From: Wanpeng Li <kernellwp@gmail.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: LKML <linux-kernel@vger.kernel.org>, kvm <kvm@vger.kernel.org>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Brijesh Singh <brijesh.singh@amd.com>
Subject: Re: [PATCH v2] KVM: kvmclock: Fix vCPUs > 64 can't be online/hotpluged
Date: Wed, 27 Jan 2021 08:28:26 +0800 [thread overview]
Message-ID: <CANRm+CwcrrTC8w5h3GrszOcu0H2vtcXNi0GD1iXc6O4-x_Ms0A@mail.gmail.com> (raw)
In-Reply-To: <146d2a3f-88db-ff80-29d6-de2b22efdf61@redhat.com>
On Wed, 27 Jan 2021 at 01:26, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 26/01/21 02:28, Wanpeng Li wrote:
> > ping，
> > On Mon, 18 Jan 2021 at 17:08, Wanpeng Li <kernellwp@gmail.com> wrote:
> >>
> >> From: Wanpeng Li <wanpengli@tencent.com>
> >>
> >> The per-cpu vsyscall pvclock data pointer assigns either an element of the
> >> static array hv_clock_boot (#vCPU <= 64) or dynamically allocated memory
> >> hvclock_mem (vCPU > 64), the dynamically memory will not be allocated if
> >> kvmclock vsyscall is disabled, this can result in cpu hotpluged fails in
> >> kvmclock_setup_percpu() which returns -ENOMEM. This patch fixes it by not
> >> assigning vsyscall pvclock data pointer if kvmclock vdso_clock_mode is not
> >> VDSO_CLOCKMODE_PVCLOCK.
>
> I am sorry, I still cannot figure out this patch.
>
> Is hotplug still broken if kvm vsyscall is enabled?
Just when kvm vsyscall is disabled. :)
# lscpu
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 88
On-line CPU(s) list: 0-63
Off-line CPU(s) list: 64-87
# cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-5.10.0-rc3-tlinux2-0050+ root=/dev/mapper/cl-root
ro rd.lvm.lv=cl/root rhgb quiet console=ttyS0 LANG=en_US
.UTF-8 no-kvmclock-vsyscall
# echo 1 > /sys/devices/system/cpu/cpu76/online
-bash: echo: write error: Cannot allocate memory
Wanpeng
next prev parent reply other threads:[~2021-01-27 7:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-18 9:07 [PATCH v2] KVM: kvmclock: Fix vCPUs > 64 can't be online/hotpluged Wanpeng Li
2021-01-26 1:28 ` Wanpeng Li
2021-01-26 17:26 ` Paolo Bonzini
2021-01-27 0:28 ` Wanpeng Li [this message]
2021-01-28 7:41 ` Wanpeng Li
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