From: Borislav Petkov <bp@alien8.de>
To: "Singh, Brijesh" <brijesh.singh@amd.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Joerg Roedel" <joro@8bytes.org>,
"Lendacky, Thomas" <Thomas.Lendacky@amd.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [Qemu-devel] [RFC PATCH v1 01/10] KVM: SVM: Add KVM_SEV SEND_START command
Date: Mon, 29 Apr 2019 18:36:02 +0200 [thread overview]
Message-ID: <20190429163602.GE2324@zn.tnic> (raw)
In-Reply-To: <2b63d983-a622-3bec-e6ac-abfd024e19c0@amd.com>
On Mon, Apr 29, 2019 at 03:01:24PM +0000, Singh, Brijesh wrote:
> Practically I don't see any reason why caller would do that but
> theoretically it can. If we cache the len then we also need to consider
> adding another flag to hint whether userspace ever requested length.
> e.g an application can compute the length of session blob by looking at
> the API version and spec and may never query the length.
>
> > I mean I'm still thinking defensively here but maybe the only thing that
> > would happen here with a bigger buffer is if the kmalloc() would fail,
> > leading to eventual failure of the migration.
> >
> > If the code limits the allocation to some sane max length, the migration
> > won't fail even if userspace gives it too big values...
So what about this? Limiting to a sane length...
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
WARNING: multiple messages have this Message-ID (diff)
From: Borislav Petkov <bp@alien8.de>
To: "Singh, Brijesh" <brijesh.singh@amd.com>
Cc: "Lendacky, Thomas" <Thomas.Lendacky@amd.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Joerg Roedel" <joro@8bytes.org>,
"x86@kernel.org" <x86@kernel.org>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Ingo Molnar" <mingo@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Thomas Gleixner" <tglx@linutronix.de>
Subject: Re: [Qemu-devel] [RFC PATCH v1 01/10] KVM: SVM: Add KVM_SEV SEND_START command
Date: Mon, 29 Apr 2019 18:36:02 +0200 [thread overview]
Message-ID: <20190429163602.GE2324@zn.tnic> (raw)
Message-ID: <20190429163602.OxKNqxJ28gfg1EhB_33BErT6pTmorQWLW84zoZIHpGQ@z> (raw)
In-Reply-To: <2b63d983-a622-3bec-e6ac-abfd024e19c0@amd.com>
On Mon, Apr 29, 2019 at 03:01:24PM +0000, Singh, Brijesh wrote:
> Practically I don't see any reason why caller would do that but
> theoretically it can. If we cache the len then we also need to consider
> adding another flag to hint whether userspace ever requested length.
> e.g an application can compute the length of session blob by looking at
> the API version and spec and may never query the length.
>
> > I mean I'm still thinking defensively here but maybe the only thing that
> > would happen here with a bigger buffer is if the kmalloc() would fail,
> > leading to eventual failure of the migration.
> >
> > If the code limits the allocation to some sane max length, the migration
> > won't fail even if userspace gives it too big values...
So what about this? Limiting to a sane length...
