From: Jan Kiszka <jan.kiszka@siemens.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Jim Mattson <jmattson@google.com>,
Liran Alon <liran.alon@oracle.com>,
KarimAllah Ahmed <karahmed@amazon.de>, kvm <kvm@vger.kernel.org>
Subject: KVM_SET_NESTED_STATE not yet stable
Date: Mon, 8 Jul 2019 22:39:40 +0200 [thread overview]
Message-ID: <9eb4dd9f-65e5-627d-b288-e5fe8ade0963@siemens.com> (raw)
Hi all,
it seems the "new" KVM_SET_NESTED_STATE interface has some remaining
robustness issues. The most urgent one: With the help of latest QEMU
master that uses this interface, you can easily crash the host. You just
need to start qemu-system-x86 -enable-kvm in L1 and then hard-reset L1.
The host CPU that ran this will stall, the system will freeze soon.
I've also seen a pattern with my Jailhouse test VM where I seems to get
stuck in a loop between L1 and L2:
qemu-system-x86-6660 [007] 398.691401: kvm_nested_vmexit: rip 7fa9ee5224e4 reason IO_INSTRUCTION info1 5658000b info2 0 int_info 0 int_info_err 0
qemu-system-x86-6660 [007] 398.691402: kvm_fpu: unload
qemu-system-x86-6660 [007] 398.691403: kvm_userspace_exit: reason KVM_EXIT_IO (2)
qemu-system-x86-6660 [007] 398.691440: kvm_fpu: load
qemu-system-x86-6660 [007] 398.691441: kvm_pio: pio_read at 0x5658 size 4 count 1 val 0x4
qemu-system-x86-6660 [007] 398.691443: kvm_mmu_get_page: existing sp gfn 3a22e 1/4 q3 direct --x !pge !nxe root 6 sync
qemu-system-x86-6660 [007] 398.691444: kvm_entry: vcpu 3
qemu-system-x86-6660 [007] 398.691475: kvm_exit: reason IO_INSTRUCTION rip 0x7fa9ee5224e4 info 5658000b 0
qemu-system-x86-6660 [007] 398.691476: kvm_nested_vmexit: rip 7fa9ee5224e4 reason IO_INSTRUCTION info1 5658000b info2 0 int_info 0 int_info_err 0
qemu-system-x86-6660 [007] 398.691477: kvm_fpu: unload
qemu-system-x86-6660 [007] 398.691478: kvm_userspace_exit: reason KVM_EXIT_IO (2)
qemu-system-x86-6660 [007] 398.691526: kvm_fpu: load
qemu-system-x86-6660 [007] 398.691527: kvm_pio: pio_read at 0x5658 size 4 count 1 val 0x4
qemu-system-x86-6660 [007] 398.691529: kvm_mmu_get_page: existing sp gfn 3a22e 1/4 q3 direct --x !pge !nxe root 6 sync
qemu-system-x86-6660 [007] 398.691530: kvm_entry: vcpu 3
qemu-system-x86-6660 [007] 398.691533: kvm_exit: reason IO_INSTRUCTION rip 0x7fa9ee5224e4 info 5658000b 0
qemu-system-x86-6660 [007] 398.691534: kvm_nested_vmexit: rip 7fa9ee5224e4 reason IO_INSTRUCTION info1 5658000b info2 0 int_info 0 int_info_err 0
These issues disappear when going from ebbfef2f back to 6cfd7639 (both
with build fixes) in QEMU. Host kernels tested: 5.1.16 (distro) and 5.2
(vanilla).
Jan
--
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux
next reply other threads:[~2019-07-08 20:53 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-08 20:39 Jan Kiszka [this message]
2019-07-10 15:24 ` KVM_SET_NESTED_STATE not yet stable Raslan, KarimAllah
2019-07-10 16:05 ` Jan Kiszka
2019-07-10 20:31 ` Jan Kiszka
2019-07-10 21:14 ` Jan Kiszka
2019-07-11 11:37 ` Ralf Ramsauer
2019-07-11 17:30 ` Paolo Bonzini
2019-07-19 16:38 ` Paolo Bonzini
2019-07-21 9:05 ` Jan Kiszka
2019-07-22 15:10 ` Ralf Ramsauer
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