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From: "Luis R. Rodriguez" <mcgrof@suse.com>
To: David Vrabel <david.vrabel@citrix.com>
Cc: "Luis R. Rodriguez" <mcgrof@do-not-panic.com>,
konrad.wilk@oracle.com, boris.ostrovsky@oracle.com,
xen-devel@lists.xenproject.org, Borislav Petkov <bp@suse.de>,
kvm@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org, rostedt@goodmis.org,
Andy Lutomirski <luto@amacapital.net>,
Ingo Molnar <mingo@redhat.com>, Jan Beulich <JBeulich@suse.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Thomas Gleixner <tglx@linutronix.de>,
paulmck@linux.vnet.ibm.com
Subject: Re: [Xen-devel] [PATCH v5 1/2] xen: add xen_is_preemptible_hypercall()
Date: Tue, 3 Feb 2015 19:03:34 +0100 [thread overview]
Message-ID: <20150203180334.GT19988@wotan.suse.de> (raw)
In-Reply-To: <54D0AB6B.9060909@citrix.com>
On Tue, Feb 03, 2015 at 11:05:15AM +0000, David Vrabel wrote:
> On 27/01/15 01:51, Luis R. Rodriguez wrote:
> >
> > +#ifndef CONFIG_PREEMPT
> > +extern struct { char _entry[32]; } preemptible_hypercall_page[];
> > +
> > +static inline bool xen_is_preemptible_hypercall(struct pt_regs *regs)
> > +{
> > + return !user_mode_vm(regs) &&
> > + regs->ip >= (unsigned long)preemptible_hypercall_page &&
> > + regs->ip < (unsigned long)preemptible_hypercall_page + PAGE_SIZE;
>
> I asked for this test to be optimized.
>
> return (regs->ip >> PAGE_SHIFT)
> == ((unsigned long)preemptible_hypercall_page >> PAGE_SHIFT)
> && !user_mode_vm(regs);
It didn't seem you were so sure about it and I asked some
clarifications about it but you had not replied:
http://www.gossamer-threads.com/lists/xen/devel/363565?page=last
Luis
next prev parent reply other threads:[~2015-02-03 18:03 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-27 1:51 [PATCH v5 0/2] x86/xen: add xen hypercall preemption Luis R. Rodriguez
2015-01-27 1:51 ` [PATCH v5 1/2] xen: add xen_is_preemptible_hypercall() Luis R. Rodriguez
2015-02-03 11:05 ` [Xen-devel] " David Vrabel
2015-02-03 18:03 ` Luis R. Rodriguez [this message]
2015-01-27 1:51 ` [PATCH v5 2/2] x86/xen: allow privcmd hypercalls to be preempted on 64-bit Luis R. Rodriguez
2015-01-27 8:35 ` Jan Beulich
2015-01-27 10:01 ` [Xen-devel] " Andrew Cooper
2015-01-27 10:06 ` David Vrabel
2015-01-27 20:12 ` Luis R. Rodriguez
2015-01-29 20:35 ` Luis R. Rodriguez
2015-02-03 0:24 ` Luis R. Rodriguez
2015-02-03 9:58 ` David Vrabel
2015-02-05 12:47 ` [Xen-devel] [PATCH v5 0/2] x86/xen: add xen hypercall preemption David Vrabel
2015-02-05 18:15 ` Luis R. Rodriguez
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