2015-10-12 14:09+0200, Paolo Bonzini:
> Otherwise, two copies (one of them never used and thus bogus) are
> allocated for the regular and SMM address spaces. This breaks
> SMM with EPT but without unrestricted guest support, because the
> SMM copy of the identity page map is all zeros.
(Have you found out why EPT+unrestricted didn't use the alternative SMM
mapping as well?)
> By moving the allocation to the caller we also remove the last
> vestiges of kernel-allocated memory regions (not accessible anymore
> in userspace since commit b74a07beed0e, "KVM: Remove kernel-allocated
> memory regions", 2010-06-21); that is a nice bonus.
>
> Reported-by: Alexandre DERUMIER <aderumier@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 9da0e4d5ac969909f6b435ce28ea28135a9cbd69
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
vm_mmap() leaks if __kvm_set_memory_region() fails. It's nothing new
and following process termination should take care of it,
Reviewed-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> @@ -7717,23 +7717,53 @@ void kvm_arch_sync_events(struct kvm *kvm)
> int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size)
> {
> int i, r;
> + u64 hva;
> + struct kvm_memslots *slots = kvm_memslots(kvm);
> + struct kvm_memory_slot *slot, old;
| [...]
> + slot = &slots->memslots[slots->id_to_index[id]];
This seems better written as
slot = id_to_memslot(slots, id);
(Made me remember that I want to refactor the memslot API ...)
| [...]
> + } else {
> + if (!slot->npages)
> + return 0;
> +
> + hva = 0;
> + }
> +
> + old = *slot;
(Assignment could be in the 'else' == !size branch, GCC would have fun.)
| [...]
> + if (!size) {
> + r = vm_munmap(old.userspace_addr, old.npages * PAGE_SIZE);
> + WARN_ON(r < 0);
> + }
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