From: Paolo Bonzini <pbonzini@redhat.com>
To: Arthur Chunqi Li <yzt356@gmail.com>
Cc: kvm <kvm@vger.kernel.org>, Jan Kiszka <jan.kiszka@web.de>
Subject: Re: Calling to kvm_mmu_load
Date: Wed, 30 Oct 2013 12:44:03 +0100 [thread overview]
Message-ID: <5270F103.1030603@redhat.com> (raw)
In-Reply-To: <CABpY8MJ7hgcOv_moSqVoKfduWLXaJoSYdqUjCSgtTrz_bGXiyg@mail.gmail.com>
Il 30/10/2013 12:39, Arthur Chunqi Li ha scritto:
>> >
>> > kvm_memory_slot just maps a host userspace address range to a guest
>> > physical address range. Cooperation with Linux memory management is
>> > done with the Linux MMU notifiers. MMU notifiers let KVM know that a
>> > page has been swapped out, and KVM reacts by invalidating the shadow
>> > page tables for the corresponding guest physical address.
> So for each VM, qemu need to register its memory region and KVM stores
> this region of GPA to HVA mapping in kvm_memory_slot, and at the first
> page fault KVM uses EPT to map GPA to HPA. Am I right?
Yes.
> In this way, how is ballooning mechanism implemented in KVM memory
> management module?
Ballooning is done entirely in userspace with a madvise(MADV_DONTNEED)
call on the HVA. The userspace has its own GPA->HVA mapping that is
separate from the memslots (e.g. memory_region_find +
memory_region_get_ram_ptr in QEMU).
Paolo
next prev parent reply other threads:[~2013-10-30 11:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-21 7:56 Calling to kvm_mmu_load Arthur Chunqi Li
2013-10-23 6:21 ` Paolo Bonzini
2013-10-24 7:55 ` Arthur Chunqi Li
2013-10-25 0:43 ` Paolo Bonzini
2013-10-29 5:39 ` Arthur Chunqi Li
2013-10-29 12:55 ` Paolo Bonzini
2013-10-30 11:39 ` Arthur Chunqi Li
2013-10-30 11:44 ` Paolo Bonzini [this message]
2013-10-31 8:05 ` Arthur Chunqi Li
2013-10-31 9:52 ` Paolo Bonzini
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