Messages in this thread Patch in this message | | | Date | Sun, 12 Mar 2023 10:12:29 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH 1/2] KVM: Use syscore_ops instead of reboot_notifier to hook restart/shutdown |
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On Fri, 10 Mar 2023 22:14:13 +0000, Sean Christopherson <seanjc@google.com> wrote: > > Use syscore_ops.shutdown to disable hardware virtualization during a > reboot instead of using the dedicated reboot_notifier so that KVM disables > virtualization _after_ system_state has been updated. This will allow > fixing a race in KVM's handling of a forced reboot where KVM can end up > enabling hardware virtualization between kernel_restart_prepare() and > machine_restart(). > > Cc: Marc Zyngier <maz@kernel.org> > Cc: Oliver Upton <oliver.upton@linux.dev> > Cc: James Morse <james.morse@arm.com> > Cc: Suzuki K Poulose <suzuki.poulose@arm.com> > Cc: Zenghui Yu <yuzenghui@huawei.com> > Cc: kvmarm@lists.linux.dev > Cc: Huacai Chen <chenhuacai@kernel.org> > Cc: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com> > Cc: Anup Patel <anup@brainfault.org> > Cc: Atish Patra <atishp@atishpatra.org> > Cc: kvm-riscv@lists.infradead.org > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > virt/kvm/kvm_main.c | 14 +++----------- > 1 file changed, 3 insertions(+), 11 deletions(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index d255964ec331..6cdfbb2c641b 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -5211,8 +5211,7 @@ static int hardware_enable_all(void) > return r; > } > > -static int kvm_reboot(struct notifier_block *notifier, unsigned long val, > - void *v) > +static void kvm_reboot(void) > { > /* > * Some (well, at least mine) BIOSes hang on reboot if > @@ -5223,14 +5222,8 @@ static int kvm_reboot(struct notifier_block *notifier, unsigned long val, > pr_info("kvm: exiting hardware virtualization\n"); > kvm_rebooting = true; > on_each_cpu(hardware_disable_nolock, NULL, 1); > - return NOTIFY_OK; > } > > -static struct notifier_block kvm_reboot_notifier = { > - .notifier_call = kvm_reboot, > - .priority = 0, > -}; > - > static int kvm_suspend(void) > { > /* > @@ -5261,6 +5254,8 @@ static void kvm_resume(void) > static struct syscore_ops kvm_syscore_ops = { > .suspend = kvm_suspend, > .resume = kvm_resume, > + .shutdown = kvm_reboot, > +
nit: consider renaming the kvm_reboot to kvm_shutdown to match the syscore structure, and drop the spurious blank line.
M.
-- Without deviation from the norm, progress is not possible.
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