(2011/12/02 4:42), Sasha Levin wrote: > It's enough for memory slot to be readable, as the comment above the check > states. > > A user should be able to create read-only memory slot. I submitted the original patch like you to speed up page table walking, a hot path in KVM, and Avi applied the patch with changing the VERIFY_READ to VERIFY_WRITE: on x86, both do the same check. You can see that on the commit. After that, Xiao started to write with __xxx_user() based on this check IIRC. So you should keep the code as is and change the comment if you like! Thanks, Takuya > > Cc: Avi Kivity<avi@xxxxxxxxxx> > Cc: Marcelo Tosatti<mtosatti@xxxxxxxxxx> > Cc: kvm@xxxxxxxxxxxxxxx > Signed-off-by: Sasha Levin<levinsasha928@xxxxxxxxx> > --- > virt/kvm/kvm_main.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index e289486..b92883f 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -727,7 +727,7 @@ int __kvm_set_memory_region(struct kvm *kvm, > /* We can read the guest memory with __xxx_user() later on. */ > if (user_alloc&& > ((mem->userspace_addr& (PAGE_SIZE - 1)) || > - !access_ok(VERIFY_WRITE, > + !access_ok(VERIFY_READ, > (void __user *)(unsigned long)mem->userspace_addr, > mem->memory_size))) > goto out; -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
