From: Peter Xu <peterx@redhat.com>
To: Marc Zyngier <maz@kernel.org>
Cc: kvm@vger.kernel.org, catalin.marinas@arm.com,
andrew.jones@linux.dev, will@kernel.org, shan.gavin@gmail.com,
bgardon@google.com, dmatlack@google.com, pbonzini@redhat.com,
zhenyzha@redhat.com, shuah@kernel.org,
kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH v4 3/6] KVM: arm64: Enable ring-based dirty memory tracking
Date: Tue, 27 Sep 2022 14:21:00 -0400 [thread overview]
Message-ID: <YzM/DFV1TgtyRfCA@x1n> (raw)
In-Reply-To: <86sfkc7mg8.wl-maz@kernel.org>
On Tue, Sep 27, 2022 at 01:32:07PM -0400, Marc Zyngier wrote:
> On Tue, 27 Sep 2022 12:02:52 -0400,
> Peter Xu <peterx@redhat.com> wrote:
> >
> > On Tue, Sep 27, 2022 at 08:54:36AM +0800, Gavin Shan wrote:
> > > Enable ring-based dirty memory tracking on arm64 by selecting
> > > CONFIG_HAVE_KVM_DIRTY_RING_ACQ_REL and providing the ring buffer's
> > > physical page offset (KVM_DIRTY_LOG_PAGE_OFFSET).
> > >
> > > Signed-off-by: Gavin Shan <gshan@redhat.com>
> >
> > Gavin,
> >
> > Any decision made on how to tackle with the GIC status dirty bits?
>
> Which dirty bits? Are you talking of the per-RD pending bits?
Gavin found that some dirty pfn path may not have vcpu context for aarch64
offlist.
Borrowing Gavin's trace dump:
el0t_64_sync
el0t_64_sync_handler
el0_svc
do_el0_svc
__arm64_sys_ioctl
kvm_device_ioctl
vgic_its_set_attr
vgic_its_save_tables_v0
kvm_write_guest
__kvm_write_guest_page
mark_page_dirty_in_slot
With current code it'll trigger the warning in mark_page_dirty_in_slot.
An userspace approach is doable by setting these pages as always dirty in
userspace (QEMU), but even if so IIUC we'll need to drop the warning
message in mark_page_dirty_in_slot() then we take no-vcpu dirty as no-op
and expected.
I'll leave the details to Gavin.
Thanks,
--
Peter Xu
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WARNING: multiple messages have this Message-ID (diff)
From: Peter Xu <peterx@redhat.com>
To: Marc Zyngier <maz@kernel.org>
Cc: Gavin Shan <gshan@redhat.com>,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
catalin.marinas@arm.com, bgardon@google.com, shuah@kernel.org,
andrew.jones@linux.dev, will@kernel.org, dmatlack@google.com,
pbonzini@redhat.com, zhenyzha@redhat.com, shan.gavin@gmail.com,
james.morse@arm.com, suzuki.poulose@arm.com,
alexandru.elisei@arm.com, oliver.upton@linux.dev
Subject: Re: [PATCH v4 3/6] KVM: arm64: Enable ring-based dirty memory tracking
Date: Tue, 27 Sep 2022 14:21:00 -0400 [thread overview]
Message-ID: <YzM/DFV1TgtyRfCA@x1n> (raw)
In-Reply-To: <86sfkc7mg8.wl-maz@kernel.org>
On Tue, Sep 27, 2022 at 01:32:07PM -0400, Marc Zyngier wrote:
> On Tue, 27 Sep 2022 12:02:52 -0400,
> Peter Xu <peterx@redhat.com> wrote:
> >
> > On Tue, Sep 27, 2022 at 08:54:36AM +0800, Gavin Shan wrote:
> > > Enable ring-based dirty memory tracking on arm64 by selecting
> > > CONFIG_HAVE_KVM_DIRTY_RING_ACQ_REL and providing the ring buffer's
> > > physical page offset (KVM_DIRTY_LOG_PAGE_OFFSET).
> > >
> > > Signed-off-by: Gavin Shan <gshan@redhat.com>
> >
> > Gavin,
> >
> > Any decision made on how to tackle with the GIC status dirty bits?
>
> Which dirty bits? Are you talking of the per-RD pending bits?
Gavin found that some dirty pfn path may not have vcpu context for aarch64
offlist.
