[RFC v2 PATCH 13/13] KVM: Enable memfd based page invalidation/fallocate
From: Chao Peng <hidden>
Date: 2021-11-19 13:50:24
Also in:
kvm, linux-fsdevel, lkml, qemu-devel
Subsystem:
kernel virtual machine (kvm), the rest · Maintainers:
Paolo Bonzini, Linus Torvalds
Since the memory backing store does not get notified when VM is destroyed so need check if VM is still live in these callbacks. Signed-off-by: Yu Zhang <redacted> Signed-off-by: Chao Peng <redacted> --- virt/kvm/memfd.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)
diff --git a/virt/kvm/memfd.c b/virt/kvm/memfd.c
index bd930dcb455f..bcfdc685ce22 100644
--- a/virt/kvm/memfd.c
+++ b/virt/kvm/memfd.c@@ -12,16 +12,38 @@ #include <linux/memfd.h> const static struct guest_mem_ops *memfd_ops; +static bool vm_is_dead(struct kvm *vm) +{ + struct kvm *kvm; + + list_for_each_entry(kvm, &vm_list, vm_list) { + if (kvm == vm) + return false; + } + + return true; +} + static void memfd_invalidate_page_range(struct inode *inode, void *owner, pgoff_t start, pgoff_t end) { //!!!We can get here after the owner no longer exists + if (vm_is_dead(owner)) + return; + + kvm_memfd_invalidate_range(owner, inode, start >> PAGE_SHIFT, + end >> PAGE_SHIFT); } static void memfd_fallocate(struct inode *inode, void *owner, pgoff_t start, pgoff_t end) { //!!!We can get here after the owner no longer exists + if (vm_is_dead(owner)) + return; + + kvm_memfd_fallocate_range(owner, inode, start >> PAGE_SHIFT, + end >> PAGE_SHIFT); } static const struct guest_ops memfd_notifier = {
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2.17.1