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Re: [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/
From: |
Christian Borntraeger |
Subject: |
Re: [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory |
Date: |
Wed, 04 Feb 2015 12:25:04 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 |
Am 04.02.2015 um 11:39 schrieb Paolo Bonzini:
>> Conny:
>> I am asking myself, if we should explicitly add a comment in the
>> virtio-ccw spec, that all accesses are assumed to be with key 0 and
>> thus never cause key protection. The change/reference bit is set
>> by the underlying I/O or memory copy anyway.
>
> Can you explain the last sentence? :)
Whenever vhost or qemu or a finished aio request wrote content into a
virtio buffer, the HW has set the storage key for that physical page,
which makes it automatically dirty/referenced in the guest visible
storage key.
For completeness sake:
Now, if the guest does not use the storage key, but instead the new fault
based software dirty tracking, it wont notice the change bit. The guest
I/O itself when finished will mark the struct page as Dirty, just like on
x86.
Makes sense?
Christian
- [Qemu-devel] [PATCH RFC 0/1] KVM: ioctl for reading/writing guest memory, Thomas Huth, 2015/02/03
- [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory, Thomas Huth, 2015/02/03
- Re: [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory, Paolo Bonzini, 2015/02/03
- Re: [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory, Thomas Huth, 2015/02/03
- Re: [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory, Paolo Bonzini, 2015/02/03
- Re: [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory, Thomas Huth, 2015/02/04
- Re: [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory, Christian Borntraeger, 2015/02/04
- Re: [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory, Paolo Bonzini, 2015/02/04
- Re: [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory,
Christian Borntraeger <=
- Re: [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory, Paolo Bonzini, 2015/02/04
- Re: [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory, Christian Borntraeger, 2015/02/04
- Re: [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory, Thomas Huth, 2015/02/04
- Re: [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory, Cornelia Huck, 2015/02/05
Re: [Qemu-devel] [PATCH RFC 0/1] KVM: ioctl for reading/writing guest memory, Paolo Bonzini, 2015/02/03