Borrowing Gavin's trace dump:
el0t_64_sync
el0t_64_sync_handler
el0_svc
do_el0_svc
__arm64_sys_ioctl
kvm_device_ioctl
vgic_its_set_attr
vgic_its_save_tables_v0
kvm_write_guest
__kvm_write_guest_page
mark_page_dirty_in_slot
With current code it'll trigger the warning in mark_page_dirty_in_slot.
An userspace approach is doable by setting these pages as always dirty in
userspace (QEMU), but even if so IIUC we'll need to drop the warning
message in mark_page_dirty_in_slot() then we take no-vcpu dirty as no-op
and expected.
I'll leave the details to Gavin.
Thanks,
--
Peter Xu
next prev parent reply other threads:[~2022-09-27 18:21 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-27 0:54 [PATCH v4 0/6] KVM: arm64: Enable ring-based dirty memory tracking Gavin Shan
2022-09-27 0:54 ` Gavin Shan
2022-09-27 0:54 ` [PATCH v4 1/6] KVM: x86: Introduce KVM_REQ_RING_SOFT_FULL Gavin Shan
2022-09-27 0:54 ` Gavin Shan
2022-09-27 10:26 ` Marc Zyngier
2022-09-27 10:26 ` Marc Zyngier
2022-09-27 11:31 ` Gavin Shan
2022-09-27 11:31 ` Gavin Shan
2022-09-27 16:00 ` Peter Xu
2022-09-27 16:00 ` Peter Xu
2022-09-27 0:54 ` [PATCH v4 2/6] KVM: x86: Move declaration of kvm_cpu_dirty_log_size() to kvm_dirty_ring.h Gavin Shan
2022-09-27 0:54 ` Gavin Shan
2022-09-27 16:00 ` Peter Xu
2022-09-27 16:00 ` Peter Xu
2022-09-27 0:54 ` [PATCH v4 3/6] KVM: arm64: Enable ring-based dirty memory tracking Gavin Shan
2022-09-27 0:54 ` Gavin Shan
2022-09-27 16:02 ` Peter Xu
2022-09-27 16:02 ` Peter Xu
2022-09-27 17:32 ` Marc Zyngier
2022-09-27 17:32 ` Marc Zyngier
2022-09-27 18:21 ` Peter Xu [this message]
2022-09-27 18:21 ` Peter Xu
2022-09-27 23:47 ` Gavin Shan
2022-09-27 23:47 ` Gavin Shan
2022-09-28 8:25 ` Marc Zyngier
2022-09-28 8:25 ` Marc Zyngier
2022-09-28 14:52 ` Peter Xu
2022-09-28 14:52 ` Peter Xu
2022-09-29 9:50 ` Gavin Shan
2022-09-29 9:50 ` Gavin Shan
2022-09-29 11:31 ` Gavin Shan
2022-09-29 11:31 ` Gavin Shan
2022-09-29 14:44 ` Marc Zyngier
2022-09-29 14:44 ` Marc Zyngier
2022-09-29 14:32 ` Peter Xu
2022-09-29 14:32 ` Peter Xu
2022-09-30 9:28 ` Marc Zyngier
2022-09-30 9:28 ` Marc Zyngier
2022-09-29 14:42 ` Marc Zyngier
2022-09-29 14:42 ` Marc Zyngier
2022-10-04 4:26 ` Gavin Shan
2022-10-04 4:26 ` Gavin Shan
2022-10-04 13:26 ` Peter Xu
2022-10-04 13:26 ` Peter Xu
2022-10-04 15:45 ` Marc Zyngier
2022-10-04 15:45 ` Marc Zyngier
2022-09-29 14:34 ` Marc Zyngier
2022-09-29 14:34 ` Marc Zyngier
2022-09-27 0:54 ` [PATCH v4 4/6] KVM: selftests: Use host page size to map ring buffer in dirty_log_test Gavin Shan
2022-09-27 0:54 ` Gavin Shan
2022-09-27 0:54 ` [PATCH v4 5/6] KVM: selftests: Clear dirty ring states between two modes " Gavin Shan
2022-09-27 0:54 ` Gavin Shan
2022-09-27 0:54 ` [PATCH v4 6/6] KVM: selftests: Automate choosing dirty ring size " Gavin Shan
2022-09-27 0:54 ` Gavin Shan
2022-09-27 10:30 ` [PATCH v4 0/6] KVM: arm64: Enable ring-based dirty memory tracking Marc Zyngier
2022-09-27 10:30 ` Marc Zyngier
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