From: "Michael S. Tsirkin" <mst@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [RFC 2/2] pc: fix QEMU crashing when more than ~50 memory hotplugged
Date: Wed, 3 Jun 2015 18:30:02 +0200 [thread overview]
Message-ID: <20150603182649-mutt-send-email-mst@redhat.com> (raw)
In-Reply-To: <556F2731.8010801@redhat.com>
On Wed, Jun 03, 2015 at 06:11:29PM +0200, Paolo Bonzini wrote:
>
>
> On 03/06/2015 17:23, Igor Mammedov wrote:
> >> > Understood now. This still should be a separate patch. I'm much more
> >> > confident with the other two (e.g. what happens if a malicious guest
> >> > writes to memory that is still MAP_NORESERVE),
> > it should get SIGSEVG due to access to PROT_NONE.
>
> QEMU doesn't get the SEGV if you do address_space_rw or
> address_space_map to unallocated space, because the empty area in the
> container is treated as MMIO.
>
> But what does vhost do if you tell it to treat the whole block as a
> single huge lump?
>
> Paolo
Guest can make vhost attempt reading or writing it.
vhost will do copy from/to user.
> >> > so feel free to post
> >> > those without RFC tag. But the vhost one really needs mst's eyes.
> > ok, I'll split it out.
> >
next prev parent reply other threads:[~2015-06-03 16:30 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-03 12:22 [Qemu-devel] [RFC 0/2] Fix QEMU crash during memory hotplug with vhost=on Igor Mammedov
2015-06-03 12:22 ` [Qemu-devel] [RFC 1/2] memory: introduce MemoryRegion container with reserved HVA range Igor Mammedov
2015-06-03 12:45 ` Paolo Bonzini
2015-06-03 13:43 ` Igor Mammedov
2015-06-03 12:22 ` [Qemu-devel] [RFC 2/2] pc: fix QEMU crashing when more than ~50 memory hotplugged Igor Mammedov
2015-06-03 12:48 ` Paolo Bonzini
2015-06-03 14:05 ` Igor Mammedov
2015-06-03 15:08 ` Paolo Bonzini
2015-06-03 15:23 ` Igor Mammedov
2015-06-03 16:11 ` Paolo Bonzini
2015-06-03 16:30 ` Michael S. Tsirkin [this message]
2015-06-03 15:05 ` [Qemu-devel] [RFC 0/2] Fix QEMU crash during memory hotplug with vhost=on Michael S. Tsirkin
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