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2019-04-29 16:36 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-24 16:09 [Qemu-devel] [RFC PATCH v1 00/10] Add AMD SEV guest live migration support Singh, Brijesh
2019-04-24 16:09 ` Singh, Brijesh
2019-04-24 16:09 ` [Qemu-devel] [RFC PATCH v1 01/10] KVM: SVM: Add KVM_SEV SEND_START command Singh, Brijesh
2019-04-24 16:09 ` Singh, Brijesh
2019-04-26 14:10 ` Borislav Petkov
2019-04-26 14:10 ` Borislav Petkov
2019-04-26 14:29 ` Singh, Brijesh
2019-04-26 14:29 ` Singh, Brijesh
2019-04-26 20:43 ` Borislav Petkov
2019-04-26 20:43 ` Borislav Petkov
2019-04-29 15:01 ` Singh, Brijesh
2019-04-29 15:01 ` Singh, Brijesh
2019-04-29 16:36 ` Borislav Petkov [this message]
2019-04-29 16:36 ` Borislav Petkov
2019-04-29 16:43 ` Singh, Brijesh
2019-04-29 16:43 ` Singh, Brijesh
2019-04-24 16:10 ` [Qemu-devel] [RFC PATCH v1 02/10] KVM: SVM: Add KVM_SEND_UPDATE_DATA command Singh, Brijesh
2019-04-24 16:10 ` Singh, Brijesh
2019-04-26 20:31 ` Lendacky, Thomas
2019-04-26 20:31 ` Lendacky, Thomas
2019-04-29 16:54 ` Singh, Brijesh
2019-04-29 16:54 ` Singh, Brijesh
2019-04-24 16:10 ` [Qemu-devel] [RFC PATCH v1 03/10] KVM: SVM: Add KVM_SEV_SEND_FINISH command Singh, Brijesh
2019-04-24 16:10 ` Singh, Brijesh
2019-04-24 16:10 ` [Qemu-devel] [RFC PATCH v1 04/10] KVM: SVM: Add support for KVM_SEV_RECEIVE_START command Singh, Brijesh
2019-04-24 16:10 ` Singh, Brijesh
2019-04-26 21:08 ` Lendacky, Thomas
2019-04-26 21:08 ` Lendacky, Thomas
2019-04-24 16:10 ` [Qemu-devel] [RFC PATCH v1 05/10] KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command Singh, Brijesh
2019-04-24 16:10 ` Singh, Brijesh
2019-04-26 21:11 ` Lendacky, Thomas
2019-04-26 21:11 ` Lendacky, Thomas
2019-04-24 16:10 ` [Qemu-devel] [RFC PATCH v1 06/10] KVM: SVM: Add KVM_SEV_RECEIVE_FINISH command Singh, Brijesh
2019-04-24 16:10 ` Singh, Brijesh
2019-04-26 21:11 ` Lendacky, Thomas
2019-04-26 21:11 ` Lendacky, Thomas
2019-04-24 16:10 ` [Qemu-devel] [RFC PATCH v1 07/10] KVM: x86: Add AMD SEV specific Hypercall3 Singh, Brijesh
2019-04-24 16:10 ` Singh, Brijesh
2019-04-24 16:10 ` [Qemu-devel] [RFC PATCH v1 08/10] KVM: X86: Introduce KVM_HC_PAGE_ENC_STATUS hypercall Singh, Brijesh
2019-04-24 16:10 ` Singh, Brijesh
2019-04-26 21:39 ` Lendacky, Thomas
2019-04-26 21:39 ` Lendacky, Thomas
2019-05-03 14:25 ` Singh, Brijesh
2019-05-03 14:25 ` Singh, Brijesh
2019-04-24 16:10 ` [Qemu-devel] [RFC PATCH v1 09/10] KVM: x86: Introduce KVM_GET_PAGE_ENC_BITMAP ioctl Singh, Brijesh
2019-04-24 16:10 ` Singh, Brijesh
2019-04-24 16:10 ` [Qemu-devel] [RFC PATCH v1 10/10] mm: x86: Invoke hypercall when page encryption status is changed Singh, Brijesh
2019-04-24 16:10 ` Singh, Brijesh
2019-04-24 19:15 ` [Qemu-devel] [RFC PATCH v1 00/10] Add AMD SEV guest live migration support Steve Rutherford
2019-04-24 19:15 ` Steve Rutherford via Qemu-devel
2019-04-24 21:32 ` Singh, Brijesh
2019-04-24 21:32 ` Singh, Brijesh
2019-04-25 0:18 ` Steve Rutherford
2019-04-25 0:18 ` Steve Rutherford via Qemu-devel
2019-04-25 2:15 ` Singh, Brijesh
2019-04-25 2:15 ` Singh, Brijesh
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190429163602.GE2324@zn.tnic \
--to=bp@alien8.de \
--cc=Thomas.Lendacky@amd.com \
--cc=brijesh.singh@amd.com \
--cc=hpa@zytor.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=rkrcmar@redhat.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).