From: Paolo Bonzini <pbonzini@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: X86 ML <x86@kernel.org>, Theodore Ts'o <tytso@mit.edu>,
Kees Cook <keescook@chromium.org>, kvm list <kvm@vger.kernel.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Gleb Natapov <gleb@kernel.org>, Andrew Honig <ahonig@google.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linux Virtualization <virtualization@lists.linux-foundation.org>,
Daniel Borkmann <dborkman@redhat.com>,
Bandan Das <bsd@redhat.com>,
Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
Alok Kataria <akataria@vmware.com>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: GET_RNG_SEED hypercall ABI? (Re: [PATCH v5 0/5] random,x86,kvm: Rework arch RNG seeds and get some from kvm)
Date: Fri, 29 Aug 2014 08:36:47 +0200 [thread overview]
Message-ID: <54001F7F.5030206@redhat.com> (raw)
In-Reply-To: <CALCETrVW3ZQ7C6F4tab+UrUy=bX4UepPPrhVNrDtLx=ckz2EpA@mail.gmail.com>
Il 29/08/2014 02:13, Andy Lutomirski ha scritto:
> Hmm. Then, assuming that someone manages to allocate a
> cross-hypervisor MSR number for this, what am I supposed to do in the
> KVM code? Just make it available unconditionally? I don't see why
> that wouldn't work reliably, but it seems like an odd design.
The odd part of it is what Gleb mentioned.
> Also, the one and only native feature flag I tested (rdtscp) actually
> does work: RDTSCP seems to send #UD if QEMU is passed -cpu
> host,-rdtscp.
True, and I'm not sure why. There are a couple others. I was thinking
more of things like SSE, AVX or DE (that affects the availability of a
bit in CR4).
Paolo
WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Gleb Natapov <gleb@kernel.org>,
Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
"Theodore Ts'o" <tytso@mit.edu>,
Kees Cook <keescook@chromium.org>, kvm list <kvm@vger.kernel.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Bandan Das <bsd@redhat.com>, Andrew Honig <ahonig@google.com>,
Haiyang Zhang <haiyangz@microsoft.com>, X86 ML <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linux Virtualization <virtualization@lists.linux-foundation.org>,
Daniel Borkmann <dborkman@redhat.com>,
Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Alok Kataria <akataria@vmware.com>
Subject: Re: GET_RNG_SEED hypercall ABI? (Re: [PATCH v5 0/5] random,x86,kvm: Rework arch RNG seeds and get some from kvm)
Date: Fri, 29 Aug 2014 08:36:47 +0200 [thread overview]
Message-ID: <54001F7F.5030206@redhat.com> (raw)
In-Reply-To: <CALCETrVW3ZQ7C6F4tab+UrUy=bX4UepPPrhVNrDtLx=ckz2EpA@mail.gmail.com>
Il 29/08/2014 02:13, Andy Lutomirski ha scritto:
> Hmm. Then, assuming that someone manages to allocate a
> cross-hypervisor MSR number for this, what am I supposed to do in the
> KVM code? Just make it available unconditionally? I don't see why
> that wouldn't work reliably, but it seems like an odd design.
The odd part of it is what Gleb mentioned.
> Also, the one and only native feature flag I tested (rdtscp) actually
> does work: RDTSCP seems to send #UD if QEMU is passed -cpu
> host,-rdtscp.
True, and I'm not sure why. There are a couple others. I was thinking
more of things like SSE, AVX or DE (that affects the availability of a
bit in CR4).
Paolo
next prev parent reply other threads:[~2014-08-29 6:36 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-26 23:58 GET_RNG_SEED hypercall ABI? (Re: [PATCH v5 0/5] random,x86,kvm: Rework arch RNG seeds and get some from kvm) Andy Lutomirski
2014-08-26 23:58 ` Andy Lutomirski
2014-08-27 7:00 ` Paolo Bonzini
2014-08-27 7:00 ` Paolo Bonzini
2014-08-27 7:07 ` H. Peter Anvin
2014-08-27 7:07 ` H. Peter Anvin
2014-08-28 14:17 ` Gleb Natapov
2014-08-28 14:17 ` Gleb Natapov
2014-08-28 16:22 ` Andy Lutomirski
2014-08-28 16:22 ` Andy Lutomirski
2014-08-28 19:46 ` Paolo Bonzini
2014-08-28 19:46 ` Paolo Bonzini
2014-08-29 0:13 ` Andy Lutomirski
2014-08-29 0:13 ` Andy Lutomirski
2014-08-29 6:36 ` Paolo Bonzini [this message]
2014-08-29 6:36 ` Paolo Bonzini
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