From: Peter Zijlstra <peterz@infradead.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Randy Dunlap <rdunlap@infradead.org>,
Borislav Petkov <bp@alien8.de>, Juergen Gross <jgross@suse.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Stefano Stabellini <sstabellini@kernel.org>,
x86@kernel.org, linux-kernel@vger.kernel.org,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH -tip v3 1/2] x86: xen: insn: Decode Xen and KVM emulate-prefix signature
Date: Fri, 6 Sep 2019 11:15:10 +0200 [thread overview]
Message-ID: <20190906091510.GV2349@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190906175143.469287501610cbca73f0abbb@kernel.org>
On Fri, Sep 06, 2019 at 05:51:43PM +0900, Masami Hiramatsu wrote:
> On Fri, 6 Sep 2019 17:45:19 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> > >
> > > How about we make this asm/virt_prefix.h or something and include:
> > >
> > > /*
> > > * Virt escape sequences to trigger instruction emulation;
> > > * ideally these would decode to 'whole' instruction and not destroy
> > > * the instruction stream; sadly this is not true for the 'kvm' one :/
> > > */
> > >
> > > #define __XEN_EMULATE_PREFIX 0x0f,0x0b,0x78,0x65,0x6e /* ud2 ; .ascii "xen" */
> > > #define __KVM_EMULATE_PREFIX 0x0f,0x0b,0x6b,0x76,0x6d /* ud2 ; .ascii "kvm" */
>
> BTW, what should we call it, "emulate prefix" or "virt prefix"?
> "virt prefix" sounds too generic to me. So I rather like emulate_prefix.h.
Works for me; and yeah, just see what is best for the other things. I
only started down that road because the Xen and KVM 'prefixes' were
initialized so inconsistently.
next prev parent reply other threads:[~2019-09-06 9:15 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-06 1:45 [PATCH -tip v3 0/2] x86: kprobes: Prohibit kprobes on Xen/KVM emulate prefixes Masami Hiramatsu
2019-09-06 1:45 ` [PATCH -tip v3 1/2] x86: xen: insn: Decode Xen and KVM emulate-prefix signature Masami Hiramatsu
2019-09-06 7:34 ` Peter Zijlstra
2019-09-06 8:45 ` Masami Hiramatsu
2019-09-06 8:51 ` Masami Hiramatsu
2019-09-06 9:15 ` Peter Zijlstra [this message]
2019-09-06 10:28 ` Masami Hiramatsu
2019-09-06 1:45 ` [PATCH -tip v3 2/2] x86: kprobes: Prohibit probing on instruction which has emulate prefix Masami Hiramatsu
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