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authorSean Christopherson <seanjc@google.com>2024-01-09 17:15:31 -0800
committerSean Christopherson <seanjc@google.com>2024-02-06 11:04:10 -0800
commit422eeb543ac99ea24b80c19492c3359696500a47 (patch)
treeac78c157c161708d94f678f0b1d952445e72b03a /virt
parent3d75b8aa5c29058a512db29da7cbee8052724157 (diff)
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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.c3
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)