From: Paolo Bonzini <pbonzini@redhat.com>
To: Thomas Huth <thuth@linux.vnet.ibm.com>
Cc: cornelia.huck@de.ibm.com, borntraeger@de.ibm.com,
qemu-devel@nongnu.org, kvm@vger.kernel.org, agraf@suse.de
Subject: Re: [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory
Date: Tue, 03 Feb 2015 16:22:32 +0100 [thread overview]
Message-ID: <54D0E7B8.2060501@redhat.com> (raw)
In-Reply-To: <20150203161601.1319f7ef@oc7435384737.ibm.com>
On 03/02/2015 16:16, Thomas Huth wrote:
> Actually, I'd prefer to keep the "virtual" in the defines for the type
> of operation below: When it comes to s390 storage keys, we likely might
> need some calls for reading and writing to physical memory, too. Then
> we could simply extend this ioctl instead of inventing a new one.
Can you explain why it is necessary to read/write physical addresses
from user space? In the case of QEMU, I'm worried that you would have
to invent your own memory read/write APIs that are different from
everything else.
On real s390 zPCI, does bus-master DMA update storage keys?
>> Not really true, as you don't check it. So "It is not used by KVM with
>> the currently defined set of flags" is a better explanation.
>
> ok ... and maybe add "should be set to zero" ?
If you don't check it, it is misleading to document this.
Paolo
WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com>
To: Thomas Huth <thuth@linux.vnet.ibm.com>
Cc: cornelia.huck@de.ibm.com, borntraeger@de.ibm.com,
qemu-devel@nongnu.org, kvm@vger.kernel.org, agraf@suse.de
Subject: Re: [Qemu-devel] [PATCH RFC 1/1] KVM: s390: Add MEMOP ioctl for reading/writing guest memory
Date: Tue, 03 Feb 2015 16:22:32 +0100 [thread overview]
Message-ID: <54D0E7B8.2060501@redhat.com> (raw)
In-Reply-To: <20150203161601.1319f7ef@oc7435384737.ibm.com>
On 03/02/2015 16:16, Thomas Huth wrote:
> Actually, I'd prefer to keep the "virtual" in the defines for the type
> of operation below: When it comes to s390 storage keys, we likely might
> need some calls for reading and writing to physical memory, too. Then
> we could simply extend this ioctl instead of inventing a new one.
Can you explain why it is necessary to read/write physical addresses
from user space? In the case of QEMU, I'm worried that you would have
to invent your own memory read/write APIs that are different from
everything else.
On real s390 zPCI, does bus-master DMA update storage keys?
>> Not really true, as you don't check it. So "It is not used by KVM with
>> the currently defined set of flags" is a better explanation.
>
> ok ... and maybe add "should be set to zero" ?
If you don't check it, it is misleading to document this.
Paolo
next prev parent reply other threads:[~2015-02-03 15:22 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-03 12:11 [PATCH RFC 0/1] KVM: ioctl for reading/writing guest memory Thomas Huth
2015-02-03 12:11 ` [Qemu-devel] " Thomas Huth
2015-02-03 12:11 ` [PATCH RFC 1/1] KVM: s390: Add MEMOP " Thomas Huth
2015-02-03 12:11 ` [Qemu-devel] " Thomas Huth
2015-02-03 13:04 ` Paolo Bonzini
2015-02-03 13:04 ` [Qemu-devel] " Paolo Bonzini
2015-02-03 15:16 ` Thomas Huth
2015-02-03 15:16 ` [Qemu-devel] " Thomas Huth
2015-02-03 15:22 ` Paolo Bonzini [this message]
2015-02-03 15:22 ` Paolo Bonzini
2015-02-04 7:53 ` Thomas Huth
2015-02-04 7:53 ` [Qemu-devel] " Thomas Huth
2015-02-04 8:26 ` Christian Borntraeger
2015-02-04 8:26 ` [Qemu-devel] " Christian Borntraeger
2015-02-04 10:39 ` Paolo Bonzini
2015-02-04 10:39 ` [Qemu-devel] " Paolo Bonzini
2015-02-04 11:25 ` Christian Borntraeger
2015-02-04 11:25 ` [Qemu-devel] " Christian Borntraeger
2015-02-04 11:42 ` Paolo Bonzini
2015-02-04 11:42 ` [Qemu-devel] " Paolo Bonzini
2015-02-04 12:16 ` Christian Borntraeger
2015-02-04 12:16 ` [Qemu-devel] " Christian Borntraeger
2015-02-04 10:57 ` Thomas Huth
2015-02-04 10:57 ` [Qemu-devel] " Thomas Huth
2015-02-05 13:00 ` Cornelia Huck
2015-02-05 13:00 ` [Qemu-devel] " Cornelia Huck
2015-02-03 12:59 ` [PATCH RFC 0/1] KVM: " Paolo Bonzini
2015-02-03 12:59 ` [Qemu-devel] " Paolo Bonzini
2015-02-03 13:05 ` Christian Borntraeger
2015-02-03 13:05 ` [Qemu-devel] " Christian Borntraeger
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