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| author | Sean Christopherson <seanjc@google.com> | 2024-01-09 17:15:31 -0800 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-02-06 11:04:10 -0800 |
| commit | 422eeb543ac99ea24b80c19492c3359696500a47 (patch) | |
| tree | ac78c157c161708d94f678f0b1d952445e72b03a /virt | |
| parent | 3d75b8aa5c29058a512db29da7cbee8052724157 (diff) | |
| download | linux-422eeb543ac99ea24b80c19492c3359696500a47.tar.gz linux-422eeb543ac99ea24b80c19492c3359696500a47.tar.bz2 linux-422eeb543ac99ea24b80c19492c3359696500a47.zip | |
KVM: Put mm immediately after async #PF worker completes remote gup()
Put the async #PF worker's reference to the VM's address space as soon as
the worker is done with the mm. This will allow deferring getting a
reference to the worker itself without having to track whether or not
getting a reference succeeded.
Note, if the vCPU is still alive, there is no danger of the worker getting
stuck with tearing down the host page tables, as userspace also holds a
reference (obviously), i.e. there is no risk of delaying the page-present
notification due to triggering the slow path in mmput().
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20240110011533.503302-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/async_pf.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c index 28658b9e0d96..85acc9e824b9 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -64,6 +64,7 @@ static void async_pf_execute(struct work_struct *work) get_user_pages_remote(mm, addr, 1, FOLL_WRITE, NULL, &locked); if (locked) mmap_read_unlock(mm); + mmput(mm); if (IS_ENABLED(CONFIG_KVM_ASYNC_PF_SYNC)) kvm_arch_async_page_present(vcpu, apf); @@ -85,8 +86,6 @@ static void async_pf_execute(struct work_struct *work) trace_kvm_async_pf_completed(addr, cr2_or_gpa); __kvm_vcpu_wake_up(vcpu); - - mmput(mm); } static void kvm_flush_and_free_async_pf_work(struct kvm_async_pf *work) |