* RE: General KVM/QEMU VM debugging techniques [not found] <SJ0PR02MB886210F928C7CD01DFAD5FD0FEE09@SJ0PR02MB8862.namprd02.prod.outlook.com> @ 2022-04-01 23:50 ` Kallol Biswas [C] 2022-04-04 12:36 ` Igor Mammedov 0 siblings, 1 reply; 3+ messages in thread From: Kallol Biswas [C] @ 2022-04-01 23:50 UTC (permalink / raw) To: kvm@vger.kernel.org Hi, We are observing a problem with CPU hotplug. If secureboot option is enabled under UEFI and then if we try to do CPU hotplug the VM crashes/just reboots. No crash dump is generated, no panic message, just VM restarts. Issue seems like: https://bugzilla.redhat.com/show_bug.cgi?id=1834250 What are the debugging techniques we can apply to halt the VM and examine what's going on? VM has been configured with crash dump. Nucleodyne at Nutanix 408-718-8164 ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: General KVM/QEMU VM debugging techniques 2022-04-01 23:50 ` General KVM/QEMU VM debugging techniques Kallol Biswas [C] @ 2022-04-04 12:36 ` Igor Mammedov 2022-04-04 13:01 ` Laszlo Ersek 0 siblings, 1 reply; 3+ messages in thread From: Igor Mammedov @ 2022-04-04 12:36 UTC (permalink / raw) To: Kallol Biswas [C]; +Cc: kvm@vger.kernel.org, lersek On Fri, 1 Apr 2022 23:50:16 +0000 "Kallol Biswas [C]" <kallol.biswas@nutanix.com> wrote: > Hi, > We are observing a problem with CPU hotplug. > > If secureboot option is enabled under UEFI and then if we try to do CPU hotplug the VM crashes/just reboots. > > No crash dump is generated, no panic message, just VM restarts. Issue seems like: > https://bugzilla.redhat.com/show_bug.cgi?id=1834250 CPU hotplug with SMM (for q35) was merged in QEMU-5.2 and unplug part in 6.0, you also need a matching OVMF build to make it work. Later upto 6.2 (included) there were minor fixes dealing with incorrect configs. > What are the debugging techniques we can apply to halt the VM and examine what's going on? > VM has been configured with crash dump. I'd start with https://www.linux-kvm.org/page/Tracing to find out when it goes south. > Nucleodyne at Nutanix > 408-718-8164 > ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: General KVM/QEMU VM debugging techniques 2022-04-04 12:36 ` Igor Mammedov @ 2022-04-04 13:01 ` Laszlo Ersek 0 siblings, 0 replies; 3+ messages in thread From: Laszlo Ersek @ 2022-04-04 13:01 UTC (permalink / raw) To: Igor Mammedov, Kallol Biswas [C]; +Cc: kvm@vger.kernel.org, Gerd Hoffmann On 04/04/22 14:36, Igor Mammedov wrote: > On Fri, 1 Apr 2022 23:50:16 +0000 > "Kallol Biswas [C]" <kallol.biswas@nutanix.com> wrote: > >> Hi, >> We are observing a problem with CPU hotplug. >> >> If secureboot option is enabled under UEFI and then if we try to do CPU hotplug the VM crashes/just reboots. >> >> No crash dump is generated, no panic message, just VM restarts. Issue seems like: >> https://bugzilla.redhat.com/show_bug.cgi?id=1834250 > > CPU hotplug with SMM (for q35) was merged in QEMU-5.2 > and unplug part in 6.0, you also need a matching OVMF build > to make it work. Later upto 6.2 (included) there were minor > fixes dealing with incorrect configs. > >> What are the debugging techniques we can apply to halt the VM and examine what's going on? >> VM has been configured with crash dump. > > I'd start with https://www.linux-kvm.org/page/Tracing > > to find out when it goes south. > >> Nucleodyne at Nutanix >> 408-718-8164 >> > Also don't forget to build OVMF with DEBUG_VERBOSE (set gEfiMdePkgTokenSpaceGuid.PcdDebugPrintErrorLevel to 0x8040004F), and to capture the OVMF debug log (-debugcon file:debug.log -global isa-debugcon.iobase=0x402). Laszlo ^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-04-01 23:50 ` General KVM/QEMU VM debugging techniques Kallol Biswas [C]
2022-04-04 12:36 ` Igor Mammedov
2022-04-04 13:01 ` Laszlo Ersek
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