From: Oliver Upton <oliver.upton@linux.dev>
To: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
Reiji Watanabe <reijiw@google.com>,
Ricardo Koller <ricarkol@google.com>,
David Matlack <dmatlack@google.com>,
Quentin Perret <qperret@google.com>,
Ben Gardon <bgardon@google.com>, Gavin Shan <gshan@redhat.com>,
Peter Xu <peterx@redhat.com>, Will Deacon <will@kernel.org>,
Sean Christopherson <seanjc@google.com>,
kvmarm@lists.linux.dev
Subject: Re: [PATCH v5 08/14] KVM: arm64: Protect stage-2 traversal with RCU
Date: Mon, 14 Nov 2022 17:42:05 +0000 [thread overview]
Message-ID: <Y3J97ZTef8HLUv4i@google.com> (raw)
In-Reply-To: <d9854277-0411-8169-9e8b-68d15e4c0248@samsung.com>
Hi Marek,
On Mon, Nov 14, 2022 at 03:29:14PM +0100, Marek Szyprowski wrote:
> This patch landed in today's linux-next (20221114) as commit
> c3119ae45dfb ("KVM: arm64: Protect stage-2 traversal with RCU").
> Unfortunately it introduces a following warning:
Thanks for the bug report :) I had failed to test nVHE in the past few
revisions of this series.
> --->8---
>
> kvm [1]: IPA Size Limit: 40 bits
> BUG: sleeping function called from invalid context at
> include/linux/sched/mm.h:274
> in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0
> preempt_count: 0, expected: 0
> RCU nest depth: 1, expected: 0
> 2 locks held by swapper/0/1:
> #0: ffff80000a8a44d0 (kvm_hyp_pgd_mutex){+.+.}-{3:3}, at:
> __create_hyp_mappings+0x80/0xc4
> #1: ffff80000a927720 (rcu_read_lock){....}-{1:2}, at:
> kvm_pgtable_walk+0x0/0x1f4
> CPU: 2 PID: 1 Comm: swapper/0 Not tainted 6.1.0-rc3+ #5918
> Hardware name: Raspberry Pi 3 Model B (DT)
> Call trace:
> dump_backtrace.part.0+0xe4/0xf0
> show_stack+0x18/0x40
> dump_stack_lvl+0x8c/0xb8
> dump_stack+0x18/0x34
> __might_resched+0x178/0x220
> __might_sleep+0x48/0xa0
> prepare_alloc_pages+0x178/0x1a0
> __alloc_pages+0x9c/0x109c
> alloc_page_interleave+0x1c/0xc4
> alloc_pages+0xec/0x160
> get_zeroed_page+0x1c/0x44
> kvm_hyp_zalloc_page+0x14/0x20
> hyp_map_walker+0xd4/0x134
> kvm_pgtable_visitor_cb.isra.0+0x38/0x5c
> __kvm_pgtable_walk+0x1a4/0x220
> kvm_pgtable_walk+0x104/0x1f4
> kvm_pgtable_hyp_map+0x80/0xc4
> __create_hyp_mappings+0x9c/0xc4
> kvm_mmu_init+0x144/0x1cc
> kvm_arch_init+0xe4/0xef4
> kvm_init+0x3c/0x3d0
> arm_init+0x20/0x30
> do_one_initcall+0x74/0x400
> kernel_init_freeable+0x2e0/0x350
> kernel_init+0x24/0x130
> ret_from_fork+0x10/0x20
> kvm [1]: Hyp mode initialized successfully
>
> --->8----
>
> I looks that more changes in the KVM code are needed to use RCU for that
> code.
Right, the specific issue is that while the stage-2 walkers preallocate
any table memory they may need, the hyp walkers do not and allocate
inline.
As hyp stage-1 is protected by a spinlock there is no actual need for
RCU in that case. I'll post something later on today that addresses the
issue.
