From: Sean Christopherson <seanjc@google.com>
To: Ben Gardon <bgardon@google.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>, Peter Xu <peterx@redhat.com>,
Peter Shier <pshier@google.com>,
Yulei Zhang <yulei.kernel@gmail.com>,
Wanpeng Li <kernellwp@gmail.com>,
Xiao Guangrong <xiaoguangrong.eric@gmail.com>,
Kai Huang <kai.huang@intel.com>,
Keqian Zhu <zhukeqian1@huawei.com>,
David Hildenbrand <david@redhat.com>
Subject: Re: [PATCH v4 4/7] KVM: mmu: Add slots_arch_lock for memslot arch fields
Date: Tue, 11 May 2021 18:55:37 +0000 [thread overview]
Message-ID: <YJrTKWAIanZsjAW6@google.com> (raw)
In-Reply-To: <20210511171610.170160-5-bgardon@google.com>
On Tue, May 11, 2021, Ben Gardon wrote:
> Add a new lock to protect the arch-specific fields of memslots if they
> need to be modified in a kvm->srcu read critical section. A future
> commit will use this lock to lazily allocate memslot rmaps for x86.
>
> Signed-off-by: Ben Gardon <bgardon@google.com>
> ---
> include/linux/kvm_host.h | 9 +++++++++
> virt/kvm/kvm_main.c | 31 ++++++++++++++++++++++++++-----
> 2 files changed, 35 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 8895b95b6a22..2d5e797fbb08 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -472,6 +472,15 @@ struct kvm {
> #endif /* KVM_HAVE_MMU_RWLOCK */
>
> struct mutex slots_lock;
> +
> + /*
> + * Protects the arch-specific fields of struct kvm_memory_slots in
> + * use by the VM. To be used under the slots_lock (above) or in a
> + * kvm->srcu read cirtical section where acquiring the slots_lock
^^^^^^^^
critical
> + * would lead to deadlock with the synchronize_srcu in
> + * install_new_memslots.
> + */
> + struct mutex slots_arch_lock;
> struct mm_struct *mm; /* userspace tied to this vm */
> struct kvm_memslots __rcu *memslots[KVM_ADDRESS_SPACE_NUM];
> struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
next prev parent reply other threads:[~2021-05-11 18:55 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-11 17:16 [PATCH v4 0/7] Lazily allocate memslot rmaps Ben Gardon
2021-05-11 17:16 ` [PATCH v4 1/7] KVM: x86/mmu: Deduplicate rmap freeing Ben Gardon
2021-05-11 17:16 ` [PATCH v4 2/7] KVM: x86/mmu: Factor out allocating memslot rmap Ben Gardon
2021-05-11 17:56 ` Sean Christopherson
2021-05-11 18:17 ` Ben Gardon
2021-05-11 18:56 ` David Hildenbrand
2021-05-11 17:16 ` [PATCH v4 3/7] KVM: mmu: Refactor memslot copy Ben Gardon
2021-05-11 18:47 ` Sean Christopherson
2021-05-11 17:16 ` [PATCH v4 4/7] KVM: mmu: Add slots_arch_lock for memslot arch fields Ben Gardon
2021-05-11 18:55 ` Sean Christopherson [this message]
2021-05-11 19:21 ` Sean Christopherson
2021-05-11 19:29 ` Paolo Bonzini
2021-05-11 17:16 ` [PATCH v4 5/7] KVM: x86/mmu: Add a field to control memslot rmap allocation Ben Gardon
2021-05-11 17:16 ` [PATCH v4 6/7] KVM: x86/mmu: Skip rmap operations if rmaps not allocated Ben Gardon
2021-05-11 19:51 ` Sean Christopherson
2021-05-11 17:16 ` [PATCH v4 7/7] KVM: x86/mmu: Lazily allocate memslot rmaps Ben Gardon
2021-05-11 18:57 ` Sean Christopherson
2021-05-11 20:03 ` Sean Christopherson
2021-05-11 20:04 ` Sean Christopherson
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