >> again call "pv_native_irq_enable" in interrupt handling path and >> execute the same loop? > > > I don't meet the issue. Thanks for report. I will double check and > report back.
Thank you!
More testing with the patches: After I commented out "do_exc_hv" from pv_native_irq_enable()->check_hv_pending_irq_enable() code path. Now, I am getting below [2] stack trace repeatedly when I dump stack.
This seems to me after IST stack return from #VC handling for "native_cpuid", paranoid_exit =>"do_exc_hv" is handling interrupts. As we don't disable interrupts in check_hv_pending()=>do_exc_hv(), so interrupts are handled continuously here. This also prevents the boot processor to make progress and stuck here.
Thoughts please? as I might be missing some important details here.
Thanks, Pankaj
[2]
[ 59.845396] Call Trace:^M [ 59.845703] <TASK>^M [ 59.845980] dump_stack_lvl+0x4d/0x67^M [ 59.846432] dump_stack+0x14/0x1a^M [ 59.846842] do_exc_hv.cold+0x22/0xfd^M [ 59.847301] check_hv_pending+0x38/0x50^M [ 59.847773] paranoid_exit+0x8/0x70^M [ 59.848205] RIP: 0010:native_cpuid+0x19/0x30^M [ 59.848729] Code: 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 49 89 f8 49 89 c9 48 89 d7 41 8b 00 48 89 e5 53 8b 0a 0f a2 <41> 89 00 89 1e 48 8b 5d f8 89 0f 41 89 11 c9 e9 f7 bc df 00 0f 1f^M [ 59.850995] RSP: 0000:ffffffffbd403e48 EFLAGS: 00010202^M [ 59.851636] RAX: 000000000100007b RBX: 0000000000000000 RCX: 0000000000000000^M [ 59.852498] RDX: 0000000000000000 RSI: ffffffffbd403e64 RDI: ffffffffbd403e68^M [ 59.853361] RBP: ffffffffbd403e50 R08: ffffffffbd403e60 R09: ffffffffbd403e6c^M [ 59.854240] R10: ffffffffbd403d10 R11: ffff9af5bff3cfe8 R12: 0000000000000056^M [ 59.855111] R13: ffff9af5bffc8e40 R14: 0000000000000000 R15: ffffffffbd41a120^M [ 59.855976] kvm_arch_para_features+0x4e/0x80^M [ 59.856511] pv_ipi_supported+0xe/0x34^M [ 59.856973] kvm_apic_init+0x12/0x3f^M [ 59.857414] apic_intr_mode_init+0x8d/0x10d^M [ 59.857939] x86_late_time_init+0x28/0x3d^M [ 59.858435] start_kernel+0x8af/0x970^M [ 59.858894] x86_64_start_reservations+0x28/0x2e^M [ 59.859461] x86_64_start_kernel+0x96/0xa0^M [ 59.859965] secondary_startup_64_no_verify+0xe5/0xeb^M [ 59.860583] </TASK>^M
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