--
Thanks,
Oliver
next prev parent reply other threads:[~2022-11-14 17:42 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-07 21:56 [PATCH v5 00/14] KVM: arm64: Parallel stage-2 fault handling Oliver Upton
2022-11-07 21:56 ` [PATCH v5 01/14] KVM: arm64: Combine visitor arguments into a context structure Oliver Upton
2022-11-09 22:23 ` Ben Gardon
2022-11-09 22:48 ` Oliver Upton
2022-11-10 0:23 ` Gavin Shan
2022-11-10 0:42 ` Oliver Upton
2022-11-10 3:40 ` Gavin Shan
2022-11-07 21:56 ` [PATCH v5 02/14] KVM: arm64: Stash observed pte value in visitor context Oliver Upton
2022-11-09 22:23 ` Ben Gardon
2022-11-10 4:55 ` Gavin Shan
2022-11-07 21:56 ` [PATCH v5 03/14] KVM: arm64: Pass mm_ops through the " Oliver Upton
2022-11-09 22:23 ` Ben Gardon
2022-11-10 5:22 ` Gavin Shan
2022-11-10 5:30 ` Gavin Shan
2022-11-07 21:56 ` [PATCH v5 04/14] KVM: arm64: Don't pass kvm_pgtable through kvm_pgtable_walk_data Oliver Upton
2022-11-09 22:23 ` Ben Gardon
2022-11-10 5:30 ` Gavin Shan
2022-11-10 5:38 ` Oliver Upton
2022-11-07 21:56 ` [PATCH v5 05/14] KVM: arm64: Add a helper to tear down unlinked stage-2 subtrees Oliver Upton
2022-11-09 22:23 ` Ben Gardon
2022-11-09 22:54 ` Oliver Upton
2022-11-07 21:56 ` [PATCH v5 06/14] KVM: arm64: Use an opaque type for pteps Oliver Upton
2022-11-09 22:23 ` Ben Gardon
2022-11-07 21:56 ` [PATCH v5 07/14] KVM: arm64: Tear down unlinked stage-2 subtree after break-before-make Oliver Upton
2022-11-09 22:24 ` Ben Gardon
2022-11-07 21:56 ` [PATCH v5 08/14] KVM: arm64: Protect stage-2 traversal with RCU Oliver Upton
2022-11-09 21:53 ` Sean Christopherson
2022-11-09 23:55 ` Oliver Upton
2022-11-15 18:47 ` Ricardo Koller
2022-11-15 18:57 ` Oliver Upton
2022-11-09 22:25 ` Ben Gardon
2022-11-10 13:34 ` Marc Zyngier
[not found] ` <CGME20221114142915eucas1p258f3ca2c536bde712c068e96851468fd@eucas1p2.samsung.com>
2022-11-14 14:29 ` Marek Szyprowski
2022-11-14 17:42 ` Oliver Upton [this message]
2022-12-05 5:51 ` Mingwei Zhang
2022-12-05 7:47 ` Oliver Upton
2022-11-07 21:56 ` [PATCH v5 09/14] KVM: arm64: Atomically update stage 2 leaf attributes in parallel walks Oliver Upton
2022-11-09 22:26 ` Ben Gardon
2022-11-09 22:42 ` Sean Christopherson
2022-11-09 23:00 ` Ben Gardon
2022-11-10 13:40 ` Marc Zyngier
2022-11-07 21:56 ` [PATCH v5 10/14] KVM: arm64: Split init and set for table PTE Oliver Upton
2022-11-09 22:26 ` Ben Gardon
2022-11-09 23:00 ` Oliver Upton
2022-11-07 21:58 ` [PATCH v5 11/14] KVM: arm64: Make block->table PTE changes parallel-aware Oliver Upton
2022-11-09 22:26 ` Ben Gardon
2022-11-09 23:03 ` Oliver Upton
2022-11-07 21:59 ` [PATCH v5 12/14] KVM: arm64: Make leaf->leaf " Oliver Upton
2022-11-09 22:26 ` Ben Gardon
2022-11-07 22:00 ` [PATCH v5 13/14] KVM: arm64: Make table->block " Oliver Upton
2022-11-07 22:00 ` [PATCH v5 14/14] KVM: arm64: Handle stage-2 faults in parallel Oliver Upton
2022-11-11 15:47 ` [PATCH v5 00/14] KVM: arm64: Parallel stage-2 fault handling Marc Zyngier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Y3J97ZTef8HLUv4i@google.com \
--to=oliver.upton@linux.dev \
--cc=alexandru.elisei@arm.com \
--cc=bgardon@google.com \
--cc=dmatlack@google.com \
--cc=gshan@redhat.com \
--cc=james.morse@arm.com \
--cc=kvm@vger.kernel.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=kvmarm@lists.linux.dev \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=m.szyprowski@samsung.com \
--cc=maz@kernel.org \
--cc=peterx@redhat.com \
--cc=qperret@google.com \
--cc=reijiw@google.com \
--cc=ricarkol@google.com \
--cc=seanjc@google.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).